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Title:

Left-Turn Prohibition and Partial Grade Separation for Signalized Intersections: Planning-Level Assessment

Accession Number:

01368414

Record Type:

Component

Availability:

Transportation Research Board Business Office

500 Fifth Street, NW
Washington, DC 20001 USA
Order URL: http://amonline.trb.org/

Abstract:

The congestion of urban signalized intersections is a major issue, even in cities where advanced traffic signal timing and management systems are in operation. Recurring congestion at signalized intersections is usually caused by the inability of traffic signal controls to serve demand. Left turn prohibition and partial grade separation (low-clearance underpass) are discussed as possible solutions for urban complex and congested signalized intersections that have exhausted other methods for capacity enhancement. Both treatments potentially improve traffic signal efficiency by eliminating or reducing the duration of signal phases, and enhance intersection safety by eliminating certain conflicts. At the same time, they necessitate rerouting of traffic and have implication with respect to accessibility, land values, lane utilization, etc. A planning-level assessment method to quantify and compare the benefits and costs of these treatments has been developed. The assessment considers the direct effects on intersection delay (using the Highway Capacity Manual 2010 methods) and accident frequency (using the Highway Safety Manual crash prediction methodology) and includes a cost-benefit analysis based on AASHTO’S User Benefit Analysis for Highways Manual. The objective of the planning level assessment is to be substantially comprehensive while using as many nationally accepted default values and conservative assumptions to minimize workload and expedite assessment at multiple locations. Due to the complexity of these layers of analysis for multiple treatments and time periods, a spreadsheet-based computational tool was developed and a case study was used to demonstrate the assessment method.

Supplemental Notes:

This paper was sponsored by TRB committee AHB65 Operational Effects of Geometrics

Monograph Accession #:

01362476

Report Numbers:

12-0324

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 USA

Authors:

Yu, Xin
Prevedouros, Panos D

Pagination:

26p

Publication Date:

2012

Conference:

Transportation Research Board 91st Annual Meeting

Location: Washington DC
Date: 2012-1-22 to 2012-1-26
Sponsors: Transportation Research Board

Media Type:

Digital/other

Features:

Figures; References; Tables

Subject Areas:

Highways; Operations and Traffic Management; I73: Traffic Control

Source Data:

Transportation Research Board Annual Meeting 2012 Paper #12-0324

Files:

TRIS, TRB

Last Modified:

Apr 25 2012 8:00AM