NEW! 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 safety informed decisions about ISD.
TRB's National Cooperative Highway Research Program (NCHRP) has released a pre-publication, non-edited version of Research Report 855: An Expanded Functional Classification System for Highways and Streets. This report builds upon preliminary engineering of a design project, including developing the purpose and need. In particular, it provides additional contexts beyond urban and rural, facilitates accommodation of modes other than personal vehicles and adds overlays for transit and freight.
This digest summarizes findings of National Cooperative Highway Research Program (NCHRP) Project 3-52A, "Impacts of Access-Management Techniques." NCHRP Report 420, "Impacts of Access Management Techniques" (1999), presents relationships between access density and accident rates. This digest uses additional data from Minnesota to confirm these relationships. The digest is organized as follows: Introduction; Problem Statement; Objective and Approach; Background; Results; Comparisons; and Accident Rate Indices.
TRB's NCHRP Synthesis 348: Improving the Safety of Older Road Users examines programs and policies in place across the country to improve the safety and mobility of older road users. The report documents a range of strategies and related programs under way in roadway engineering, driver licensing, public information and education, and enforcement and adjudication.
This report presents recommended improvements for the geometric design and safety performance of at-grade intersections on expressways. In general, the operational and safety performance of these multi-lane divided highways nearly matches those of rural interstates. However, because expressways allow for stop-controlled at-grade crossings, increases in both major and minor roadway traffic volume have had a significant impact on intersection safety in recent years. The study investigated alternate safety improvements and indentified their relative effectiveness and focused on reduci
This document became the first national guide focused specifically on driveway design since the publication of AASHTOs An Informational Guide for Preparing Private Driveway Regulations for Major Highways in 1959. Since 1959, the transportation system and its needs have changed drastically, and this report addresses the need for a comprehensive driveway design guide that accounts for vehicles, pedestrians, and bicyclists. The report identifies more than 90 design elements that directly or indirectly affect the geometric design of a driveway or access point.
Dixon, Karen (et al.) NCHRP 03-99: Development and Application of Access Management Guidelines, Transportation Research Board of the National Academies, Washington, D.C., Oregon State University (in progress 2011)
TRBs National Cooperative Highway Research Program (NCHRP) Report 672: Roundabouts: An Informational Guide Second Edition explores the planning, design, construction, maintenance, and operation of roundabouts. The report also addresses issues that may be useful in helping to explain the trade-offs associated with roundabouts.