Guidelines for the Inclusion of Left-Turn Lanes at Rural Highway Intersections, HR-147, 1970

(1970) Guidelines for the Inclusion of Left-Turn Lanes at Rural Highway Intersections, HR-147, 1970. Transportation, Department of

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Abstract

Provision of left turn lanes is a major problem which lacks an objective approach. Various techniques and procedures in use have been reviewed. Traffic characteristics at typical Iowa intersections have been measured. A rational approach for inclusion of a left turn lane has been developed, based on relating the benefits to the road user to the cost of providing the added turing lane. An analysis of field data gathered under this project indicates that the use of theoretical distribution to describe vehicle headways is not applicable to rural Iowa two lane roads. As an alternate approach the mass of field data gathered were examined using multiple regression techniques to yield equations for predicting stops and delays. The benefit-cost ratio technique is recommended as the criterion for decision making.

Item Type: Departmental Report
Keywords: Benefit cost analysis, Left turns, Multiple regression analysis, Regulatory signs, Rural highways, Traffic flow
Subjects: Transportation
Transportation > Traffic Management
Transportation > Roads and highways
Transportation > Law and policies
Transportation > Law and policies > Enforcement
ID Code: 21987
Deposited By: Iowa DOT Library
Deposited On: 29 Apr 2016 15:22
Last Modified: 29 Apr 2016 15:22
URI: http://publications.iowa.gov/id/eprint/21987