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1
De Filippis, Giovanna, Christos Pouliaris, Daniel Kahuda, Teodora Vasile, Valentina Manea, Florian Zaun, Björn Panteleit, et al. "Spatial Data Management and Numerical Modelling: Demonstrating the Application of the QGIS-Integrated FREEWAT Platform at 13 Case Studies for Tackling Groundwater Resource Management." Water 12, no. 1 (December 20, 2019): 41. http://dx.doi.org/10.3390/w12010041.
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Because of the spatial nature of groundwater-related data and their time component, effective groundwater management requires the application of methods pertaining to the Information and Communication Technologies sector, such as spatial data management and distributed numerical modelling. The objective of this paper is to demonstrate the effectiveness of the QGIS-integrated FREEWAT platform and an approach combining spatial data management and numerical models to target groundwater management issues. FREEWAT is a free and open source platform integrated in a Geographic Information System environment and embedding tools for pre- and post-processing of spatial data and integrating numerical codes for the simulation of the hydrological cycle, with a main focus on groundwater. To this aim, this paper briefly presents the FREEWAT platform, introduces the FREEWAT approach, and showcases 13 case studies in European and non-European countries where the FREEWAT platform was applied. Application of the FREEWAT platform to real-world case studies is presented for targeting management of coastal aquifers, ground- and surface-water interaction, climate change impacts, management of transboundary aquifers, rural water management and protection of groundwater-dependent ecosystems. In this sense, compared to other existing software suites, FREEWAT allows data analysis and visualization to accomplish each step of the modelling workflow, i.e., from data analytics, to conceptual model definition, to numerical modelling and reporting of results. The presented experiences demonstrate that improved access to data and the portability of models and models’ results can help to promote water sustainability from the local- to the basin-scale. Furthermore, FREEWAT may represent a valuable tool to target the objective of increasing the capabilities of public authorities and private companies to manage groundwater resources by means of up-to-date, robust, well-documented and reliable software, without entailing the need of costly licensing, nowadays seldom affordable by public water authorities. Based on the strengths highlighted, the FREEWAT platform is a powerful tool for groundwater resources management, and for data collection, sharing, implementation and comparison of scenarios, for supporting planning and decision-making.
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Koltsida, Evgenia, and Andreas Kallioras. "Groundwater flow simulation through the application of the FREEWAT modeling platform." Journal of Hydroinformatics 21, no. 5 (July 10, 2019): 812–33. http://dx.doi.org/10.2166/hydro.2019.040.
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Abstract FREEWAT is a free and open source QGIS-integrated platform, developed to simulate several hydrological processes by combining the capabilities of geographic information system (GIS) for geo-processing and post-processing tools with several codes of the well-known USGS MODFLOW ‘family’. FREEWAT platform was applied for the groundwater flow simulation of a coastal aquifer system, located in northern Greece. The simulation was conducted using the MODFLOW_2005 code, the Observation Analysis Tool (a FREEWAT module facilitating the integration of time series observations into modeling), while the UCODE_2014 code was used as the main module for the sensitivity analysis and parameter estimation. The statistics used include composite scaled sensitivities, parameter correlation coefficients, and leverage. The simulation of the investigated aquifer system was found to be satisfactory, indicating that the simulated level values were slightly greater than the observed values after the optimization.
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Grodzynskyi, M. D. "INTERNATIONAL PROJECT FREEWAT ON PLANNING AND MANAGEMENT OF WATER RESOURCES: OBJECTIVES AND IMPLEMENTATION PROCESS." Ukrainian Geographical Journal 2016, no. 4 (November 1, 2016): 17–21. http://dx.doi.org/10.15407/ugz2016.04.017.
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De Filippis, Giovanna, Laura Ercoli, and Rudy Rossetto. "A Spatially Distributed, Physically-Based Modeling Approach for Estimating Agricultural Nitrate Leaching to Groundwater." Hydrology 8, no. 1 (January 11, 2021): 8. http://dx.doi.org/10.3390/hydrology8010008.
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Nitrogen-nitrate, while being fundamental for crop production, is of particular concern in the agricultural sector, as it can easily leach to the water table, worsening groundwater quality. Numerical models and Geographic Information System may support the estimation of nitrate leaching rates in space and time, to support sustainable agricultural management practices. In this paper, we present a module for the simulation of the processes involved in the nitrogen cycle in the unsaturated zone, including nitrate leaching. This module was developed taking steps from the ANIMO and EPIC model frameworks and coupled to the hydrological models integrated within the FREEWAT platform. As such, the nitrogen cycle module was then included in the FREEWAT platform. The developed module and the coupling approach were tested using a simple synthetic application, where we simulated nitrate leaching through the unsaturated zone for a sunflower crop irrigated district during a dry year. The results of the simulation allow the estimation of daily nitrate concentration values at the water table. These spatially distributed values may then be further used as input concentration in models for simulating solute transport in aquifers.
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Foglia, Laura, Iacopo Borsi, Steffen Mehl, Giovanna De Filippis, Massimiliano Cannata, Enric Vasquez-Suñe, Rotman Criollo, and Rudy Rossetto. "FREEWAT, a Free and Open Source, GIS-Integrated, Hydrological Modeling Platform." Groundwater 56, no. 4 (March 31, 2018): 521–23. http://dx.doi.org/10.1111/gwat.12654.
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Rossetto, Rudy, Iacopo Borsi, and Laura Foglia. "FREEWAT: FREE and open source software tools for WATer resource management." Rendiconti online della Società Geologica Italiana 35 (April 2015): 252–55. http://dx.doi.org/10.3301/rol.2015.113.
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De Filippis, Giovanna, Iacopo Borsi, Laura Foglia, Massimiliano Cannata, Violeta Velasco Mansilla, Enric Vasquez-Suñe, Matteo Matteo Ghetta, and Rudy Rossetto. "Software tools for sustainable water resources management: the GIS-integrated FREEWAT platform." Rendiconti Online della Società Geologica Italiana 42 (March 2017): 59–61. http://dx.doi.org/10.3301/rol.2017.14.
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Cannata, Massimiliano, Jakob Neumann, and Rudy Rossetto. "Open source GIS platform for water resource modelling: FREEWAT approach in the Lugano Lake." Spatial Information Research 26, no. 3 (October 16, 2017): 241–51. http://dx.doi.org/10.1007/s41324-017-0140-4.
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Geistefeldt, Justin, and Siavash Shojaat. "Comparison of Stochastic Estimates of Capacity and Critical Density for U.S. and German Freeways." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 8 (April 25, 2019): 388–96. http://dx.doi.org/10.1177/0361198119843471.
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The randomness of freeway capacity has been analyzed in a large number of studies. In contrast, relatively little attention has been paid to the critical density at capacity and its relationship to breakdown occurrence, although density is used as a quality of service criterion for freeways. In the paper, distributions of freeway capacity and critical density are estimated and compared based on traffic data samples from 38 freeway bottleneck sections in the U.S. and Germany. It is shown that the well-established methods for stochastic capacity analysis can be applied to estimate critical density distributions by replacing volume with density in the corresponding mathematical models. Comparison of the estimated capacity and critical density distribution functions reveals that the relative variability of the capacity is lower than the variability of the critical density. This suggests that traffic volume is the more appropriate parameter to represent the trigger of traffic breakdowns than traffic density. The empirical results also show that the rather smooth traffic flow on U.S. freeways leads to a smaller variance of both the capacity and the critical density distribution compared with German freeways, whereas the average capacity per lane is roughly the same.
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Yan, Yadan, Tianzhao Guo, and Dongwei Wang. "Dynamic Accessibility Analysis of Urban Road-to-Freeway Interchanges Based on Navigation Map Paths." Sustainability 13, no. 1 (January 3, 2021): 372. http://dx.doi.org/10.3390/su13010372.
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Accessibility is important for road network planning and design, especially the accessibility of freeway entrances and exits, which reflects the convenience of travelers using freeways and the rationality of the connection between urban roads and freeways. Based on the path information of navigation map software, a new comprehensive travel impedance model to dynamically analyze the accessibility of freeway entrances and exits was proposed. The dynamic accessibility of freeway entrances and exits in Zhengzhou was studied using the proposed comprehensive impedance model, and the calculation results were analyzed. The accessibility of freeway entrances and exits is characterized by dynamic changes; the accessibility during the off-peak evening period is the highest, while that during the morning peak period and evening peak period is lower. The results of the comprehensive impedance model are roughly consistent with reality. From a location perspective, regardless of the period of time, the accessibility of freeway entrances and exits in the central and surrounding areas of Zhengzhou is always at a lower level, and during the off-peak afternoon period, the accessibility of the eastern part of the city is notably higher than that of the western part. Additionally, the accessibility of freeway entrances and exits is closely related to the traffic status of the road network and the characteristics of regional land use. The information can provide feedback for planning road networks and provide a reference for road network planning and traffic facility design.
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Berg, Nate. "Take the Parkway to the Freeway to the Automated Roadway." Boom 6, no. 1 (2016): 45–50. http://dx.doi.org/10.1525/boom.2016.6.1.45.
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This article examines the history and future of freeway design, tracking its evolution from early parkways to the Interstate Highway System to the potential freeways to come. A mix of infrastructure, architecture and landscape, freeways have had an indelible impact on urban development throughout California and beyond. By understanding the development and design of freeways over the decades, we can better determine what we want this infrastructure to become in the near future.
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Avelar, Raul E., and Kay Fitzpatrick. "Safety Evaluation of Cross-Sectional Elements of Freeway Managed Lanes." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 14 (April 10, 2018): 20–28. http://dx.doi.org/10.1177/0361198118755703.
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This paper investigated the safety implications of managed-lane cross-sectional elements. The objective of the Federal Highway Administration project was to investigate the relationship between crashes and buffer-separated managed lane dimensions. The results from several previous research studies have demonstrated that reductions in freeway lane width or shoulder width are associated with more crashes. This research found that a narrower managed-lane envelope width (i.e., left shoulder, managed-lane, and buffer width combined) is also associated with more freeway crashes for crashes of all severity levels including fatal and injury. Wider envelopes are associated a reduction in total freeway crashes, of all severities, of 2.8% in Texas, and 2.0% in California, for each additional foot of envelope width. In California, wider envelopes are associated with a reduction of 4.4% in managed-lane-related crashes resulting in fatalities and injuries at all severity levels, for each additional foot of envelope width. The analysis was conducted on nonweaving managed-lane segments that included a single managed-lane separated from the general-purpose lanes with a flush buffer area. The dataset included crashes on 128.0 miles of freeway in California (all 128.0 miles with flush buffers) and 60.4 miles of freeway in Texas (41.7 miles with pylon buffers and 18.7 miles with flush buffers). The California sites included freeways with three or four general-purpose lanes, and the Texas freeways had three to five general-purpose lanes.
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Kwon, Jaimyoung, Pravin Varaiya, and Alexander Skabardonis. "Estimation of Truck Traffic Volume from Single Loop Detectors with Lane-to-Lane Speed Correlation." Transportation Research Record: Journal of the Transportation Research Board 1856, no. 1 (January 2003): 106–17. http://dx.doi.org/10.3141/1856-11.
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An algorithm for real-time estimation of truck traffic in multilane freeways was proposed. The algorithm used data from single loop detectors—the most widely installed surveillance technology for urban freeways in the United States. The algorithm worked for those freeway locations that have a truck-free lane and exhibit high lane-to-lane speed correlation. These conditions are met by most urban freeway locations. The algorithm produced real-time estimates of the truck traffic volumes at the location. It also can be used to produce alternative estimates of the mean effective vehicle length, which can improve speed estimates from single loop detector data. The algorithm was tested with real freeway data and produced estimates of truck traffic volumes with only 5.7% error. It also captured the daily patterns of truck traffic and mean effective vehicle length. Applied to loop data on Interstate 710 near Long Beach, California, during the dockworkers’ lockout October 1 to 9, 2002, the algorithm found a 32% reduction in five-axle truck volume.
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Khalifah Ibrahim, Fadel, Yadi Suryadi, Indratmo Soekarno, Sri Legowo, Mohammad Bagus Adityawan, and Saepul. "Water management system of peatlands for palawija plants on KHG Pulang Pisau, Central of Kalimantan." MATEC Web of Conferences 270 (2019): 04006. http://dx.doi.org/10.1051/matecconf/201927004006.
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Kesatuan Hidrologis Gambut (KHG) or Peat Hydrological Unit is a land which consist of incomplete soil decomposition of aquatic vegetation that is inundated with anaerobic conditions. Peatlands in Indonesia have common problem, which is adequacy of water availability (water balance) throughout the year and fire risk. This condition makes the holding of studies to ensure this. In this research, study uses secondary data of Peatlands, Pulang Pisau regency, Central of Kalimantan. This research will be modeling groundwater level using unconfined steady aquifer with finite difference method by Qgis Freewat. Then, if possible, the model will be calibrated by direct sampling at some point in the field, so the next will be modeling by comparison results of water level model with water level existing that up to 40 cm in accordance with Government Regulation no. 57 of 2016 on amendment to Government Regulation No. 71 of 2014 on the Protection and Management of Peat Ecosystems. From this research is expected to give some of benefits as follow: 1). Estimating water balance for Palawija Plants in KHG Pulang Pisau, 2). Modeling groundwater level for canal as one of the optimal water management efforts so that peatlands are not too dry and not too wet, so the risk of forest fires can be minimized.
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Carey, Jason, and John Semmens. "Impact of Highways on Property Values: Case Study of Superstition Freeway Corridor." Transportation Research Record: Journal of the Transportation Research Board 1839, no. 1 (January 2003): 128–35. http://dx.doi.org/10.3141/1839-14.
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The effects of freeway development on land use and property values were examined. A case study was prepared for the Superstition Freeway (US-60) corridor in Mesa and Gilbert, Arizona. Among the findings were the following observations. First, access benefits are transferred from highway users to nonusers through changes in property values. Freeway construction may have an adverse impact on some properties, but in the aggregate, property values tend to increase with freeway development. Second, freeways do not affect all properties' values in the same way. Proximity to the freeway was observed to have a negative effect on the value of detached single-family homes in the US-60 corridor but a positive effect on multifamily residential developments (e.g., condominiums) and most commercial properties. Finally, the most important factor in determining negative impact on property values appears to be the level of traffic on any major roads in the proximate area, which implies that regional traffic growth is more significant than the presence of a freeway per se.
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Corby, M. J., and F. F. Saccomanno. "Analysis of Freeway Accident Detection." Transportation Research Record: Journal of the Transportation Research Board 1603, no. 1 (January 1997): 80–89. http://dx.doi.org/10.3141/1603-11.
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Instrumented traffic management can assist in the detection of freeway incidents and reduce the time required to initiate effective traffic management strategies and emergency response measures. Although instrumented freeway traffic management is concerned primarily with general incidents, reportable vehicle accidents are the focus of this research. Reportable accidents account for 20 percent of all freeway incidents and give rise to much of the nonrecurrent traffic congestion experienced on many freeways. Explored here is how the use of various accident-detection criteria, such as change in speed, vehicle occupancy, and traffic volume, affects the time to detection for a mix of factors (preaccident traffic characteristics, accident lane-blockage pattern, position and distance of detector with respect to each accident). A representative sample of Toronto freeway accidents for 1994 was analyzed using analysis of variance. The results of this analysis suggest ways in which instrumented detection of freeway accidents can be made more efficient by reducing the time to detection.
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Liu, Chieh-Min, and Jyh-Ching Juang. "Estimation of Lane-Level Traffic Flow Using a Deep Learning Technique." Applied Sciences 11, no. 12 (June 17, 2021): 5619. http://dx.doi.org/10.3390/app11125619.
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This paper proposes a neural network that fuses the data received from a camera system on a gantry to detect moving objects and calculate the relative position and velocity of the vehicles traveling on a freeway. This information is used to estimate the traffic flow. To estimate the traffic flows at both microscopic and macroscopic levels, this paper used YOLO v4 and DeepSORT for vehicle detection and tracking. The number of vehicles passing on the freeway was then calculated by drawing virtual lines and hot zones. The velocity of each vehicle was also recorded. The information can be passed to the traffic control center in order to monitor and control the traffic flows on freeways and analyze freeway conditions.
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Weng, Jiancheng, Rongliang Yuan, Ru Wang, and Chang Wang. "Freeway Travel Speed Calculation Model Based on ETC Transaction Data." Computational Intelligence and Neuroscience 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/174123.
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Real-time traffic flow operation condition of freeway gradually becomes the critical information for the freeway users and managers. In fact, electronic toll collection (ETC) transaction data effectively records operational information of vehicles on freeway, which provides a new method to estimate the travel speed of freeway. First, the paper analyzed the structure of ETC transaction data and presented the data preprocess procedure. Then, a dual-level travel speed calculation model was established under different levels of sample sizes. In order to ensure a sufficient sample size, ETC data of different enter-leave toll plazas pairs which contain more than one road segment were used to calculate the travel speed of every road segment. The reduction coefficientαand reliable weightθfor sample vehicle speed were introduced in the model. Finally, the model was verified by the special designed field experiments which were conducted on several freeways in Beijing at different time periods. The experiments results demonstrated that the average relative error was about 6.5% which means that the freeway travel speed could be estimated by the proposed model accurately. The proposed model is helpful to promote the level of the freeway operation monitoring and the freeway management, as well as to provide useful information for the freeway travelers.
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Choi, W., A. M. Winer, and S. E. Paulson. "Factors controlling pollutant plume length downwind of major roadways in nocturnal surface inversions." Atmospheric Chemistry and Physics Discussions 13, no. 9 (September 30, 2013): 25253–90. http://dx.doi.org/10.5194/acpd-13-25253-2013.
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Abstract. A curve fit method using a Gaussian dispersion model solution was successfully applied to obtain both dispersion coefficients and a particle number emission factor (PNEF) directly from ultrafine particle (UFP) concentration profiles observed downwind of major roadways in California's South Coast Air Basin (SoCAB). The Briggs' formulation for the vertical dispersion parameter σz was adopted in this study due to its better performance in describing the observed profiles compared to other formulations examined. The two dispersion coefficients in Briggs' formulation, α and β, ranged from 0.02 to 0.07 and from −0.5 × 10−3 to 2.8 × 10−3, respectively, for the four freeway transects studied and are significantly different for freeways passing over vs. under the street on which measurements of the freeway plume were made. These ranges are wider than literature values for α and β under stable conditions. The dispersion coefficients derived from observations showed strong correlations with both surface meteorology (wind speed/direction, temperature, and air stability) and differences in concentrations between the background and plume peak. The relationships were applied to predict freeway plume transport using a multivariate regression, and produced excellent agreement with observed UFP concentration profiles. The mean PNEF for a mixed vehicle fleet on the four freeways was estimated as 1.2 × 1014 particles mi−1 vehicle−1, which is about 15% of the value estimated in 2001 for the I-405 freeway, implying significant reductions in UFP emissions over the past decade in the SoCAB.
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Suryadi, Yadi, Indratmo Soekarno, and Ivan Aliyatul Humam. "Effectiveness Analysis of Canal Blocking in Sub-peatland Hydrological Unit 5 and 6 Kahayan Sebangau, Central Kalimantan, Indonesia." Journal of Engineering and Technological Sciences 53, no. 2 (April 19, 2021): 210205. http://dx.doi.org/10.5614/j.eng.technol.sci.2021.53.2.5.
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The height of canal blocking has a significant influence on re-wetting peatland, depending on the canal’s distance. An effective canal in good condition has to raise the groundwater table to -0.4 m below ground level according to the Indonesian Ministry of Environment and Forestry (MENLHK). The effectiveness of different canal blockings was modeled by Freewat software with variation of canal distance (200 m, 250 m, 300 m, 350 m, and 400 m) and blocking height (0.2 m, 0.3 m, 0.4 m, 0.5 m, 0.6 m). This simulation was carried out using recharge and evapotranspiration data covering 20 years. The input of the conductivity value was done using 50 m/day according to the calibration. From the modeling, 0.6 m high canal blockings give a satisfactory result at every canal distance. The study took place during the annual dry season, when recharge was almost zero and average evapotranspiration was 6 mm/day. Adjusting the canal blocking to a maximum of 0.6 m and the canal distance to 400 m, the groundwater table slowly rose 0.38 m and it took 30 days to reach full-re-wetting capacity. This study revealed that the effectiveness of canal blocking is directly related to evapotranspiration and recharge, which has a positive correlation with the groundwater rise and the re-wetting period.
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DeCorla-Souza, Patrick. "Implementing Congestion Tolls on Currently Free Highways With Public–Private Partnerships: What Are the Financial and Economic Benefits?" Public Works Management & Policy 25, no. 4 (September 13, 2019): 341–64. http://dx.doi.org/10.1177/1087724x19869939.
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A trillion dollars in Interstate highway improvement and modernization work has been deferred due to lack of funding. More than half of Interstate and other freeway and expressway lane miles are classified as urban. Therefore, one approach that could be considered to generate needed revenue for freeway improvements in urban areas is implementing congestion-based tolls on freeways during peak periods when they are congested. Such an approach has been implemented in the Washington, DC metro area, on the I-66 freeway inside the Capital Beltway in Northern Virginia. This article demonstrates how an analyst may estimate the financial and economic benefits of a concept involving imposition of congestion-based tolls on the entire urban freeway network, during peak periods only, in conjunction with transit service improvements using automated transit vehicles. Furthermore, the article evaluates potential benefits from using a public–private partnership for implementation of the concept.
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Guo, Yong Qing. "The Relationship between Freeway Safety and Geometric Design Elements." Advanced Materials Research 424-425 (January 2012): 215–19. http://dx.doi.org/10.4028/www.scientific.net/amr.424-425.215.
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This paper mainly quantifies the safety effects of ramp spacing, and other geometric design elements of highway facilities. Negative Binomial (NB) regression models have been applied to estimate of different accident types, including total crashes, fatal-plus-injury crashes, single-vehicle crashes and multiple-vehicle crashes. Data for model estimation was collected in 112 freeway segments where each entrance ramp is followed by an exit ramp on I-5 in the Washington State, US. Three years (2005-2007) of freeway crashes has been examined by the NB model. The modeling results have been geared into the development of accident modification factors (AMFs) for ramp spacing that can be used safety prediction of freeways. Furthermore, the results also suggest some geometric designs are recommended to improve freeway safety
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Frey, H. Christopher, Maryam Delavarrafiee, and Sanjam Singh. "Real-World Freeway and Ramp Activity and Emissions for Light-Duty Gasoline Vehicles." Transportation Research Record: Journal of the Transportation Research Board 2627, no. 1 (January 2017): 17–25. http://dx.doi.org/10.3141/2627-03.
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There are few data on differences in real-world emissions by in-use vehicles when they operate on freeway ramps compared with operations on the freeway itself. The objective of this paper is to quantify the variability in link-based emissions rates for on-ramps and off-ramps in comparison to rates on freeways. Real-world measurements were made with the use of a portable emissions measurement system (PEMS) for selected vehicles, ramps, and freeway segments. The methodology included development of a study design for field data collection of vehicle activity and emissions, execution of the study design, quality assurance of the raw data, and analysis of the quality-assured data. Four light-duty gasoline vehicles were driven on two routes, each composed of on-ramp, freeway, and off-ramp links. Data were collected for morning peak, evening peak, and off-peak time periods. A PEMS test was used to measure exhaust emissions of oxides of nitrogen (NOx), hydrocarbon (HC), and carbon monoxide (CO). The emissions rates for on-ramps were shown to be substantially higher than rates on freeways for NOx, HC, and CO. Some of this variability in emissions rates can be explained by link average vehicle specific power, which can vary by time of day and from one location to another. The variability in emissions rates by route and time of day indicates that there can be complex interactions between traffic flow, road geometry, and emissions rates. Recommendations are offered for additional study and regarding how these results can be used by researchers and practitioners.
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Choi, W., A. M. Winer, and S. E. Paulson. "Factors controlling pollutant plume length downwind of major roadways in nocturnal surface inversions." Atmospheric Chemistry and Physics 14, no. 13 (July 4, 2014): 6925–40. http://dx.doi.org/10.5194/acp-14-6925-2014.
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Abstract. A fitting method using a semi-empirical Gaussian dispersion model solution was successfully applied to obtain both dispersion coefficients and a particle number emission factor (PNEF) directly from ultrafine particle (UFP; particles smaller than <0.1 μm in diameter) concentration profiles observed downwind of major roadways in California's South Coast Air Basin (SoCAB). The effective Briggs' formulation for the vertical dispersion parameter σz was adopted in this study due to its better performance in describing the observed profiles compared to other formulations examined. The two dispersion coefficients in Briggs' formulation, α and β, ranged from 0.02 to 0.07 and from −0.5 × 10−3 to 2.8 × 10−3, respectively, for the four freeway transects studied and are significantly different for freeways passing over vs. under the street on which measurements of the freeway plume were made. These ranges are wider than literature values for α and β under stable conditions. The dispersion coefficients derived from observations showed strong correlations with both surface meteorology (wind speed/direction, temperature, and air stability) and differences in concentrations between the background and plume peak. The relationships were applied to predict freeway plume transport using a multivariate regression, and produced excellent agreement with observed UFP concentration profiles. The mean PNEF for a mixed vehicle fleet on the four freeways was estimated as 7.5 × 1013 particles km−1 vehicle−1, which is about 15% of the value estimated in 2001 for the I-405 freeway, implying significant reductions in UFP emissions over the past decade in the SoCAB.
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Wesemann, Larry, Tijana Hamilton, and Steve Tabaie. "Traveler Response to Damaged Freeways and Transportation System Changes following Northridge Earthquake." Transportation Research Record: Journal of the Transportation Research Board 1556, no. 1 (January 1996): 96–108. http://dx.doi.org/10.1177/0361198196155600112.
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When four key freeways in Southern California were damaged on January 17, 1994, by the Northridge earthquake, state and local agencies implemented a variety of emergency measures to the transportation systems in damaged corridors to ensure some degree of mobility during reconstruction. Travelers who had used damaged routes were faced with a variety of travel choices, such as using primary roadway detours, ridesharing, diverting to other roads, using transit, avoiding travel, telecommuting, or changing time of travel. On the basis of comprehensive travel surveys, traffic monitoring, and data collection, it was determined that travelers responded in significantly different ways in each of the four damaged corridors. In the very heavily traveled I-10 (Santa Monica) Freeway Corridor, even though primary roadway detours could only carry approximately 40 percent of normal freeway capacity, virtually all travelers still drove their automobiles because numerous parallel streets exist in this corridor as alternatives to the freeway. By contrast, research showed that some 7,000 users of the I-5 (Golden State) and SR-14 (Antelope Valley) freeways shifted to commuter trains because parallel roadways were limited. In addition, although most travelers quickly returned to their original trip making choices and mode of travel after damaged freeways were opened, other travelers (including many train riders) chose to remain with the new travel choices for a variety of behavioral reasons, including reliability. Further research indicated that when travelers in Southern California were forced to choose from a variety of new travel choices, their decision making followed a logical hierarchy based on specific trip making requirements and travel time thresholds, as well as their perceptions of the suitability of each choice for their own particular travel needs.
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Hudda, N., S. Fruin, R. J. Delfino, and C. Sioutas. "Efficient determination of vehicle emission factors by fuel use category using on-road measurements: downward trends on Los Angeles freight corridor I-710." Atmospheric Chemistry and Physics 13, no. 1 (January 11, 2013): 347–57. http://dx.doi.org/10.5194/acp-13-347-2013.
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Abstract. To evaluate the success of vehicle emissions regulations, trends in both fleet-wide average emissions as well as high-emitter emissions are needed, but it is challenging to capture the full spread of vehicle emission factors (EFs) with chassis dynamometer or tunnel studies, and remote sensing studies cannot evaluate particulate compounds. We developed an alternative method that links real-time on-road pollutant measurements from a mobile platform with real-time traffic data, and allows efficient calculation of both the average and the spread of EFs for light-duty gasoline-powered vehicles (LDG) and heavy-duty diesel-powered vehicles (HDD). This is the first study in California to report EFs under a full range of real-world driving conditions on multiple freeways. Fleet average LDG EFs were in agreement with most recent studies and an order of magnitude lower than observed HDD EFs. HDD EFs reflected the relatively rapid decreases in diesel emissions that have recently occurred in Los Angeles/California, and on I-710, a primary route used for goods movement and a focus of additional truck fleet turnover incentives, HDD EFs were often lower than on other freeways. When freeway emission rates (ER) were quantified as the product of EF and vehicle miles traveled (VMT) per time per mile of freeway, despite a two- to three-fold difference in HDD fractions between freeways, ERs were found to be generally similar in magnitude. Higher LDG VMT on low HDD fraction freeways largely offset the difference. Therefore, the conventional assumption that freeways with the highest HDD fractions are significantly worse sources of total emissions in Los Angeles may no longer be~true.
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Ullman, Gerald L., and Conrad L. Dudek. "Theoretical Approach to Predicting Traffic Queues at Short-Term Work Zones on High-Volume Roadways in Urban Areas." Transportation Research Record: Journal of the Transportation Research Board 1824, no. 1 (January 2003): 29–36. http://dx.doi.org/10.3141/1824-04.
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A new theoretical approach is described that more accurately predicts the length of queues that will develop when one or more lanes are closed for short-term freeway road work in an urban area. A model was developed that represents the interactions between diversion and traffic queuing on the freeway. The model is based on macroscopic fluid-flow analogies of traffic and a new perspective of the freeway corridor as a section of permeable pipe. Historical traffic volumes on the roadway serve as the primary data input into the model. Unlike other work zone analysis methods, the model presents a rational representation of how traffic queues stabilize upstream of temporary work zone bottlenecks in urban areas. The model can be calibrated to reasonably represent the magnitude of traffic queues developing upstream of actual work zone lane closures on urban freeways in Texas.
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Kim, Jin-Tae, Kenneth G. Courage, Scott S. Washburn, and Gina Bonyani. "Framework for Investigation of Level-of-Service Criteria and Thresholds on Rural Freeways." Transportation Research Record: Journal of the Transportation Research Board 1852, no. 1 (January 2003): 239–45. http://dx.doi.org/10.3141/1852-29.
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The Highway Capacity Manual prescribes level-of-service (LOS) criteria as a function of traffic density to categorize the operational conditions of both rural and urban freeway sections. This density-based level of service is ideally suited to the assessment of urban freeways when the performance must be optimized to meet high traffic demand. There is, however, some question as to whether density is the appropriate indicator of the quality of service on rural freeways, since drivers may think more in terms of psychological or emotional comfort for freeways, which generally serve long, high-speed trips and rarely experience more than moderate congestion levels. Three specific measures are examined that have at least an intuitive relationship to the concept of driver comfort: ( a) acceleration noise, which is a measure of the physical turbulence in the traffic stream; ( b) number and duration of cruise control applications, which could serve as a general indication of driver convenience or inconvenience; and ( c) percent time spent following, which is already accepted as the basis for determining the level of service on rural two-lane highways. The three candidate measures were estimated for a hypothetical section of rural freeway by simulation, using the CORSIM model. The kinematic relationships of individual vehicles within the traffic stream were estimated by postprocessing the simulation data for each second of operation. All of the measures considered in this study have conceptual appeal. All have produced interesting and potentially usable results with respect to their relationships to traffic volume. Although the simulation results are interesting, further studies focusing on driver opinions, behavior, or field measurements, or all three, would likely be necessary to support the development and recommendation of a specific set of LOS criteria that recognizes the differences between the urban and rural freeway driving environments.
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Jiang, Shui Long, and Hong Qi Liu. "Applicability Analysis and Installation Techniques of Driver Feedback Sign on Freeway in China." Applied Mechanics and Materials 209-211 (October 2012): 987–91. http://dx.doi.org/10.4028/www.scientific.net/amm.209-211.987.
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The Driver Feedback Sign (DFS) has been widely used abroad to reduce the vehicle speed to improve traffic safety level, but it only be used on a few of freeways and urban expressways in China, and there have no research on its application effect. In order to popularization and application the DFS in China, the paper analyzed the DFS application situation at home and broad by document retrieval, comparatively analyzed implement effect before and after installing DFS on Badaling freeway by vehicle speed survey and questionnaires survey. At last, the paper comprehensively analyzed the applicability of DFS on freeway in China and proposed the installing requirement and technical requirement.
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Kim, Ju-Young, Jin-Tae Kim, and Wonchul Kim. "Psycho-physiological responses of drivers to road section types and elapsed driving time on a freeway." Canadian Journal of Civil Engineering 42, no. 11 (November 2015): 881–88. http://dx.doi.org/10.1139/cjce-2014-0392.
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This paper addresses drivers’ psycho-physiological condition under the influence of various freeway section types and elapsed driving times. The authors analyzed the electroencephalogram (EEG) signals (α, β, and θ) of 51 drivers on a freeway in Korea. The findings show that the driver’s workload increases in tunnels and on left-curved sections, and that his or her concentration and response ability decrease after 60 min of elapsed driving time. The β/α ratios of EEG signals were found to be most effective in detecting differences in psycho-physiological responses. The results can help to promote safety on freeways by encouraging drivers to take rests every hour.
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Bittner, Daniel, Ayla Rychlik, Tobias Klöffel, Anna Leuteritz, Markus Disse, and Gabriele Chiogna. "A GIS-based model for simulating the hydrological effects of land use changes on karst systems – The integration of the LuKARS model into FREEWAT." Environmental Modelling & Software 127 (May 2020): 104682. http://dx.doi.org/10.1016/j.envsoft.2020.104682.
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Eyler, Dennis R. "Arterial Interchange." Transportation Research Record: Journal of the Transportation Research Board 1912, no. 1 (January 2005): 65–71. http://dx.doi.org/10.1177/0361198105191200108.
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A family of interchange designs has been developed for arterial roadways that will not become freeways. These designs are compact and inexpensive. A critical feature that makes the designs unsuitable for freeways is that each roadway would have at-grade intersections. Called arterial interchanges, these designs are needed because traffic growth has caused the major intersections on many arterial roadways to reach capacity. Those intersections often have three through lanes and double left-turn lanes, and now triple left-turn lanes are in use. Large intersections are a problem for pedestrians and for signal control. These large intersections experience high crash rates and traffic delays. The limits for at-grade intersections have been reached. What is next if traffic grows? Conversion to a freeway is the traditional solution, but this is expensive, time-consuming, and often opposed. Adding through lanes is also expensive and an inefficient way to increase the capacity of a few intersections. Often, congestion at only one intersection controls the capacity of a corridor. If a freeway interchange design is used, new problems are created, including weaving, loss of access, and added right of way. The arterial interchange concept, if used along an entire corridor, will create a new type of arterial roadway that will provide 75% of the benefits of a freeway with only 50% of the impact. The arterial interchanges were analyzed with the use of traffic simulation (VISSIM), and those results, along with the estimated construction costs, are presented.
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Saha, Rajib, Mosammat Tahnin Tariq, and Mohammed Hadi. "Deep Learning Approach for Predictive Analytics to Support Diversion during Freeway Incidents." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 6 (June 2020): 480–92. http://dx.doi.org/10.1177/0361198120917673.
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Route diversion during incidents on freeways has been proven to be a useful tactic to mitigate non-recurrent congestion. However, the capacity constraints created by the signals on the alternative routes put limits on the diversion process since the typical time-of-day (TOD) signal control cannot handle the sudden increase in the traffic on the arterials because of diversion. Thus, there is a need for active transportation management strategies that support agencies in identifying the potential diversion routes for freeway incidents and the need for adjusting the traffic signal timing under different incident and traffic conditions. This paper investigates the use of a data analytic approach based on the long short-term memory (LSTM) deep neural network method to predict the alternative routes dynamically using incident attributes and traffic status on the freeway, and travel time on both the freeway and alternative routes during the incident. Additionally, a methodology is proposed for the development of special signal plans for the critical intersections on the alternative arterials based on the results from the LSTM neural network, combined with simulation modeling, and signal timing optimization. The methodology developed in the paper can be easily implemented by the transportation agencies, as it is based on data that are generally available to the agencies. The results from this paper indicate that the developed methodology can be used as part of a decision support system (DSS) to manage the traffic proactively during the incidents on the freeways.
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Chityala, Sneha, John O. Sobanjo, Eren Erman Ozguven, Thobias Sando, and Richard Twumasi-Boakye. "Driver Behavior at a Freeway Merge to Mixed Traffic of Conventional and Connected Autonomous Vehicles." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 11 (September 16, 2020): 867–74. http://dx.doi.org/10.1177/0361198120950721.
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Freeway merge ramps serve as one of the most challenging areas in traffic operations. This paper primarily focuses on creating a mixed traffic of conventional and connected/autonomous vehicles (CAVs) on freeways, and capturing driver behaviors both for the merging vehicle on the ramp and the freeway vehicles. The mixed distribution of vehicle headways of the freeway vehicles, developed based on various market penetration rates of the CAVs, was used to randomly generate vehicles through Monte Carlo simulation, and assigned as headways in a driving simulator. Based on perception, young drivers on the merge ramp were observed to choose critical headway gaps of 2.9 s, 1.8 s, and 1.7 s for freeway traffic of 0%, 50%, 75% penetration rates, respectively. For similar CAV penetration rates, the critical gaps observed for elderly drivers were 3.5 s, 2.0 s, and 1.9 s, respectively. When actually driving in the simulator, for the scenarios of 0% CAVs and 50% CAVs on the freeway, the values of average headway gaps accepted by young drivers were estimated as 2.36 s and 1.53 s, respectively. For the elderly drivers driving the simulator, the average headway gap values accepted were estimated as 2.72 s and 1.55 s, respectively, in the 0% and 50% penetration rates on the freeway traffic. Analyses of the speed profiles of the vehicles showed the effects of the acceleration/deceleration of merging vehicles, for both young and older drivers, on the freeway vehicles, including a few cases of collision. Overall, it was observed that the subject drivers accepted shorter headway gaps for increased CAV penetration levels.
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Guo, Yong Qing. "Effects of Ramp Spacing on Freeway Mainline Crashes." Applied Mechanics and Materials 97-98 (September 2011): 95–99. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.95.
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This research applies Negative Binomial regression models to investigate safety effects of ramp spacing. Data for model estimation was collected in 112 freeway segments where each entrance ramp is followed by an exit ramp. Three years (2005-2007) of freeway crash data were examined by the NB model in this study. The modeling results suggest that the frequencies of total crashes, fatal-plus-injury crashes, single-vehicle crashes and multiple-vehicle crashes increase as ramp spacing decreases, and the frequencies of total crashes and multiple-vehicle crashes increase at significant rates. The modeling result has been geared into the development of accident modification factors (AMFs) for ramp spacing that can be used safety prediction of freeways.
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Ullman, Gerald L., and Michael A. Ogden. "Analysis of Major Freeway Incidents in Houston, Texas." Transportation Research Record: Journal of the Transportation Research Board 1554, no. 1 (January 1996): 221–27. http://dx.doi.org/10.1177/0361198196155400126.
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An analysis of major freeway incidents in Houston, Texas, was conducted. The data base analyzed was provided by the Houston Police Department solo motorcycle patrol division. This division responds to all freeway lane-blocking incidents that are expected to last more than approximately 45 minutes. Over a 7-year period between 1986 and 1992, the division documented the details of 612 major freeway incidents to which it responded. From these data, it was estimated that major freeway incidents occur in Houston at a rate of 0.68 incident per 100 million vehicle-kilometers (MVK). That is equivalent to a major incident every 147 MVK. Major incidents were nearly 3.5 times as likely to occur within the interchanges (based on vehicle-kilometers driven) as between them. Of the 612 major incidents included in the data base, 498 (81.5 percent) involved trucks only (even though large truck traffic accounts for only 7.7 percent of the total vehicle-kilometers traveled on Houston freeways). Furthermore, lost or spilled loads and truck overturns account for nearly one-half of the major incidents in Houston. Information on incident severity and duration is also presented.
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Huynh, Peter, Muhammad T. Salam, Tricia Morphew, Kenny Y. C. Kwong, and Lyne Scott. "Residential Proximity to Freeways is Associated with Uncontrolled Asthma in Inner-City Hispanic Children and Adolescents." Journal of Allergy 2010 (June 13, 2010): 1–7. http://dx.doi.org/10.1155/2010/157249.
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Background. Proximity to heavy traffic has been linked to increased asthma severity. However, it is unknown whether exposure to heavy traffic is associated with the ability to maintain asthma control. Objectives. This study examines whether exposure to heavy traffic is associated with the ability to maintain asthma control in inner-city children. Methods. 756 inner-city asthmatic Hispanic children were followed for one year in a pediatric asthma management program (Breathmobile). At each scheduled visit, asthma specialist tracked patients' asthma severity and managed their asthma based on the NAEPP guidelines. The patients' residential distance from the nearest freeway was calculated based on residential address at study entry. Distance to nearest freeway was used as a surrogate marker for high exposure from traffic-related air pollutants. Results. Patients who lived near a freeway were significantly more likely to have asthma that was not well controlled (). Patients with intermittent and mild baseline severity have a two-fold increased risk of having asthma that is uncontrolled if they lived miles from a freeway (, ). Conclusion. In children with asthma, residential proximity to freeways is associated with uncontrolled asthma.
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Barth, Matthew J., Eric Johnston, and Ramakrishna R. Tadi. "Using GPS Technology to Relate Macroscopic and Microscopic Traffic Parameters." Transportation Research Record: Journal of the Transportation Research Board 1520, no. 1 (January 1996): 89–96. http://dx.doi.org/10.1177/0361198196152000111.
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Traffic congestion on today's freeways is a serious problem, causing significant delays for both passengers and goods. Freeway traffic congestion also results in increased vehicle emissions; however, this increase has not been quantified using current vehicle emission models. Current models use emission factors based on driving cycles that do not properly represent freeway driving characteristics. This paper presents a new methodology for relating the macroscopic speed, flow, and density parameters measured by traffic sensors with statistics of microscopic driving traces under different levels of congestion. This approach can be used to better estimate freeway emissions when combined with an appropriate modal emissions model. Preliminary experimentation has been carried out with a vehicle equipped with global positioning system (GPS) instrumentation, allowing for precise localization in both space and time. With the GPS, second-by-second velocity traces are acquired and matched with simultaneously measured freeway traffic data obtained by embedded traffic sensors. Statistical measures of velocity variation are derived from the velocity traces and are functionally related to the macroscopic traffic parameters of speed, flow, and density. Given a known distribution of vehicle types, models, and model years, vehicle emissions can be related to these statistical measures of velocity variation using a modal emission model, and, thus given speed-flow-density measures of freeway traffic, localized emissions estimates can be made.
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Al-Kaisy, A., J. A. Stewart, and M. Van Aerde. "A simulation approach for examining capacity and operational performance at freeway diverge areas." Canadian Journal of Civil Engineering 26, no. 6 (December 1, 1999): 760–70. http://dx.doi.org/10.1139/l99-038.
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Freeway diverge areas, and particularly those in the proximity of exit ramps, are often viewed as potential bottlenecks in freeway operations. The existing diverge procedures within the 1994 and 1997 Highway Capacity Manual updates are limited in that they do not provide a direct estimate of freeway capacity nor do they model performance at oversaturated traffic conditions. Moreover, a parallel investigation on these procedures revealed some inconsistencies in predicting measures of performance at those critical areas. This paper describes the use of computer traffic simulation to explore the patterns of capacity and operational performance behaviour at these areas under the impact of some key geometric and traffic variables. For this purpose, the microscopic traffic simulation model INTEGRATION was selected to conduct an extensive experimental work on a typical ramp-freeway diverge section. Five control variables were investigated, namely, total upstream demand, off-ramp demand, length of deceleration lane, off-ramp free-flow speed, and number of lanes at mainline. The impact of upstream or downstream ramps is considered beyond the scope of this research. Except for off-ramp free-flow speed, the impact of other control variables on capacity and operational performance was shown to be significant. Also, the simulated trends of traffic behaviour showed considerable agreement with logic and expectations in light of the current state of knowledge on freeway operations.Key words: freeways, diverge, capacity, operations, traffic simulation.
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Bassan, Shy, and Abishai Polus. "Meaning of actual capacity of freeways and its estimation." Canadian Journal of Civil Engineering 37, no. 1 (January 2010): 77–87. http://dx.doi.org/10.1139/l09-123.
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The flow on urban and suburban freeways is characterized typically by high densities, occupancies, and frequent breakdowns, particularly when the volume approaches capacity. This creates unstable flow conditions, resulting in recurrent as well as random congestion. The purpose of this study was twofold: (1) to develop models for evaluating flow characteristics on a busy suburban freeway, specifically speed versus flow and flow versus occupancy; (2) to understand the meaning of capacity by evaluating the actual capacity of a freeway section. The data were collected on Highway 1 in Israel and on Interstate 66 in Virginia, USA. Previous observations showed that both freeways operated at a saturated-flow condition almost daily and that breakdowns of the stream occurred often, though not daily. The paper presents a concept that suggests that freeway capacity is an actual-site specific term. This capacity can change frequently in space and time, depending on the section geometry, the time interval, the prevailing traffic and environmental conditions, and driving behavior. Determination of a representative value of actual capacity for level-of-service or planning analyses is suggested, based on one of three methods: parabolic curve-fitting for free-flow, dense congested stable (DCS) flow, and breakdown-flow data; the intersection of the best-fit stable-flow parabola and the equal-density adjusted line; and curve fitting of one-regime models to flow-occupancy data. Also included is a comparison with the 2000 Highway capacity manual (HCM) models and with capacity estimates from other studies. The results showed similar values of actual capacity estimates for the three methods.
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Tafti, Mehdi Fallah. "A Study on the Merits for Coordinated Use of Ramp Metering and Variable Speed Limit Traffic Control Systems." Open Transportation Journal 12, no. 1 (July 5, 2018): 230–45. http://dx.doi.org/10.2174/1874447801812010230.
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Aim:The aim of this research was to investigate the merits for further improvements of traffic operation on freeways and expressways through coordinated use of Ramp Metering and Variable Speed limit (VSL) control systems.Methods:In this research, the widely used ALINEA Ramp Metering strategy was coordinated with a rule-based VSL strategy so that the total flow entered from the upstream freeway and entry ramp is maintained below the merge downstream capacity. The developed algorithm was then examined on a freeway network comprising two merge and one diverge sections, using VISSIM microscopic simulation model. The performance of the simulated network was examined under three scenarios namely, No-control, Ramp Metering only and Ramp Metering plus VSL controls. The network performance under each scenario was then assessed and compared using three measures of performance namely, average travel time, overall delay and freeway throughput. The ANOVA test was used to analyze and compare the impacts of specified scenarios.Results:The results indicated that the best performance is achieved under coordinated Ramp Metering plus VSL scenario as it produced a significantly better performance in comparison with the other two scenarios.Conclusion:The results can be attributed to the synergistic effects of coordinated and integrated use of these control systems on the freeway network and therefore, coordination of such systems is recommended.
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Hudda, N., S. Fruin, R. J. Delfino, and C. Sioutas. "Cost effective determination of vehicle emission factors using on-road measurements." Atmospheric Chemistry and Physics Discussions 12, no. 7 (July 31, 2012): 18715–40. http://dx.doi.org/10.5194/acpd-12-18715-2012.
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Abstract. To evaluate the success of vehicle emissions regulations, trends in both fleet-wide average emissions as well as high-emitter emissions are needed, but it is challenging to capture the full spread of vehicle emission factors (EFs) with chassis dynamometer, tunnel or remote sensing studies. We developed an efficient and cost-effective method using real-time on-road pollutant measurements from a mobile platform, which when linked with real-time traffic data, allows calculating both the average and spread of EFs for light-duty gasoline-powered vehicles (LDV) and heavy-duty diesel-powered vehicles (HDV). This is the first study in California to report EFs under a wide range of real-driving conditions on multiple freeways and it captured much or most of the variability in EFs due to inter-vehicle differences. Fleet average LDV EFs were generally in agreement with most recent studies and an order of magnitude lower than HDV EFs, but over an order of magnitude or more spread was observed for both LDV and HDV EFs. HDV EFs reflected relatively rapid decreases occurring in diesel emissions in Los Angeles/California, and HDV EFs on I-710, a primary route used for goods movement and a focus of additional truck fleet turnover incentives, were lower than on other freeways. When freeway emission rates (ER) were quantified as the product of EF and vehicle activity rates per mile of freeway, ERs were found to be generally similar in magnitude. Despite a two- to three-fold difference in HDV fractions between freeways, higher LDV volumes largely offset this difference.
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Shojaat, Siavash, Justin Geistefeldt, and Brian Wolshon. "Optimum Volume of Freeway Corridors." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 3 (February 25, 2020): 27–36. http://dx.doi.org/10.1177/0361198120908249.
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Conventional methods to assess the quality of service on freeways are based on the comparison of a specific peak hour traffic demand to the capacity of the facility, which is usually measured at a single uniform bottleneck section. However, estimating the quality of service of one bottleneck section may not be sufficient to assess the performance of an entire freeway facility. A driver traveling along a freeway corridor may actually encounter multiple flow breakdowns at independent bottleneck sections, which affect the overall quality of service. This paper introduces a comprehensive approach that considers an entire freeway corridor as a system consisting of successive independent bottlenecks with different characteristics, and can be used to estimate the optimum sustainable volume. The methodology is based on the sustained flow index, which is defined as the product of traffic volume and the probability of survival at this volume. Optimum volumes of two real-world corridors are estimated based on the new derivations. The empirical results reveal that the optimum volume and the capacity of an entire corridor is less than those of its most restrictive bottleneck.
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Mousazadeh Gilandeh, Mojtaba, Sari Sharif Ali, Mohammad Javad Goodarzi, Nahid Amini, and Hassan Latifi. "Modelling of Queue Length in Freeway Work Zones – Case Study Karaj-Tehran Freeway." Promet - Traffic&Transportation 33, no. 1 (January 31, 2021): 49–59. http://dx.doi.org/10.7307/ptt.v33i1.3582.
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In this study, the traffic parameters were collected from three work zones in Iran in order to evaluate the queue length in the work zones. The work zones were observed at peak and non-peak hours. The results showed that abrupt changes in Freeway Free Speed (FFS) and arrival flow rate caused shockwaves and created a bottleneck in that section of the freeway. In addition, acceleration reduction, abrupt change in the shockwave speed, abrupt change in the arrival flow rate and increase in the percentage of heavy vehicles have led to extreme queue lengths and delay. It has been found that using daily traffic data for scheduling the maintenance and rehabilitation projects could diminish the queue length and delay. Also, by determining the bypass for heavy vehicles, the delay can be significantly reduced; by more than three times. Finally, three models have been presented for estimating the queue length in freeway work zones. Moreover, the procedure shown for creating a queue length model can be used for similar freeways.
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Hostovsky, Charles, and Fred L. Hall. "Freeway Quality of Service: Perceptions from Tractor-Trailer Drivers." Transportation Research Record: Journal of the Transportation Research Board 1852, no. 1 (January 2003): 19–25. http://dx.doi.org/10.3141/1852-03.
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Trucks make up a significant and growing portion of the traffic on freeways. The perceptions of tractor-trailer drivers regarding the quality of service on freeways are the subject of this research, with a focus on the factors that are important to this group of road users. Perceptions were determined using the standard qualitative inductive analysis approach through a focus group with professional tractor-trailer drivers. The results were compared with quality-of-service focus groups held for urban and rural freeway commuters. Freeway conditions in general were the most frequently mentioned factors and encompassed a variety of considerations. The three variables that together describe traffic conditions—travel time (or speed), traffic density (or maneuverability), and traffic flow—were all mentioned with regard to quality of service. Likely the most significant finding is that it is not traffic density that matters to these drivers; rather it is traffic flow. It appears that there is a comfortable operating range of highway speeds in which not much braking and acceleration-related gear changing are required. Other important themes included weather, attitudes toward other drivers, and road rage (i.e., aggressive driving). Participants also responded to questions about regional differences in quality of service. Safety was an issue that transcended or overlapped many other issues.
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Baird, Malcolm, Lori Cove, Frank Horne, and Bill Jacobs. "Development of Tennessee’s Freeway Service Patrol (HELP) Program." Transportation Research Record: Journal of the Transportation Research Board 1856, no. 1 (January 2003): 87–95. http://dx.doi.org/10.3141/1856-09.
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Many studies have been conducted to describe and evaluate the benefits of freeway service patrols, but much less is known about the planning and institutional development of such programs. This case study describes the implementation of Tennessee’s freeway service patrols. In 1998 the Tennessee Department of Transportation (TDOT) began planning for patrols to operate on the highest-volume freeways in the state’s four largest cities—Chattanooga, Knoxville, Memphis, and Nashville. After a staged implementation plan, TDOT has successfully implemented the patrols, known as HELP, in all four cities while also moving forward with related intelligent transportation system and incident management initiatives. Five aspects of program development are described that have been especially important to the success of the program—teamwork, attention to human resource issues, comprehensive training, first-rate vehicles and equipment, and communications.
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Thewalt, Christopher R., and Božidar Stojadinović. "Behavior of Bridge Outrigger Knee Joint Systems." Earthquake Spectra 11, no. 3 (August 1995): 477–509. http://dx.doi.org/10.1193/1.1585824.
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The catastrophic collapse of the Cypress Street Viaduct during the 1989 Loma Prieta earthquake emphasized the vulnerability of older elevated freeway bridge structures. One part of a joint Caltrans/University of California at Berkeley research project is the investigation of outrigger knee joints found in elevated freeway bents. This project has two principal goals: to evaluate the behavior of the existing outrigger knee joint systems under a combined transverse and longitudinal loading, and to design and experimentally verify upgrading strategies and repair techniques suitable for application on the existing elevated freeways. The primary focus of this paper will be to present the behavior of the as-built and upgraded systems, but an overview of the design method and the analytical tools used in the upgrade will also be presented.
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Wu, Qiong, and Jian Jun Wang. "Exploration on Speed-Limit Signs of Traffic Accident Section on Freeways." Applied Mechanics and Materials 361-363 (August 2013): 2349–52. http://dx.doi.org/10.4028/www.scientific.net/amm.361-363.2349.
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In order to improve freeways traffic safety, reduce staff and vehicles casualties and prevent secondary traffic accidents, the accident site section on freeway is divided into six regions of the warning zone, the upstream transition zone, the buffer zone, the accident zone, the downstream transition zone and the termination zone. Establish the warning zone speed-limit model by considering the relevant factors of driver's field of vision and transportation distance of visual cognition and then speed-limit programs are proposed according to the warning area speed-limit model. Speed-limit signs of the warning zone take phased settings based on both of those. The results show that the proposed warning area speed limit model conforms to the actual need, decision science, and having important practical value for freeway traffic safety.
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Mao, Xinhua, Jiahua Gan, and Xilong Zhao. "Debt Risk Evaluation of Toll Freeways in Mainland China Using the Grey Approach." Sustainability 11, no. 5 (March 7, 2019): 1430. http://dx.doi.org/10.3390/su11051430.
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With a proactive loan policy to raise construction funds, a large number of toll freeways have been built in Mainland China in the past three decades. However, it brought about a long-term heavy debt burden for most provincial governments. To ensure financial sustainability of toll freeways, an accurate and appropriate debt risk evaluation has become necessary. This research aims to explore debt risk factors and calculate the overall debt risk levels of toll freeways using the grey approach. Debt risk factors were identified as belonging to five categories—debt scale, debt structure, debt management, external environment, and solvency—and three new debt risk factors were added for specific concern of toll freeways—toll revenue, free cash flow, and earnings before interest, tax, depreciation, and amortization (EBITDA) margin. Debt risk levels of toll freeways in 29 provinces in Mainland China were evaluated by the proposed method and classified into three groups–low debt risk, medium debt risk, and high debt risk according to grey possibility degree ranges. Calculation results show that six provinces have low debt risk, 10 provinces have medium debt risk, and 13 provinces have high debt risk. Additionally, some specific policies to reduce toll freeway debt risk were provided based on the evaluation findings.
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Rostami, Mohsen, and Amir Esmael Forouhid. "REGRESSION ANALYSIS OF NOISE POLLUTION USING SPATIAL INFORMATION SYSTEM (CASE STUDY: TEHRAN CITY)." Akustika 32 (March 1, 2019): 346–50. http://dx.doi.org/10.36336/akustika201932346.
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Noise pollution is a type of environmental pollution threatening the health of community and living organisms. Research show that both short and long-term exposure to noise pollution weakens hearing, increases blood pressure leading to cardiovascular disorders, causes sleep and mood disorders and changes behavior patterns. Urbanism and vehicles have increased noise pollution. Nowadays, noise pollution studies is an important subject in environmental studies. This paper attempts to investigate noise pollution in Tehran considering the population growth and large contributing of vehicles to this type of pollution. The study areas consisted of high traffic areas of Tajrish, Tohid, Hemmat and Hakim Freeways. In a field study, the noise level was measured via sound meter and the noise map was generated based on geostatistical methods via GIS software. For this purpose, the factors influencing noise level (e.g. traffic, road width, slope, and residential or administrative-commercial land use) were surveyed and recorded for each point and their local and time dependencies were computed via SPSS. The results indicated that by a large margin, traffic was the most influential factor on noise level, followed by residential areas, road width, slope, administrative-commercial land use, and green space. According to the noise pollution map, Hemmat Freeway had the highest level of noise pollution, respectively followed by Hakim Freeway, Tohid, and Tajrish areas. It appears that the freeway function of Hemmat and Hakim areas and their relatively longer distance from residential areas has significantly influenced the noise pollution level. In most streets of the area, newly constructed, multi-story buildings prevent the roads from being widened, however it is proposed to prevent the construction of tall buildings around the main streets and maintain standard distances between buildings and main streets or freeways.