Author: Fred L. Mannering
Publisher:
ISBN:
Category : Speed limits
Languages : en
Pages : 188

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Author: Michael C. Zavoina
Publisher:
ISBN:
Category : Interstate Highway System
Languages : en
Pages : 158

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Book Description
With the increased expansion of rural Interstates to six lanes, questions have arisen as to the proper operational strategy of those facilities. One approach is to restrict trucks and other large vehicles from one or more of the lanes. The effects of such a restriction, however, have not been extensively studied. This study analyzes the operational effects of three left-lane truck restrictions on six-lane rural Interstates in Texas. Although the directional distribution of trucks changed significantly, no effects were found on the directional distribution of cars, the time gaps between vehicles, or the speeds of either cars or trucks that could be attributed to the truck restriction.

Author: National Research Council (U.S.). Transportation Research Board
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 284

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Author:
Publisher:
ISBN:
Category : Air travel
Languages : en
Pages : 616

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Author:
Publisher:
ISBN:
Category : Transportation, Automotive
Languages : en
Pages : 274

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Author: National Research Council (U.S.). Transportation Research Board
Publisher:
ISBN:
Category : Electronic traffic controls
Languages : en
Pages : 256

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Book Description
TRB?s Transportation Research Record: Journal of the Transportation Research Board 1867 examines several algorithms that estimate speed from traffic surveillance cameras in a variety of traffic, weather, and lighting conditions; identify bottleneck locations, the active times, and the delays that are caused; and are applied to the archived loop detector data in the I-4 data warehouse.

Author: Lester A. Hoel
Publisher:
ISBN:
Category : Express highways
Languages : en
Pages : 38

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Book Description
In recent years, increases in truck traffic on Virginia's highways have raised issues concerning safety and capacity on interstates such as I-81 and I-95. Lane restrictions represent a strategy that is intended to reduce conflicts between trucks and cars and facilitate traffic flow. Field experiments to determine the effects on existing traffic under lane restrictions for an interstate freeway segment are usually not feasible, and an alternative approach was selected. In this study, the simulation model FRESIM was used to estimate various traffic flow elements. The purpose of this study was to analyze changes in traffic flow elements (density, lane changes per vehicle, and speed differential) under conditions of restricted and unrestricted truck lane configurations. Prior to application of the simulation model to actual sites in Virginia, a scenario analysis was completed. The scenario analysis tested the variability of each traffic flow element considering the following variables: traffic volume, percentage of trucks, percentage of total volume by lane, presence or absence of lane restrictions, and grade. A statistical paired-sample t test was used to determine significant differences in the values of the three traffic flow elements when lane restrictions were applied. An analysis was also completed for three case studies in Virginia, located on I-81 near Buchanan, Christiansburg, and Wytheville. Two types of restrictions were tested: restricting trucks from the left lane and restricting trucks from the right lane. From the results obtained in this study several conclusions were drawn: (1) restricting trucks from the left lane with steep grades causes an increase in speed differential and may decrease density and the number of lane changes, (2) restricting trucks from the right lane causes an increase in the number of lane changes, and (3) site characteristics dictate the effects of truck lane restrictions. Based on the results of this study, it is recommended that (1) trucks be restricted from the left lane when grades are 4 percent or greater and (2) trucks not be restricted from the right lane. The study results did not support removal of truck lane restrictions in Virginia.

Author:
Publisher:
ISBN:
Category : Express highways
Languages : en
Pages : 528

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Author: Renatus Mussa
Publisher:
ISBN:
Category : Express highways
Languages : en
Pages : 226

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Book Description

Author: Michael D. Fontaine
Publisher:
ISBN:
Category : Traffic safety
Languages : en
Pages : 34

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Book Description
In response to a request by Frank S. Wolf and Jo Ann Davis of the U.S. House of Representatives, Governor Mark Warner formed a Special Task Force on Truck Safety in the fall of 2002. The objective of the task force was to examine ways to reduce the number of crashes involving large trucks on Virginia's roads. One of the goals of this task force was to identify engineering and technology measures that have the potential to improve large truck safety. The task force charged the Virginia Transportation Research Council with identifying engineering and technology measures that offer the potential to improve large truck safety. A literature review of these areas was conducted, and a survey of personnel in the Virginia Department of Transportation (VDOT) was also carried out (1) to determine what measures have been implemented in Virginia, and (2) to solicit ideas for additional improvements. Traffic control improvements, geometric design changes, and intelligent transportation systems that improve truck safety are summarized in this report, and survey respondents. Recommendations for potential initiatives in engineering, enforcement, and education are also presented. The research showed that VDOT has already taken many actions to improve large truck safety issues and that further action could be taken in several areas: 1. VDOT's Mobility Management Division (MMD) should consider encouraging the use of dynamic truck speed advisory systems on freeway ramps where there are large numbers of rollover crashes. 2. VDOT's Location & Design Division should examine whether current design standards are adequate for the current truck fleet. 3. The MMD should consider developing guidelines for providing advance warning of the start of the red phase at intersections with limited sight distance. 4. The MMD should reexamine whether the truck lane restrictions are producing safety improvements. In addition to these measures, VDOT should continue to pursue the initiatives that are already underway, for example, the rumble strip program and measures to improve traveler information.