Citation

Eccles K, Himes S, Peach K, Gross F, Porter RJ, Gates TJ, Monsere CM. NCHRP Res Rep. 2018; (875): 1-44.

Copyright

(Copyright © 2018, National Cooperative Highway Research Program (NCHRP); National Academies Press)

DOI

10.17226/25081

PMID

unavailable

Abstract

NCHRP Research Report 875: Guidance for Evaluating the Safety Impacts of Intersection Sight Distance is a resource for practitioners involved in the planning, design, operations, and traffic safety management of stop-controlled intersections. It provides information on how to estimate the effect of intersection sight distance (ISD) on crash frequency at intersections and describes data collection methods and analysis steps for making safetyinformed decisions about ISD. The guidance also provides basic information on the importance of ISD that can be shared with decision makers and other stakeholders.

Accompanying the report, NCHRP Web-Only Document 228: Safety Impacts of Intersection Sight Distance documents the methodology and presents the results from the underlying research on estimating the safety effects of ISD at stop-controlled intersections. To establish the relationship between ISD and safety at stop-controlled intersections, crash, traffic, and geometric data were collected for 832 intersection approaches with minorroad stop control in North Carolina, Ohio, and Washington.

The provision of appropriate ISD is an important element in intersection design. The approach to the determination of ISD in AASHTO's A Policy on Geometric Design of Highways and Streets (known as the "Green Book") is based on gap-acceptance developed in the 1996 NCHRP Report 383: Intersection Sight Distance. That approach includes the ability to more easily calculate ISD for both passenger cars and trucks by allowing the selection of an ISD "design vehicle." Calculations of ISD using that approach yield different results from those calculated with earlier methods. However, past research efforts to analyze and quantify the safety impacts of ISD have produced inconsistent results, making it difficult to fully evaluate the different approaches. The quantification of safety impacts allows better design evaluations that include variations in available ISD. It also provides the opportunity to evaluate the potential safety impacts of the ISD criteria in the Green Book...

Language: en