Synthesis of Information Related to Highway Practices. Topic 48-01. Practices for Preventing Roadway Departure Crashes

A roadway departure (RwD) crash is defined by the Federal Highway Administration (FHWA) as “A crash in which a vehicle crosses an edge line, a centerline, or otherwise leaves the traveled way.” These crashes, comprised of run-off-road (ROR) and cross median/cross center line head-on collisions, tend to be more severe than other crash types. The reasons for ROR events are varied and include inattentive driving due to distraction, fatigue, sleep, or drugs; the effect of weather on pavement conditions; and traveling too fast through a curve or down a grade. There are also a number of roadway design factors that can increase the probability that a driver error will become a ROR crash (e.g., substandard curves, and unforgiving roadsides). RwD is one of the most severe types of crashes. According to a query of seven years of crash data (2007-2013) from the Fatality Analysis Reporting System (FARS) database, an average of 57 percent of motor vehicle traffic fatalities occurred each year due to RwD in the United States, necessitating further investigations. Over the past few decades, different engineering countermeasures have been proposed, implemented, and tested by various state and local agencies to mitigate RwD crashes. These countermeasures can be divided into three major categories: (1) signs (e.g., chevrons; dynamic curve warning systems; and advance curve warning and advisory speed sign); (2) pavement safety (e.g., high friction surface treatments; raised pavement markers; edge line pavement markings; safety edge; centerline rumble strips; and shoulder rumble strips); and (3) roadside design (e.g., cable barrier; guardrail; breakaway supports for signs and lighting; clear zone improvements; and shoulder widening). According to the FARS database, more than a quarter of all fatal crashes occur at curves, and 83 percent of those crashes are roadway departures. Enhancing curve delineation with signs is typically considered to be a low-cost safety improvement. Pavement safety countermeasures can also make significant contributions to reducing the number of RwD crashes. Collision with a fixed object has been identified as the primary harmful event in ROR crashes. Some practical countermeasures to enhance roadside safety include roadway cross-section improvements, hazard removal or modification, and delineation. These countermeasures have been used in all area types (i.e., rural, suburban, and urban) to keep vehicles in travel lanes and to reduce potential collisions with roadside objects, such as trees, signs, and utility poles. The objective of this synthesis is to document and summarize strategies and countermeasures taken by transportation agencies throughout the nation to prevent RwD crashes and the impact of those measures. The study will document strategies reported as effective as well as promising experimental technologies and strategies. Information will be gathered by literature review, a survey of state departments of transportation (DOTs), and follow-up interviews with selected agencies.

Language

  • English

Project

  • Status: Proposed
  • Funding: $45000
  • Contract Numbers:

    Project 20-05, Topic 48-01

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Gause, Jo

  • Start Date: 20160509
  • Expected Completion Date: 0
  • Actual Completion Date: 0
  • Source Data: RiP Project 40811

Subject/Index Terms

Filing Info

  • Accession Number: 01598966
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic 48-01
  • Files: TRB, RiP
  • Created Date: May 11 2016 1:00AM