Exploring the Potential of Combining Ramp Metering and Variable Speed Limit Strategies for Alleviating Real-time Crash Risk on Urban Freeways PDF Download
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Author: Kirolos Maged Haleem Publisher: ISBN: Category : Languages : en Pages : 389
Book Description
In summary, Ramp Metering was more beneficial at congested situations, while Variable Speed Limits were more beneficial at free-flow conditions. At conditions approaching congestion, the combination of Ramp Metering and Variable Speed Limits produced the best benefits. These results illustrate the significant potential of ITS strategies to improve the safety and efficiency of urban freeways.
Author: Kirolos Maged Haleem Publisher: ISBN: Category : Languages : en Pages : 389
Book Description
In summary, Ramp Metering was more beneficial at congested situations, while Variable Speed Limits were more beneficial at free-flow conditions. At conditions approaching congestion, the combination of Ramp Metering and Variable Speed Limits produced the best benefits. These results illustrate the significant potential of ITS strategies to improve the safety and efficiency of urban freeways.
Author: Vikash V. Gayah Publisher: ISBN: Category : Languages : en Pages : 267
Book Description
It should also be noted that both route diversion and ramp metering were found to increase the overall network travel time. However, the best route diversion and ramp metering strategies were selected to ensure that the operational capabilities of the network were not sacrificed in order to increase the safety along the freeway. This was done by setting the maximum allowable travel time increase at 5% for any of the ITS strategies considered.
Author: Albinder Singh Dhindsa Publisher: ISBN: Category : Adaptive control systems Languages : en Pages : 220
Book Description
Recent research at UCF into defining surrogate measures for identifying crash prone conditions on freeways has led to the introduction of several statistical models which can flag such conditions with a good degree of accuracy. Outputs from these models have the potential to be used as real-time safety measures on freeways. They may also act as the basis for the evaluation of several intervention strategies that might help in the mitigation of risk of crashes.
Author: Ryan J. Cunningham Publisher: ISBN: Category : Intelligent transportation systems Languages : en Pages : 231
Book Description
In the free-flow condition (60% loading), the best treatments involved the more liberal threshold for defining homogeneous speed zones (5 mph) and the more liberal implementation distance (entire speed zone), as well as a minimum time period of 10 minutes. This treatment was actually shown to significantly reduce the network travel time by 0.8%. It was also shown that this particular implementation strategy (lowering upstream, raising downstream) is wholly resistant to the effects of crash migration in the 60% loading scenario. In the condition approaching congestion (80% loading), the best treatment again involved the more liberal threshold for homogeneous speed zones (5 mph), yet the more conservative implementation distance (half the speed zone), along with a minimum time period of 5 minutes. This particular treatment arose as the best due to its unique capability to resist the increasing effects of crash migration in the 80% loading scenario. It was shown that the treatments implementing over half the speed zone were more robust against crash migration than other treatments. The best treatment exemplified the greatest benefit in reduced sections and the greatest resistance to crash migration in other sections. In the 80% loading scenario, the best treatment increased the network travel time by less than 0.4%, which is deemed acceptable. No treatment was found to successfully reduce the rear-end and lane-change crash risks in the congested traffic condition (90% loading). This is attributed to the fact that, in the congested state, the speed of vehicles is subject to the surrounding traffic conditions and not to the posted speed limit. Therefore, changing the posted speed limit does not affect the speed of vehicles in a desirable manner. These conclusions agree with Dilmore (2005).
Author: Carroll J. Messer Publisher: ISBN: Category : Electronic traffic controls Languages : en Pages : 114
Book Description
Freeway ramp metering systems have been used to improve urban freeway flow. However, control strategies must be properly adjusted to account for ramp queues overflowing onto surface streets and provide equitable on-ramp control during various operating periods. An improved solution can be obtained by optimizing this problem simultaneously for a group of time slices. This study identifies and examines a microcomputer-based optimization scheme that can assist in developing efficient freeway control strategies for on-line freeway surveillance and control. A multi-level freeway control structure is employed for which ramp metering control algorithms are developed for each level of control. Flow-based and lane occupancy-based system algorithms are presented. Detailed data file requirements are provided for each control level. A microcomputer prototype, or laboratory test version of the system level, will be described in a companion project report.
Author: Publisher: Transportation Research Board ISBN: 9780309065023 Category : Business & Economics Languages : en Pages : 444
Book Description
TRB Special Report 254 - Managing Speed: Review of Current Practices for Setting and Enforcing Speed Limits reviews practices for setting and enforcing speed limits on all types of roads and provides guidance to state and local governments on appropriate methods of setting speed limits and related enforcement strategies. Following an executive summary, the report is presented in six chapters and five appendices.
Author: Peter Eric Allaby Publisher: University of Waterloo ISBN: 9780494233702 Category : Languages : en Pages : 171
Book Description
The objectives of this thesis are: (1) to validate a real-time crash prediction model for a candidate section of freeway; (2) to develop a candidate VSLS control algorithm with potential for practical applications; (3) to evaluate the performance of the VSLS control strategy for a range of traffic conditions in terms of safety and travel time; and (4) to test the sensitivity of the VSLS impact results to modifications of the control algorithm.
Author: Kirolos Maged Haleem
Author: Kirolos Maged Haleem
Author: Vikash V. Gayah
Author: Albinder Singh Dhindsa
Author: Ryan J. Cunningham
Author: Carroll J. Messer
Author: 
Author: Peter Eric Allaby
Author: Xiao-Yun Lu
Author: Menahem Eldor
Author: