Author: Kyung-Whan KimPublisher:
ISBN:
Category :
Languages : en
Pages : 228
Book Description
Development of Warrants for Left-turn Lanes at Unsignalized Intersections in Korea
Author: Kyung-Whan KimDevelopment of Left-turn Lane Warrants for Unsignalized Intersections
Author: Publisher:
ISBN:
Category : Left-turn lanes
Languages : en
Pages :
Book Description
Left-turn movements at intersections, including driveways - especially movements that are made from lanes that are shared with through traffic - cause delays and adversely impact safety. Although left-turn warrants have been updated, many agencies still use research performed by M. Harmelink from the mid-1960s. While most states use procedures that are based on Harmelink, a number of limitations of Harmelink's procedure have been identified. Economic analysis can provide a useful method for combining traffic operations and safety benefits of left-turn lanes to identify situations in which left-turn lanes are and are not justified economically. This project used a benefit-cost approach to determine when a left-turn lane would be justified. The steps included simulation to determine delay savings from installing a left-turn lane, crash costs and crash reduction savings determined from safety performance functions and accident modification factors available in the "Highway Safety Manual," and construction costs. Left-turn lane warrants were developed for rural two-lane highways, rural four-lane highways, and urban and suburban roadways. In addition, warrants for bypass lanes were developed for rural two-lane highways. A "Design Guide on Left-Turn Accommodations at Unsignalized Intersections" was developed that discusses left-turn lane designs, traffic control treatments, and case study examples.
Development of Warrants for Installation of Dual Right-turn Lanes at Signalized Intersections
Author: Yi QiPublisher:
ISBN:
Category : Right-turn lanes
Languages : en
Pages : 126
Book Description
Right-turn lanes provide space for the deceleration and storage of right-turn vehicles, and separate turning vehicles from through movements. Dual right-turn lanes are increasingly used at urban intersections primarily for two reasons: (1) to accommodate high right-turn demands and avoid turn-pocket overflows, and/or (2) to prevent right-turn vehicles that exit from a nearby upstream freeway off-ramp (on the left of the roadway) from abruptly changing too many lanes toward the right-turn lane at the intersection. In addition, a number of other factors may affect the decisions on the installation of dual right-turn lanes. However, warrants for dual right lane installation are almost non-existent, leaving traffic engineers to rely on engineering judgment. This research aims to develop warrants for installation of dual right-turn lanes at signalized intersections. Both the operational and safety benefits/costs were analyzed by surveying traffic engineers and by conducting traffic simulation-based analysis. Microscopic traffic simulation model, VISSIM, was used to quantify the operation benefits and Surrogate Safety Assessment Model (SSAM) developed by Siemens was used to analyze the safety gains due to installation of dual right-turn lanes.
Development of Warrants for Left-turn Lanes
Author: Kenneth R. AgentPublisher:
ISBN:
Category : Road markings
Languages : en
Pages : 44
Book Description
Volume Warrants for Left-turn Lanes at Unsignalized Grade Intersections
Author: M. D. HarmelinkPublisher:
ISBN:
Category : Left-turn lanes
Languages : en
Pages : 72
Book Description
Development of Warrants for Left-turn Phasing
Author: Kenneth R. AgentPublisher:
ISBN:
Category : Electronic traffic controls
Languages : en
Pages : 48
Book Description
A Decision Support System and New Warrants for Left Turn Lane Installation at Unsignalised Intersections
Author: Sarang S. RanadePublisher:
ISBN:
Category :
Languages : en
Pages : 238
Book Description
Accommodating left turns at un-signalized intersections is one of the most challenging problems in traffic engineering. Over the last forty years, a small number of studies developed guidelines for traffic engineers to help decide when a left turn lane is warranted for a given situation. Building on these previous attempts, the current study not only develops warrants for the left turn lane at an unsignalised intersection but also a refined decision support system (DSS) for assessing the likely benefits of left-turn lane installations. The developed warrants use total delay (veh.sec/hour) and total stops (number) on the subject link as the warrant criteria, and the trigger level differs by road category. The developed DSS on the other hand, is designed to predict the likely benefits of installation of an exclusive left turn lane at an un-signalized intersection. The benefits are measured in terms of delay savings, reductions in the total number of stops, increases in fuel efficiency, and reductions in emissions. The first step in developing the left turn lane warrants and the DSS was to use microscopic simulation to model several real-world un-signalized intersections with different geometric. After carefully calibrating these models, several scenarios which cover a wide range of operational conditions (opposing, advancing, left turning volumes speed etc,) were simulated. The output fiom these simulation runs was then used to train a set of Multi-layer Perceptron Neural Networks (NNs), and to generalize the results from the models' runs. These NNs can therefore serve as a DSS for predicting the likely benefits of left turn lane installations. In addition, new warrants were developed for left turn lane installations based on delay as well as percent stops as warrant criteria.
Development of Warrants for Right-turn Treatments at Unsignalized Intersections
Author: Tanweer HasanWarrants for Exclusive Left Turn Lanes at Unsignalized Intersections and Driveways
Author: Volume Warrant for Free Right-turn Lanes at Unsignalized Intersections on Rural Two-lane Highways
Author: Patrick T. McCoyPublisher:
ISBN:
Category : Roads
Languages : en
Pages : 33
Book Description