Journal articles: 'Ramps (Interchanges)'

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Sun, Jian Cheng, Hong Xu Lu, and Chen Feng Chen. "The Land Occupation Analysis of the Loop-Ramp Patterns of Freeway Trumpet Interchanges." Advanced Materials Research 1065-1069 (December 2014): 3388–92. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.3388.

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Interchange is not merely a major way of the intersection of main highways but also one of the important structures of freeway.And trumpet interchange is an important pattern of interchange. The design speed of ramps,the linearity indices of ramps and the patterns of loop ramps are the main influencing factors for the land occupation of freeway trumpet interchange.In this article, their influence on the land occupation have been analyzed in the first.Since then, specific studies between the land occupation and the loop-ramp patterns of trumpet interchanges.Finally, some advices were given to the design of interchanges.

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Jovanović, Goran, and Rafko Atelšek. "Study of a Highly Effective and Affordable Highway Interchange - ITL Interchange." Civil Engineering Journal 6, no. 4 (2020): 820–29. http://dx.doi.org/10.28991/cej-2020-03091510.

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In this paper we present a new solution for the highway interchange, which represents the best compromise between the traffic capacity, the land area used and construction cost. The difference between the known and the new design solution is in the implementation of the opposite directional ramps which are widely separated in the area of the interchange. In the middle, between the directional ramps, some space is created for the left directional ramps. Interchange should be used for four-way highway interchanges or other heavy traffic roads junction in order to increase the capacity and traffic safety at the crossing point. It has no conflict points. ITL Interchange left directional ramps is much shorter than all other known solutions for interchanges. The interchange is built in two levels. These two facts significantly lower the cost of construction. The study compares different types of interchanges. We made a geometric comparison and performance measures. In geometric comparison, the greatest advantages of the ITL interchange are the shortest overall roadway length and the shortest overpasses length. Therefore, such an interchange is advantageous in terms of construction and maintenance costs. When measuring performance, ITL Interchange achieves the best results regardless of the number of vehicles.

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Torbic, Darren J., and Marcus A. Brewer. "Enhanced Design Guidelines for Interchange Loop Ramps." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 39 (2018): 20–33. http://dx.doi.org/10.1177/0361198118758394.

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The objective of this research was to develop improved design guidance for interchange loop ramps. Despite their long use, there is little research on the design, safety, and operational characteristics of loop ramps. An observational field study was conducted to investigate the relationship between speed and lane position of vehicles and design elements of the ramp proper, and differences in performance between single-lane and multi-lane loop ramps. An assessment was also undertaken to determine how well crash prediction methods in the Highway Safety Manual (HSM) represent the safety performance of two ramp types with distinctly different geometrics: loop and diamond ramps. Based on the research results, recommendations regarding the design of the loop ramp proper, applicable at service interchanges are as follows: (a) for a given radius and design speed, recommended lane and shoulder widths for loop ramps are provided that are expected to induce speeds at or below the ramp design speed, result in similar levels of safety, and encourage drivers to stay within their intended travel lane; (b) regarding multi-lane loop ramps, outside lane widths of 12 ft for entrance ramps and 14 ft for exit ramps are sufficient to accommodate traffic comprised primarily of passenger vehicles, but if the outside lane is expected to accommodate moderate to high volumes of trucks, the outside lane width should be increased; and (c) when implementing the HSM ramp crash prediction methodology, calibration factors should be calculated separately for diamond and loop ramps.

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Ran, Bin, Seth Johnson, Shawn Leight, and Jacob H. S. Tsao. "Traffic Analysis for Highway-to-Highway Interchanges on Automated Highway Systems: Congestion in Absence of Dedicated Ramps." Transportation Research Record: Journal of the Transportation Research Board 1588, no. 1 (1997): 145–51. http://dx.doi.org/10.3141/1588-18.

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Special connector ramps linking the automated lanes at automated highway–to–automated highway interchanges may be needed to enable continuous automated driving between two crossing highways. Although a typical cloverleaf configuration has only two levels and is more amenable for such additions, the sharp curvature of this design usually imposes constraints on traffic speed and flow. Because of these constraints, most highway–to–highway interchanges in urban areas have straighter lanes but tend to involve three or more levels. Building the additional connector ramps to accommodate eight high-speed turning movements at an area where the geometry is already complex could be difficult or costly. Therefore, proponents of automated highway systems (AHS) face a major dilemma. This dilemma is studied, including the impact of not providing automated connector ramps on the manual and AHS traffic on manual lanes at or near a highway-to-highway interchange. It is shown that, with a typical cloverleaf design, in the absence of the additional connector ramps, any moderate to heavy AHS-changing traffic could severely disturb the flow of through traffic, seriously exacerbate congestion, and possibly cause a traffic breakdown at the interchange area. These effects will most likely negate any mainline throughput benefits for which an AHS is designed.

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Farah, Haneen, Aries van Beinum, and Winnie Daamen. "Empirical Speed Behavior on Horizontal Ramp Curves in Interchanges in the Netherlands." Transportation Research Record: Journal of the Transportation Research Board 2618, no. 1 (2017): 38–47. http://dx.doi.org/10.3141/2618-04.

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Several studies in the literature have indicated that interchanges are the most crash-prone areas within the motorway system in number and severity of accidents. The reason is the high level of turbulence as a result of vehicle lane changes and speed variability. To understand the safety consequences of an interchange design (e.g., type of connecting ramps, radii and superelevation of curves, and lane and shoulder widths), an in-depth investigation of driving speed behavior is needed. Such an investigation requires the collection of detailed trajectory data on vehicles on different interchanges. These types of data are rarely available, and as a result, such studies are scarce in the literature. The main objective of this present study was to analyze driver speed behavior on different ramps at interchanges, and to develop an operating speed prediction model as a function of the road design elements. Trajectory data on free-moving vehicles were derived from stabilized video images taken from a camera mounted underneath a helicopter, which hovered over the road areas studied. Data were collected from 29 curves at six freeway–freeway interchanges in the Netherlands. The sample included nine direct connections, 12 semidirect connections, and eight indirect connections. The findings showed that speeds were affected by several road geometric characteristics of the curves, by driver expectancy and design consistency, and by the percentage of trucks in traffic. The operating speed prediction models developed in the study will provide designers with tools to estimate the operating speed during the design process.

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Zwahlen, Helmut T., Andrew Russ, and Thomas Schnell. "Viewing Ground-Mounted Diagrammatic Guide Signs Before Entrance Ramps at Night: Driver Eye Scanning Behavior." Transportation Research Record: Journal of the Transportation Research Board 1843, no. 1 (2003): 61–69. http://dx.doi.org/10.3141/1843-08.

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The driver eye scanning study is part of a larger study conducted for the Ohio Department of Transportation to evaluate the effectiveness of ground-mounted diagrammatic guide signs placed before entrance ramps at highway freeway interchanges. This nighttime study investigated driver eye scanning behavior while approaching ground-mounted diagrammatic guide signs placed before entrance ramps. Six highway-freeway interchanges were selected in the Greater Columbus, Ohio, area for placement of the diagrammatic signs in the field. Subjects were six unfamiliar drivers, between the ages of 22 to 42. Two diagrammatic signs were located at each of the six interchanges, .5 mi (805 m) and .25 mi (402 m) before the last point of the gore, where a driver can still gain access to the correct freeway entrance ramp. Driver eye scanning behavior measurements were recorded at night to determine if the presence of the diagrammatic signs elicited an excessive number of eye fixations or was visually distracting to the drivers or both. The results indicate that the diagrammatic signs are not looked at excessively often or excessively long. The average look numbers and average look duration times indicate a normal and reasonable level of information acquisition processing employed by the drivers. These values agree with those previously obtained for regular traffic signing determined in previous eye scanning studies. Ground-mounted diagrammatic signs on multilane arterials in advance of highway freeway interchanges were not demonstrated to unduly distract drivers and detrimentally affect a driver’s looking behavior.

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Abatan, Akinfolarin, and Peter T. Savolainen. "Safety Analysis of Interchange Functional Areas." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 30 (2018): 120–30. http://dx.doi.org/10.1177/0361198118796000.

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Limited access facilities, such as freeways and expressways, are generally designed to the highest standards among public roads. Consequently, these facilities demonstrate crash, injury, and fatality rates that are significantly lower than other road facility types. However, these rates are generally elevated in the immediate vicinity of interchanges because of increases in traffic conflicts precipitated by weaving, merging, and diverging traffic. Given the extensive costs involved in interchange construction, it is important to discern the expected operational and safety impacts of various design alternatives. To this end, the objective of this study was to analyze safety performance within the functional areas of interchanges. The study involves the integration of traffic crash, volume, and roadway geometric data from 2010 to 2014 in the state of Iowa. Separate analyses were conducted for the freeway mainline and ramp connections. A series of safety performance functions (SPFs) were estimated for both the mainline and ramps. Random effects negative binomial models were estimated, which account for correlation in crash counts at the same location over time. The results show the frequency of crashes to vary based on traffic volume, interchange configuration, speed limit, and traffic control at the ramp terminal. The random effects models are shown to significantly outperform pooled models, which suggest there are several important location-specific factors that are not included in the analysis dataset. The SPFs from this study are also compared with several reference models from the extant research literature.

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Sandt, Adrian, Haitham Al-Deek, Md Imrul Kayes, Patrick Blue, and Valentina Gamero. "Benefit–Cost Analyses of Rectangular Flashing Beacon Wrong-Way Driving Countermeasures on Toll Road Exit Ramps in Florida." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 1 (2019): 11–21. http://dx.doi.org/10.1177/0361198119895237.

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In recent years, rectangular flashing beacons (RFBs) and other technologies have been used as wrong-way driving (WWD) countermeasures on limited access facilities. Studies have shown that these devices effectively reduce WWD, but no research has compared the financial benefits and costs of these countermeasures. Three different methodologies were used to conduct benefit–cost analyses for RFB WWD countermeasures installed on Central Florida toll road exit ramps. The studied benefits included savings from reductions in WWD crashes, non-crash events, and injuries, whereas costs included equipment, installation, and maintenance costs. For the first two methodologies, the reduction in WWD crash risk (WWCR) at the RFB-equipped ramps was determined. This WWCR considered non-crash WWD events, interchange design, and traffic volumes. Different measures of effectiveness (turn-around percentage of detected wrong-way vehicles at the RFB ramps and reduction in WWD 911 calls and citations at the RFB interchanges compared with similar comparison interchanges without RFBs) were used in these two methodologies to estimate the WWCR reduction and associated savings. For the third methodology, the relationship between WWD crashes and non-crash events was used to determine the average savings for WWD 911 calls and citations. Before–after analyses were then conducted to determine the individual reductions in WWD 911 calls and citations. Applying these three methods resulted in life-cycle benefit–cost ratios ranging from 2.49 to 4.10 (crash savings) and from 4.77 to 7.20 (injury savings). Other agencies could use these methodologies to determine the benefits of WWD countermeasures or other technologies with limited crash data.

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Zwahlen, Helmut T., Andrew Russ, James M. Roth, and Thomas Schnell. "Effectiveness of Ground-Mounted Diagrammatic Advance Guide Signs for Freeway Entrance Ramps." Transportation Research Record: Journal of the Transportation Research Board 1843, no. 1 (2003): 70–80. http://dx.doi.org/10.3141/1843-09.

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This study investigated the effectiveness of ground-mounted diagrammatic signs in the context of urban multilane arterials leading to freeways. Six highway-freeway interchanges were selected in the greater Columbus, Ohio, area for installation of the diagrammatic signs in the field. The primary measure of effectiveness was the distance at which unfamiliar drivers driving in the wrong lane changed lanes. A total of 21 and 19 test drivers unfamiliar with Columbus roads were recruited for an evaluation before and after installation of the diagrammatic guide signs. This evaluation with unfamiliar test drivers showed that drivers were able to execute a needed lane change earlier when diagrammatic signs were provided. Combining all six sites and looking at the 50th (377 m before, 819 m after) and 85th percentile (203 m before, 601 m after) lane change distances, an increase by a factor of 2.2 to 3.0 between the after and before condition was observed. In addition, a panel of 13 Ohio Department of Transportation and FHWA evaluators visited the six interchange sites and provided their input and opinions on the use of diagrammatic signs. The majority of the evaluators fully embraced the idea of diagrammatic signs. It is suggested that such signs should be used on multilane arterials in advance of highway–freeway interchanges in addition to preexisting guide signs (trailblazer assemblies), in cases in which the cost of overhead span-type sign bridges cannot be economically justified and additional advance guidance information to motorists is highly desirable.

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Chatterjee, Arun, and Frederick J. Wegmann. "Overnight Truck Parking Along Tennessee’s Interstate Highways and Rest Areas." Transportation Research Record: Journal of the Transportation Research Board 1734, no. 1 (2000): 64–68. http://dx.doi.org/10.3141/1734-10.

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Truck parking spaces in the public rest areas and pull-out areas along Tennessee’s Interstate highways are filling up at night, and large trucks are parking along the shoulders of ramps to these areas. Trucks are also parking along regular interchange ramps and in some cases along through lanes. This is a potentially hazardous situation for travelers. A detailed survey was performed at public rest areas in Tennessee at night, covering all 7 days of the week, to learn about the occupancy characteristics of trucks. Availability of space in private truck stops near interchanges also was examined. This research presents the findings of these surveys in quantitative terms. Several truck drivers were interviewed and all neighboring states were contacted to learn more about why some drivers prefer to park along highways and what strategies are being used by other states to alleviate this problem. Findings related to these issues are presented in this research.

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Ismail, Amiruddin, Mojtaba Zourbakhsh, Hamed Eftekhar, Foad Shokri, Aows N.Altef, and Riza Atiq O.K. Rahmat. "An Overview of Interchanges and Ramps in Case of Sabzevar." Research Journal of Applied Sciences, Engineering and Technology 7, no. 6 (2014): 1163–66. http://dx.doi.org/10.19026/rjaset.7.375.

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Bared, Joe G., Alvin Powell, and Evangelos Kaisar. "Traffic Planning Models for Single-Point and Tight Diamond Interchanges." Transportation Research Record: Journal of the Transportation Research Board 1847, no. 1 (2003): 52–57. http://dx.doi.org/10.3141/1847-07.

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Although the single-point interchange (SPI) has been around for approximately three decades, users do not yet have a simplified procedure to evaluate its traffic performance with a similar configuration, the tight diamond interchange (TDI). Several studies have derived general results without decisive conclusions or with partial coverage to assist the users in the selection process. Simulation modeling is used to compare operational traffic performances of isolated SPI and TDI without frontage roads. Modeling was conducted on similar geometries over a wide distribution of traffic flow conditions (101 scenarios). The 101 scenarios were run for both SPI and TDI to derive control delay, stop time, and percent stops from CORSIM. The multivariate statistical comparison of all three variables showed a combined significant difference between the two interchange types, favoring SPI. TDI created more delay, stop time, and percent stops when the left-turn off-ramp flows were very high. Regression models were derived to estimate the three measures for both SPI and TDI. The models are robust and are functions of the highest flows on the cross street and off-ramps. These models are tools that can help planners in the evaluation and selection process of these interchange configurations.

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Behbahani, Hamid, Sayyed Mohsen Hosseini, Alireza Taherkhani, Hemin Asadi, and Seyed Alireza Samerei. "Proposing New Methods to Estimate the Safety Level in Different Parts of Freeway Interchanges." Advances in Civil Engineering 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/8702854.

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Since attention to the safety of traffic facilities including freeway interchanges has been increased during recent years, accident prediction models are being developed. Simulation-based surrogate safety measures (SSMs) have been used in the absence of real collision data. But, obtaining different outputs from different SSMs as safety indicators had led to a complexity of using them as the collision avoidance system basis. Additionally, applying SSM requires trajectory data which can be hardly obtained from video processing or calibrated microsimulations. Estimating safety level in different parts of freeway interchanges through a new proposed method was considered in this paper. Fuzzy logic was applied to combine the outputs of different SSMs, and an index called no-collision potential index (NCPI) was defined. 13608 calibrated simulations were conducted on different ramps, weaving, merge, and diverge areas with different geometrical and traffic characteristics, and NCPI was determined for every case. The geometrical and traffic characteristics formed input data of two safety estimator models developed by Artificial Neural Network and Particle Swarm Optimization. Ten freeway interchanges were investigated to calibrate the simulations and to ensure the validity of the fuzzy method and accuracy of the models. Results showed an appropriate and accurate development of the models.

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Baratian-Ghorghi, Fatemeh, Huaguo Zhou, Mohammad Jalayer, and Mahdi Pour-Rouholamin. "Prediction of Potential Wrong-Way Entries at Exit Ramps of Signalized Partial Cloverleaf Interchanges." Traffic Injury Prevention 16, no. 6 (2014): 599–604. http://dx.doi.org/10.1080/15389588.2014.981651.

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Awad, Wael H., and Bruce N. Janson. "Prediction Models for Truck Accidents at Freeway Ramps in Washington State Using Regression and Artificial Intelligence Techniques." Transportation Research Record: Journal of the Transportation Research Board 1635, no. 1 (1998): 30–36. http://dx.doi.org/10.3141/1635-04.

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Three different modeling approaches were applied to explain truck accidents at interchanges in Washington State during a 27-month period. Three models were developed for each ramp type including linear regression, neural networks, and a hybrid system using fuzzy logic and neural networks. The study showed that linear regression was able to predict accident frequencies that fell within one standard deviation from the overall mean of the dependent variable. However, the coefficient of determination was very low in all cases. The other two artificial intelligence (AI) approaches showed a high level of performance in identifying different patterns of accidents in the training data and presented a better fit when compared to the regression model. However, the ability of these AI models to predict test data that were not included in the training process showed unsatisfactory results.

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Ren, Yuan-Yuan, Xian-Sheng Li, Xue-Lian Zheng, Zhe Li, Qi-Chao Zhao, and Xiao-Xia Chen. "Analysis and Modeling of Driver's Gaze Trajectories in Curves Driving." Advances in Mechanical Engineering 6 (January 2014): 129601. http://dx.doi.org/10.1155/2014/129601.

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To explore the relation between drivers' eye movements and vehicle steering performance, 25 participants were employed to drive a test vehicle on appointed tortuous routes. The drivers' visual behavior was measured while they were driving, and experiment data collected on motorway on-ramps and interchanges were used to analyze the drivers' visual characteristics. The distribution density of the fixation points showed that the drivers paid attention to the inner road edge when turning left and the outer road edge when turning right. Meanwhile, the heights of the gaze targets hardly changed. Therefore, a further investigation discovered that the gaze trajectory was parallel to the vehicle's driving trajectory on one-way curves. Then, six types of gaze trajectories were derived, and models for each type were established. Combining these models with the fact that gaze points are always distributed along the nearby road edge, it was deduced that the starting point of the gaze trajectory when driving on curves has a salient influence on the driver's gaze trajectory.

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Ernzen, Jim, Ginger Murdough, and Debra Drecksel. "Partnering on a Design-Build Project: Making the Three-Way Love Affair Work." Transportation Research Record: Journal of the Transportation Research Board 1712, no. 1 (2000): 202–11. http://dx.doi.org/10.3141/1712-24.

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The partnering process used by the Arizona Department of Transportation in the execution of an $89 million design-build reconstruction of an urban freeway through a congested section of Phoenix is described. The project is changing 6 lanes into 10 lanes by adding a high-occupancy vehicle lane, along with auxiliary lanes, between the entrance and exit ramps over a 13-km (8-mi) stretch of freeway. It involves the demolition and replacement of two bridges that carry major arterial roads over the freeway by using single-point urban interchanges along with several kilometers (miles) of sound walls, new freeway lighting, and an automated freeway management system. Design-build by its nature lends itself to the partnering concept. The partnering concept ideas of increased communication, alignment of goals, and development of a dispute resolution system fit perfectly with design-build’s overarching theme of single-point responsibility for the owner. Increased pressure because of schedule compression typical of most design-build projects makes partnering a vital necessity. Several innovative partnering ideas used on the design-build project to overcome the problems inherent in a complex, high-profile, fast-paced construction project are described.

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Elefteriadou, Lily, Clara Fang, Roger Roess, and Elena Prassas. "Methodology for Evaluating the Operational Performance of Interchange Ramp Terminals." Transportation Research Record: Journal of the Transportation Research Board 1920, no. 1 (2005): 13–24. http://dx.doi.org/10.1177/0361198105192000102.

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Interchange ramp terminals are critical components of the highway network. They provide the connection between various highway facilities (e.g., freeway–arterial and arterial–arterial), and their safe and efficient operation is essential. The objective of this research was to develop improved methods for capacity and quality-of-service analysis of interchange ramp terminals. The research focuses on at-grade intersections but not on the freeway proper. All geometric configurations and interchange types except trumpet interchanges are considered, and the scope of the research includes only signalized interchanges and not “Stop” sign–controlled interchanges and roundabouts. The development of the analytical methodology is primarily based on simulation. The reason for using simulation is that adequate samples of field data are not available, and it is prohibitively expensive to collect them for all types of interchange configurations. The research team assessed several simulation models that were identified as capable of simulating all types of interchange ramp terminals and selected the most appropriate one for model development. Once a simulation model was selected, a variety of interchange configurations were simulated, and selected measures of effectiveness were obtained. Analytical models were developed on the basis of the results of simulation to predict different measures, such as average control delay, volume-to-capacity ratio, and queue-to-storage ratio, for a variety of design and traffic control characteristics.

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Sandt, Adrian, and Haitham Al-Deek. "A Wrong-Way Driving Crash Risk Reduction Approach for Cost-Effective Installation of Advanced Technology Wrong-Way Driving Countermeasures." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 14 (2018): 85–95. http://dx.doi.org/10.1177/0361198118778938.

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Wrong-way driving (WWD) is hazardous on high-speed limited access facilities. Traditional signage and pavement markings will not always prevent intoxicated or confused drivers from entering these facilities the wrong way. To better alert wrong-way drivers, agencies can consider WWD countermeasures equipped with advanced technologies (including warning lights and detection devices) on exit ramps. However, these countermeasures can be expensive for agencies to install on entire roadways or corridors. This paper develops an innovative WWD crash risk (WWCR) reduction approach consisting of a WWCR segment model and an optimization algorithm that can be used to help agencies decide where to install WWD countermeasures. The approach examines segments of limited access facilities to determine the interchanges where advanced technology WWD countermeasures will provide the greatest reduction in WWCR based on an agency’s available resources. A hypothetical example application of this approach is shown for the Central Florida Expressway Authority toll road network. This example shows how the WWCR reduction approach can help agencies identify the optimal investment level and high-risk locations. It also shows how the optimization algorithm can provide significant cost savings compared with equipping entire roadway segments (57% savings) or corridors (83% savings). Agencies can customize the algorithm by adding constraints to represent various scenarios and make the algorithm applicable for networks ranging from single roadways to statewide systems. This WWCR reduction approach could be utilized by agencies nationwide to help them save resources and prioritize investment.

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Li, Zhixia, Madhav V. Chitturi, Andrea R. Bill, and David A. Noyce. "Operational Evaluation of Two-Lane Roundabouts at Freeway Ramp Terminals: Comparison Between Roundabout and Signalized Interchanges." Transportation Research Record: Journal of the Transportation Research Board 2637, no. 1 (2017): 99–113. http://dx.doi.org/10.3141/2637-12.

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In the United States, roundabouts have recently been constructed to replace signalized intersections at freeway ramp terminals as both a safety and an operational treatment. In practice, this treatment is in need of guidelines specifying conditions when the roundabout or signalized intersection is more appropriate to assist practitioners in deciding which alternative to choose. In particular, research providing a comprehensive operational comparison between roundabouts and signalized interchanges is lacking. The current research—though a strictly calibrated microscopic simulation platform—analyzes and models the control delay at double-lane roundabouts and signalized interchanges. Both roundabouts and signalized interchanges were modeled in a Vissim simulation platform. Capacity at each roundabout entrance was calibrated and validated separately for passenger cars and heavy vehicles, since both vehicle types have different critical and follow-up headways. The design of the simulation experiments covered 2,880 different scenarios for roundabouts and signalized interchanges with varying ramp and arterial volumes, ramp spacing, and heavy-vehicle percentages. From the simulation results, control delay and level of service of the off-ramp and arterial approaches of roundabouts and signalized diamond interchanges were modeled and compared. Ultimately, guidelines for the selection between double-lane roundabouts and signalized interchanges were developed and presented in the form of look-up tables. These tables provide an easy-to-use tool for practitioners to determine the appropriate double-lane interchange to install under specific combinations of traffic demand, heavy-vehicle percentage, and ramp spacing conditions.

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Boggs, Alexandra M., Amin Mohamadi Hezaveh, and Christopher R. Cherry. "Shortage of Commercial Vehicle Parking and Truck-Related Interstate Ramp Crashes in Tennessee." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 10 (2019): 153–63. http://dx.doi.org/10.1177/0361198119849586.

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Interstate ramps are the location of more crashes per mile than any other segment of interstate, yet commercial vehicle (CMV) drivers are often left with the last option of parking along these segments for off-duty rest to meet federal hours-of-service regulations. Past literature has evaluated the shortage of CMV parking facilities and examined characteristics of freeway ramp crashes. However, relatively little research has studied the influence of CMV parking deficiency on crash frequency involving parked CMVs along the ramps. This study examined 179 police-reported illegally parked CMV-involved crashes on 1,221 rural and urban ramps in the State of Tennessee, United States. Three Bayesian binary logit models using varying prior distributions were used to analyze the odds of a CMV crash occurring based on CMV parking shortage and ramp attributes. The results illustrated the higher frequency crashes (N = 4 or 5) occurred on entrance ramps of shorter length and often were adjacent to public parking facilities. Approximately one-third of the collisions on interchange ramps had a parking facility utilization rate of 90% or higher, and 23 ramps (15.8%) were adjacent to parking facilities that were at or over-capacity. Several ramp characteristics were significantly associated with an increase in the occurrence of an illegally parked CMV-involved crash and include the presence of a parking facility on exit, ramps with illegally parked CMVs, diamond-shaped ramp configurations, larger ramp shoulder widths, and exit ramps. This study illustrates the impact of the CMV parking shortage on the safety of ramps and highlights the need for more parking facilities.

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Wang, Xiao Ning, and Yu Sheng Ci. "The Relationship between Ramp Length and Traffic Flow Speed (TFS) for Interchange." Advanced Materials Research 243-249 (May 2011): 4386–91. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4386.

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The relationship between ramp length and traffic flow speed (TFS) was studied based on analyzing the design elements of geometry alignment for interchange. After analyzing the process of vehicle running in the ramp, the speed change process was divided into four forms, namely, one deceleration and acceleration process, one deceleration process, one acceleration process and more than one deceleration and acceleration process, and then the relationship between the ramp length and TFS was established respectively. Through an example of the HeDa Interchange of Heilongjiang Province, it showed that although the differences of alignment units of ramps can result in various speeds and specific expressions of relationship between ramp length and TFS. However, all of these relations can be expressed by homologous nonlinear function.

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Tian, Zong, Carroll Messer, Kevin Balke, and Thomas Urbanik. "Integration of Diamond Interchange and Ramp Metering Operations." Transportation Research Record: Journal of the Transportation Research Board 1925, no. 1 (2005): 100–111. http://dx.doi.org/10.1177/0361198105192500111.

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The aim of this research was to develop operational strategies for integrating the operations between diamond interchange traffic signals and ramp metering signals. Integrated operational strategies were developed on the basis of the two commonly used diamond interchange phasing schemes: the basic three-phase scheme and the Texas Transportation Institute four-phase scheme. The key elements of the integration system and its operations include a proposed enhanced detection system and an operational algorithm. Through implementation of special signal timings at the diamond interchange, the traffic flows feeding the ramp meters can be effectively controlled and thus minimize ramp queues and the resulting need to flush the queues, which would possibly lead to freeway breakdown. The operational strategies were evaluated with VISSIM microscopic simulation under three general traffic demand scenarios–-low, medium, and high–-as characterized by the volume-to-capacity ratios at the metered ramps. The results of the evaluation indicated that the integrated operations were most effective under a medium traffic demand scenario in preventing or delaying the onset of ramp metering queue flush, thereby reducing freeway breakdown and system delays.

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Kayes, Md Imrul, Adrian Sandt, Haitham Al-Deek, Nizam Uddin, John H. Rogers, and Grady Carrick. "Modeling Wrong-Way Driving Entries at Limited Access Facility Exit Ramps in Florida." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 8 (2019): 567–76. http://dx.doi.org/10.1177/0361198119845886.

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Wrong-way driving (WWD) is a dangerous behavior which poses a significant safety risk on limited access facilities. As WWD crashes are rare, it is difficult to build credible statistical models based solely on crashes. Modeling other WWD events, such as citations and 911 calls, can result in more reliable models. Even though these WWD events do not always result in a crash, they can be an effective surrogate for WWD crashes. Analysis of Florida limited access exit ramps found that ramps with multiple WWD crashes from 2011 to 2015 tended to have more WWD citations and 911 calls (WWD entries). Additionally, areas with high WWD crash densities also had high WWD entry densities and 68% of WWD crashes had an associated citation, 911 call, or both. These results show that modeling WWD entries can provide insights into WWD crashes. A model was developed for Florida limited access facilities to identify roadway factors and traffic characteristics of exit ramp terminals that influence WWD entries. This model indicated that interchange type, intersection angle of exit ramp terminals, presence of tolling at the entrance ramp, presence of a channelizing island between the exit ramp lanes, number of lanes on the exit ramp, area (rural or urban), and traffic volumes significantly affect the likelihood of WWD entries at exit ramps. With this model, transportation agencies can better predict WWD entries at exit ramps; identify suitable locations for possible countermeasures; and improve their current design, signing, and pavement marking practices while still following national and state standards.

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Xu, Jin, Jinghou Fu, Xiaoming Liu, and Yiming Shao. "Speed Behavior of Passenger Car on Helical Ramps and Helical Bridges in Mountain Riverside City." Journal of Advanced Transportation 2018 (November 13, 2018): 1–17. http://dx.doi.org/10.1155/2018/6752574.

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Helix alignment can allow for a rapid change in road elevation in size-constrained spaces, and it is becoming increasingly popular in interchange design throughout the world. However, driving patterns and vehicle operating characteristics have not been clearly defined on helical ramps. This work conducted field driving tests on four helical ramps located in Chongqing, China. The trajectory, speed, and acceleration of vehicles under normal driving conditions were collected. Thus speed characteristics and speed patterns on helical ramps, as well as their affecting factors, were obtained and analyzed. The findings in this study can provide basic data referencing for designers and engineers, to help them understand how a multilayered helical ramp works, thus to essentially improve the safety level of helix ramps. Moreover, our findings allow bridge designers to understand whether the actual vehicle operating conditions acted in accordance with their expected design requirements, i.e., whether the expected design requirements are achieved.

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BASSAN, Shy. "Empirical modeling of the relationship between decision sight distance and stopping sight distance based on AASHTO." Archives of Transport 4, no. 48 (2018): 7–25. http://dx.doi.org/10.5604/01.3001.0012.8362.

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The paper introduces implementation of highways' stopping sight distance (SSD) and decision sight distance (DSD) based on AASHTO modeling assumptions. SSD characterizes the necessary distance for highway vehicles to stop safely in front from an obstacle. SSD is a function of vehicle speed, perception reaction time, deceleration rate, and grade based on AASHTO and most highway design international guidelines. The deceleration rate which is assumed constant (3.4 m/sec2) based on AASHTO 2011 is generally controlled by the friction coefficient depending on the road surface conditions. A driver's demanded deceleration rate may not exceed the range of friction coefficient according to various pavement conditions. Although SSD is generally sufficient to allow skilled and alert drivers to the stop their vehicles under regular situations, this distance is insufficient when information is difficult to comprehend. A DSD should be provided in highways geometric design when the driver is required to detect an unexpected or difficult to perceive information source. Interchanges (specifically exit ramps) and intersections, and required changing in driver direction of travel, changes in the basic cross section such as toll plaza, lane drop, are typical scenarios where driver needs DSD in the safety manner. The introduction of the two sight distance types (SSD and DSD) is a perquisite for empirical modeling of the relationship between DSD and SSD. The modeling refers to DSD for rural highways, suburban roads, and urban roads based on AASHTO models. Specifically the paper covers DSD three avoidance maneuver types of stopping (types A, A1, B) and three maneuver types of speed, path, and direction changing (types C,D, E) for the three roadway categories. The major parameters that control these avoidance types are pre-maneuver times, and pre-maneuver plus maneuver times. The empirical relationship proposed in this study simplifies the process of evaluating the decision sight distance based on stopping sight distance record, based on AASHTO models, without the need of strenuous estimation of the DSD model maneuver and deceleration parameters. Such a simplified correlation has not been found in the literature except a rough approximation documented in the British highway design guidelines.

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Wang, Xiaofei, Zhenzhong Ding, Kai Guo, and Yongjie Lin. "A Simulation-Based Comprehensive Analysis for Traffic Efficiency and Spatial Distribution of Risks in Short Weaving Area of Municipal Interchange." Journal of Advanced Transportation 2021 (May 19, 2021): 1–14. http://dx.doi.org/10.1155/2021/9968426.

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The weaving area is an important junction that affects the efficiency and traffic safety at the municipal interchanges. To explore the factors affecting traffic efficiency and the spatial distribution characteristics of traffic risks in the weaving areas of municipal interchanges, this study employed a microscopic traffic software of Vissim to construct a simulation model of weaving areas and evaluate the impact of road and traffic design parameters in the short weaving on traffic efficiency and risks, which includes ramp delay, mainline through lane (TL) traffic delay, average ramp speed, TL average speed, and collision rate. Through variance analysis via a large number of simulation scenarios, the weaving length is identified as the most important factor affecting traffic efficiency and risks in the short weaving area. Subsequently, three different types of weaving lengths with 350 m, 450 m, and 550 m were set to conduct the sensitivity analysis based on four performance indexes of mean acceleration and deceleration, acceleration range, deceleration range, and speed standard deviation as the representative variables of spatial risk distribution. The simulation results illustrate that a shorter weaving length has a significant influence on risk distribution, especially the highest risk probability at the positions after three-quarters of the inner and outer lanes in the short weaving area at the municipal interchange. Finally, this study verified the traffic risk reduction method of having traffic safety facilities and traffic organization at the complex interchange with double-entry and single-exit weaving areas in the city of Guangzhou, China. The research proposed a method to analyze the influence of the design parameters in the short weaving area on traffic efficiency and safety and provided a reference for the risk spatial distribution analysis and improvement in the short weaving area.

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Bonneson, James A., and Carroll J. Messer. "Phase Capacity Characteristics for Signalized Interchange and Intersection Approaches." Transportation Research Record: Journal of the Transportation Research Board 1646, no. 1 (1998): 96–105. http://dx.doi.org/10.3141/1646-12.

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Described in this paper are the development, calibration, and application of models that collectively can be used to predict the saturation flow rate and start-up lost time of through movements at signalized interchange ramp terminals and other closely spaced intersections. These models were calibrated with data collected at 12 interchanges. It is concluded that saturation flow rate decreases as the distance to the downstream queue decreases. This queue is formed by the signal at a downstream intersection. Saturation flow rate increases with traffic pressure, as quantified by traffic volume per cycle per lane. It is recommended that an ideal saturation flow rate of 2,000 passenger-car units per hour of green per lane be used for signalized ramp terminals and other high-volume intersections in urban areas. The data collected for this research indicate that start-up lost time increases with saturation flow rate.

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Sun, Jia Feng, Ning Yang, Juan Li, Jing Qiao, and Jian Gang Qiao. "Research on Interchange Ramp Circular Curve Radius Based on Land-Saving Method." Applied Mechanics and Materials 71-78 (July 2011): 4109–14. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.4109.

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As an important part of expressway, interchange has space multi-layer structure form and function of stereoscopic transportation steering, which transforms traffic flow, combs and controls traffic. At present the overpass occupies excessive land and large-scale project, which is serious waste of land resources. Under the premise of ensuring road capacity and traffic safety, in order to save land resource, based on Traffic Engineering, Psychology and other theory, the paper used the method of combination of computer simulation and field experiment, that’s through simulation of a driving simulator cabin got the tensity threshold of driver’s psychological and physiological reaction. Field tests were carried on about cars and drivers on the 68 expressway interchanges in Liaoning and Hubei province by using MC5600, dynamic driver heart physiological tester and other equipments. In addition, the paper surveyed the speed of the vehicle on the road and drivers’ psychological and physiological reaction, constructed mathematical model of driver tensity through analyzing feature point velocity and law of drivers’ psychological and physiological reaction, put forward suggested value of land-saving ramp circular curve radius ensuring traffic safety and service level from the point of speed consistency and driver tensity, which would make expressway interchange design meet the concept of economical highway. Therefore, the paper ensures the quality of highway geometric design as well as improves the effectiveness of highway construction and operation.

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Wang, Xian Guang, and Xiao Nian Sun. "Study on Control Design of Interchange Entrance Congestion Zone." Applied Mechanics and Materials 361-363 (August 2013): 2270–75. http://dx.doi.org/10.4028/www.scientific.net/amm.361-363.2270.

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Interchange entrance area is the key point which affects the overall operational reliability of an Interchange. In order to alleviate the crowded ramp merging area, improve the overall reliability of the interchange and improve traffic safety, when traffic demand increases to a certain extent, traffic control strategies should be used. According of the characteristics of the interchange ramp entrance area, the control strategy of interchange and the mainline which affect the reliability of high-speed road network most has been researched. Analyzing the geometric and traffic characteristics of the ramp merging area, different control strategies on the ramp and the mainline are proposed, that is ramp access control strategy and the main line lane running constraint strategy.

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Le, Thanh Q., and Richard J. Porter. "Safety Evaluation of Geometric Design Criteria for Spacing of Entrance–Exit Ramp Sequence and Use of Auxiliary Lanes." Transportation Research Record: Journal of the Transportation Research Board 2309, no. 1 (2012): 12–20. http://dx.doi.org/10.3141/2309-02.

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Geometric design decisions regarding interchange and ramp spacing on freeways have traditionally taken a nominal approach to safety. This approach oversimplifies driver behavior and complex interactions between roadway geometrics, traffic operations, and safety and tends to promote a one-size-fits-all approach to evaluating design alternatives. The objective of this paper was to quantify the relationship between ramp spacing and freeway safety. Data for this study included freeway geometric features, traffic characteristics, and crash counts for 404 freeway segments in California and Washington State. A negative binomial regression modeling approach was used to explore the relationship between ramp spacing and safety. Results indicated that expected crash frequency increased as ramp spacing decreased. The expected proportion of crashes resulting in a fatality or injury appeared to decrease as ramp spacing decreased. The presence of an auxiliary lane was associated with a lower expected frequency of crashes for any given ramp spacing; the safety benefits of providing an auxiliary lane diminished as ramp spacing increased. The model results related to ramp spacing and the presence of an auxiliary lane were transformed into crash modification factors and validated through comparisons with an independent research study on weaving areas in Texas. The safety findings were generally consistent with current Green Book design criteria related to ramp spacing and the presence of an auxiliary lane. The ability to quantify the expected impact on safety of ramp spacing associated with new or modified interchanges will assist transportation agencies in making well-informed assessments of the overall benefits, impacts, and costs of freeway access decisions.

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Zhang, Chi, Shao Wei Yang, and Min Zhang. "Application of Inverted Function to Alignment Optimization Design of Interchange Ramp." Applied Mechanics and Materials 97-98 (September 2011): 340–46. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.340.

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For adopting to the difficult terrain and restricted conditions, a probability of using the concept of inverted function into interchange linear to optimized design is built, which use the inverted function y=a/x as the interchange right-turn ramp linear. This function can be corresponded to the vehicle trajectory, decrease the area and cut the cost of interchange compared with the ordinary way“spiral-circle-spiral”.By the analysis of how to use this function linear to be ramp, this paper get the way to set the ends of the ramp by circular curve or spiral curve. And this paper also take application example to illustrate the specific solution of how to use the inverted function to set the interchange right-turn ramp.

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Shevtsova, A. G., A. G. Burlutskaya, V. V. Vasilieva, K. V. Levshina, and E. M. Minaeva. "Improving the efficiency of the road junction at the city entrance." MATEC Web of Conferences 329 (2020): 01020. http://dx.doi.org/10.1051/matecconf/202032901020.

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The article is devoted to the study of the method of increasing the capacity at the trans-tailor interchanges providing access to cities, using the example of Belgorod, by introducing the Ramp metering traffic light control system. 4 traffic interchanges at the entrances to the regional center were investigated, geometric parameters of the exits were evaluated. Based on geometric analysis, intensity calculations and time delays, the optimal area for implementing the Ramp metering system is selected.

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Wang, Jin, and Huaguo Zhou. "Using Naturalistic Driving Study Data to Evaluate the Effects of Intersection Balance on Driver Behavior at Partial Cloverleaf Interchange Terminals." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 38 (2018): 255–65. http://dx.doi.org/10.1177/0361198118774670.

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Past studies showed that poor intersection balances at partial cloverleaf (parclo) interchange terminals significantly impact traffic safety and sight distance of drivers making left turns to entrance ramps. Some state traffic agencies have recommended a “balance” guideline that the length between the left-turn stop line on crossroads to the middle of the intersection should not be greater than 60% of the entire length of the intersection. However, a scarcity of research exists on how the balance of an intersection affects driver behavior, which has been identified as a critical contributing factor to intersection-related crashes. This study utilizes the Naturalistic Driving Study (NDS) data to evaluate the effects of intersection balance on driver behavior at parclo interchange terminals for proof-of-concept. A small but representative data sample was collected from the second Strategic Highway Research Program’s (SHRP 2) NDS dataset. It demonstrates statistical characteristics and overall trends of driver speed, acceleration/deceleration rates, and risk perception with the changing of intersection balances. Conclusions provide guidance on optimal intersection balance design that may help drivers make smoother and safer transitions from crossroads to entrance ramps at parclo interchange terminals.

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Wong, S. C., Y. C. Du, H. W. Ho, and L. J. Sun. "Simultaneous Optimization Formulation of a Discrete–Continuous Transportation System." Transportation Research Record: Journal of the Transportation Research Board 1857, no. 1 (2003): 11–20. http://dx.doi.org/10.3141/1857-02.

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Consider a city with a highly compact central business district (CBD) in which commuters’ origins are continuously dispersed. The travel demand is dependent on the total travel cost to the CBD. The transportation system is divided into two layers: major freeways and dense surface streets. Whereas the major freeway network is modeled according to the conventional discrete network approach, the dense surface streets are approximated as a continuum. Travelers to the CBD either travel on the continuum (surface streets) and then exchange to the discrete network (freeways) at an interchange (ramp) before moving to the CBD on the discrete network, or they travel directly to the CBD on the continuum. Specific travel cost–flow relationships for the two layers of transportation facilities are considered. A traffic equilibrium model is developed for this discrete–continuous transportation system in which for a particular origin no traveler can reduce his or her individual travel cost to the CBD by unilaterally changing routes. The problem is formulated as a simultaneous optimization program with two subproblems. One subproblem is a traffic assignment problem from the interchanges to the CBD in the discrete network, and the other is a traffic assignment problem with multiple centers (i.e., the interchange points and the CBD) in the continuous system. A Newtonian algorithm based on the sensitivity analyses of the two subproblems is proposed to solve the resultant simultaneous optimization program. A numerical example is given to demonstrate the effectiveness of the proposed methodology.

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Mansourkhaki, Ali, and Hojat Ghanad. "Optimisation of loop ramp design for cloverleaf interchanges." Proceedings of the Institution of Civil Engineers - Transport 167, no. 4 (2014): 248–58. http://dx.doi.org/10.1680/tran.11.00037.

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Hamad, Khaled, and Abdulkarim Ismail. "Evaluating traffic operations performance of directional interchange with semi-direct ramp connections with loops." Canadian Journal of Civil Engineering 47, no. 4 (2020): 450–60. http://dx.doi.org/10.1139/cjce-2019-0180.

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The purpose of this research is to evaluate the performance of the directional interchange with semi-direct ramp connections with loops (DI-SDRL) in terms of traffic operations under a wide range of traffic demand conditions. Towards this end, the performance of this interchange has been compared with that of a conventional one, i.e., directional with loops interchange (DLI). Thirty different traffic scenarios were developed to test their performance using a state-of-the-art traffic microsimulation tool PTV-VISSIM. The results showed that the DI-SDRL interchange design outperforms the conventional DLI interchange in terms of vehicle hours traveled and mean speed. Nevertheless, the DI-SDRL underperforms the DLI in terms of vehicle kilometres traveled. There was no significant difference in terms of mean delay. At the individual-segment level, the analysis showed that the DI-SDRL interchange outperforms the DLI at diverging segments; in contrast, the DLI interchange outperforms the DI-SDRL at merging segments.

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Herdiana, Alyssa Dewiputri, and Wahju Herijanto. "Kajian Geometrik Interchange Waru Ramp Mojokerto-Sidoarjo." Jurnal Transportasi: Sistem, Material, dan Infrastruktur 2, no. 1 (2019): 16. http://dx.doi.org/10.12962/j26226847.v2i1.5486.

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Li, Shuo, Karen Zhu, Samy Noureldin, and Yi Jiang. "Evaluation of Pavement Friction Performance on Interchange Ramps at Network Level." Journal of Performance of Constructed Facilities 23, no. 2 (2009): 109–14. http://dx.doi.org/10.1061/(asce)0887-3828(2009)23:2(109).

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Wang, Ling, and Mohamed Abdel-Aty. "Microscopic Safety Evaluation and Prediction for Freeway-to-Freeway Interchange Ramps." Transportation Research Record: Journal of the Transportation Research Board 2583, no. 1 (2016): 56–64. http://dx.doi.org/10.3141/2583-08.

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Atiquzzaman, Md, and Huaguo Zhou. "Modeling the Risk of Wrong-Way Driving Entry at the Exit Ramp Terminals of Full Diamond Interchanges." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 17 (2018): 35–47. http://dx.doi.org/10.1177/0361198118783152.

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Wrong-way driving (WWD) crashes are a critical safety issue on freeways. Although these crashes are rare and random in nature, they often result in severe injuries and/or fatalities. Typically, exit ramp terminals are the initial point of entry for wrong-way (WW) drivers on freeways. Therefore, it is important for transportation agencies to identify the exit ramp terminals with higher possibility of WW entries and apply safety countermeasures to reduce the chances of their occurrence. However, the random nature of WWD crashes and the difficulty in identifying the actual entry points makes it hard for transportation agencies to assess the risk of WWD at a particular exit ramp terminal and apply countermeasures accordingly. This study developed mathematical models for predicting the risk of WW entries at the exit ramp terminals of full diamond interchanges. The geometric design features, usage of traffic control devices, area type where the interchanges are located, and annual average daily traffic (AADT) at the exit ramp terminals with or without history of WWD were used as potential predictors of WW entry. Transportation agencies can use these models to assess the risk of WW entries at the exit ramp terminals within their jurisdictions and consider possible countermeasures. They also can be applied during the design phase to determine the combination of geometric design features and traffic control devices that ensures the least possibility of WW entry.

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Zhao, Qing Yun, Lei Wang, Shi Hua Yu, Zhi Qiang Lu, and Yue Long Sun. "Study on the Static and Dynamic Load Test of Ramp Bridge." Applied Mechanics and Materials 361-363 (August 2013): 1101–4. http://dx.doi.org/10.4028/www.scientific.net/amm.361-363.1101.

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Ramp bridges are usually curved girder bridges, and show unique mechanical characteristics under live load. On the basis of an interchange ramp bridge static and dynamic load test in a radius of 230m, the bridges stress, deflection and dynamic characteristics were analyzed and the bearing capacity was evaluated.

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Bonneson, James A., and Karl Zimmerman. "Interchange Critical Movement Analysis for Planning and Preliminary Design Applications." Transportation Research Record: Journal of the Transportation Research Board 1920, no. 1 (2005): 1–12. http://dx.doi.org/10.1177/0361198105192000101.

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A procedure that can be used to compare a variety of common interchange types or make decisions about their design is described. The technique is based on the critical movement analysis approach traditionally used for signalized intersection analysis. This approach defines the rules for quantifying the sum of critical flow ratios for various interchange types. The concept of interchange delay is defined, and an equation for quantifying it is described. Simulation data are used to calibrate a series of models that relate the sum of critical flow ratio to interchange delay. A procedure that describes how these models can be used to obtain a quick estimate of the delay associated with a particular interchange type, given specific volume levels, lane assignments, and ramp separation distances, is documented.

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Chandra, Vijay, Anthony L. Ricci, Paul J. Towell, and Keith Donington. "Landmark Cable-Stayed Bridge over the Charles River, Boston, Massachusetts." Transportation Research Record: Journal of the Transportation Research Board 1845, no. 1 (2003): 19–27. http://dx.doi.org/10.3141/1845-03.

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Boston, in the forefront of the American Revolution two centuries ago, is now in the forefront of another revolution in the field of cable-stayed bridge technology. New technologies and innovations have become hallmarks of the Leonard P. Zakim Bunker Hill Bridge—a structure unique in the world. This crossing of the Charles River brought the community, engineers, and architects together to create a “signature bridge” and a “gateway” to the city. Located at a preeminent point where Paul Revere crossed in 1775, the bridge took on special meaning from a historical perspective. Numerous alternatives were studied for the crossing and the interchange configurations on both sides of the river. Based on significant community input and evaluation of costs for different alternatives, the option known as the “non-river tunnel” alternative was chosen, which required a 10-lane crossing of the river. The 10 lanes include 4 lanes each for I-93 northbound and southbound and a 2-lane ramp on the east side. Some impediments the bridge had to contend with included the Orange Line subway adjacent to and below the bridge; the close proximity of the Charles River lock and dam and the need to maintain navigation; a major water main in the area of the south tower footing; a cantilevered 2-lane ramp on only one side of the structure; the existing Storrow Drive ramps at the south end, dictating the arrangement of the stay cables in the back spans; and a new tunnel at the south end of the structure.

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Messer, Carroll J. "Extension and Application of Prosser-Dunne Model to Traffic Operation Analysis of Oversaturated, Closely Spaced Signalized Intersections." Transportation Research Record: Journal of the Transportation Research Board 1646, no. 1 (1998): 106–14. http://dx.doi.org/10.3141/1646-13.

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Traffic congestion continues to have a serious impact on the productivity of the nation’s transportation system. Signalized arterials and service interchanges in urban areas serve as critical surface street facilities. These facilities often experience serious congestion problems because of high traffic demands that exceed capacity and also because of their common, closely spaced intersections and ramp terminals. Moreover, service interchanges are usually part of a signalized cross arterial and also may have short spacings to adjacent signalized intersections. Major deficiencies exist in the analysis technology and software tools available for analyzing potential traffic congestion problems at signalized arterials and service interchanges having closely spaced ramp terminals. This paper presents extensions of work originally published by Prosser and Dunne in Australia for analyzing the operational impacts of queue spillback on the capacity and delay of closely spaced signalized intersections. Coding of the described algorithm into FORTRAN was conducted, followed by experimental testing of the model using a calibrated version of the microscopic computer simulation program TRAF-NETSIM. Satisfactory comparisons were obtained between the initial version of the newly developed Prosser-Dunne Extended (PDX) model and NETSIM, but more testing and enhancement of the PDX model are recommended before implementation in existing operational software packages is considered.

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Liapis, Evangelos D., Basil Psarianos, and Eva Kasapi. "Speed Behavior Analysis at Curved Ramp Sections of Minor Interchanges." Transportation Research Record: Journal of the Transportation Research Board 1751, no. 1 (2001): 35–43. http://dx.doi.org/10.3141/1751-05.

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Claros, Boris, Praveen Edara, and Carlos Sun. "Safety Effect of Diverging Diamond Interchanges on Adjacent Roadway Facilities." Transportation Research Record: Journal of the Transportation Research Board 2618, no. 1 (2017): 78–90. http://dx.doi.org/10.3141/2618-08.

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Recent evidence has shown that the diverging diamond interchange (DDI) design improves the safety of the ramp terminals and the overall safety of the interchange. What is still not known is the safety effect that a DDI has on adjacent intersections and the speed-change lanes (SCLs) at freeway entrances and exits. This study addressed this void by examining DDI installations in Missouri. The early and many DDI implementations in Missouri provided a rich data set with which to conduct this study. Twelve major signalized intersections adjacent to the DDI ramp terminals were examined. Thirty-two SCL facilities, 16 freeway entrances, and 16 exits from 11 DDI sites also were examined. A manual review was done to assign 4,073 crash reports to corresponding facilities. The empirical Bayes (EB) method was used to estimate the safety effect of the DDI on adjacent facilities. No evidence showed that the DDI design had any effect, positive or negative, on the crashes that occurred at the entrance or exit SCLs. After DDI implementation, the changes were not statistically significant for SCL crash frequency, property damage only (PDO) crashes, and total crashes. For signalized intersections next to the DDI ramp terminals, the EB analysis showed a 6.5% decrease in fatalities and injuries, which was not statistically significant. The analysis also showed a 19.5% increase in PDO and a 12% increase in total crashes, albeit statistically significant only at the 90% confidence level. In summary, no strong evidence was found that DDIs affected safety, either negatively or positively, on adjacent SCLs or intersections.

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Jun Xie, Hua Chai. "A Geometry Elements Based Speed Prediction Model for Interchange Ramps of Mountainous Motorways." IOP Conference Series: Earth and Environmental Science 267 (June 8, 2019): 042008. http://dx.doi.org/10.1088/1755-1315/267/4/042008.

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Zhang, Xian Feng. "Research of Design and Construction Key Technology of Underwater Tunnel Interchange Segment." Applied Mechanics and Materials 501-504 (January 2014): 1647–52. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1647.

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By Changsha Xiangjiang River Camp Road tunnel geological conditions and the overall analysis, the paper proposed the overall and the inner contour design of the underwater tunnel interchange segment .Establishing calculation model of the north-south main line and C, D segments interchange ramp, and using ANSYS finite element software to calculate and determine the design parameters of the tunnel cross-section . For the upper and lower layers tunnel use excavation construction, and applying the Center-Cross-Diaphragm (CRD) method to tunneling.

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Messer, Carroll J. "Simulation Studies of Traffic Operations at Oversaturated, Closely Spaced Signalized Intersections." Transportation Research Record: Journal of the Transportation Research Board 1646, no. 1 (1998): 115–23. http://dx.doi.org/10.3141/1646-14.

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Traffic congestion continues to have a serious impact on the productivity of the nation’s transportation system. Signalized service interchanges in urban areas serve as a critical connection between freeway and arterial surface street systems. These facilities often experience serious congestion problems because of high traffic demands exceeding capacity and because of their common, closely spaced ramp terminals. Moreover, service interchanges are usually a part of a signalized cross arterial and may also have short spacings to adjacent signalized intersections. Major deficiencies exist in the analysis technology and software tools available for analyzing traffic congestion problems at oversaturated signalized interchanges and closely spaced arterial systems. Results are provided of an investigation into the nature of oversaturated systems and also undersaturated systems that may become congested (oversaturated) because of poor signal timing and deficient spacing between the signalized intersections. Although the initial research focus was on signalized service interchanges based on calibrated NETSIM simulations, the research results are also applicable to closely spaced signalized urban arterials. The research shows that traffic congestion is complex, but it can be characterized and modeled. An upper bound on signal control delay is provided for oversaturated arterial operations.

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Journal articles on the topic 'Ramps (Interchanges)'

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