Roadway Departure
Introduction
Roadway Departure has been a factor in at least 63% of reported fatal crashes in Tribal areas. A roadway departure crash occurs when a vehicle leaves the traveled way resulting in a crash and may start with any of these events: impact with guardrail, impact with a fixed object (tree, utility pole, boulder, building, ditch, fence, etc.), ran off roadway, crossed median, crossed centerline, airborne vehicle, or re-entering the roadway.
Most roadway departure fatalities (71%) involve only o ne vehicle. Nine in ten roadway departure fatalities occur in rural areas with a significant portion, 47%, occurring on minor collector or lower classification rural roadways. Traffic volumes are typically lower at night, yet 43% of roadway departure crashes occur in the dark and 6% during dusk or dawn. Weather does not seem to play a significant role. (Source: Tribal Transportation Strategic Safety Plan)
Video
Training
There is a “Systemic Roadway Departure Countermeasures” category in the Tribal Transportation Program Safety Fund. This category has a goal of dedicating 25% of the available TTP Safety Fund toward addressing roadway departure. This category was established to streamline access to low-cost roadway departure countermeasures because roadway departure is involved in 63% of fatal crashes in Tribal areas.
Below is a link to the form that Tribes can use to request improvements aimed at reducing rural roadway departure during active TTPSF funding cycles. Tribes could also request funding from the “Data Assessment, Improvement, and Analysis” category to conduct a systemic safety study to collect the necessary data for participation in this new category.
TTPSF Systemic Roadway Departure Countermeasures Risk Assessment Form
Retroreflectivity
About half of all roadway departure crashes in Tribal areas occur during low-light or night conditions. Ensuring the visibility of signs and pavement markings at night is one important way to reduce roadway departure crashes. Establishing pavement marking and sign maintenance policies is one way to address this need. Below you can find links to resources including the applicable sections of the MUTCD and case studies.
- Know Your Retro Fact Sheet
- FHWA Night Time Visibility for Signs
- FHWA Night Time Visibility for Pavement Markings
- Summary of Sign Maintenance Methods
- TRB Synthesis Report: Practices to Maintain Traffic Sign Retroreflectivity
- MUTCD: Sign Retroreflectivity (2A.08), Sign Conspicuity (2A.15), and Pavement Marking Standards (3A.02.03)
- Case Study: Umatilla Sign Retroreflectivity
- Case Study: Sisseton Wahpeton Oyate Signs Retroreflectivity
- Case Study: Seminole Tribe of Florida Retroreflectivity Pilot Program
Resources
FHWA Focus on Reducing Rural Roadway Departure (FoRRRwD)Visit Web Page
Fatal Rollover Crashes in the Navajo AreaDownload
Factors Related to Fatal Single-Vehicle Run-Off-Road CrashesDownload
FHWA Video: Curve Signing: Proper Chevron SpacingWatch
- An Introduction to Curve Warning Signs: Curve Warning Signs Save Lives (storyboard)
- Rumble Strips: The Sweet Sound of Safety (video)
- NCHRP Report 500: A Guide for Reducing Collisions on Horizontal Curves
- NCHRP Report 500: A Guide for Addressing Run-Off-Road Collisions
- NCHRP Report 500: A Guide for Addressing Collisions with Trees in Hazardous Locations
- NCHRP Report 500: A Guide for Reducing Collisions Involving Utility Poles
- NCHRP Report 500: A Guide for Addressing Head-On Collisions
- NCHRP Report 500: A Guide for Reducing Head-on Crashes on Freeways
- FHWA Roadway Departure Safety: A Manual for Local Rural Road Owners
- FHWA Roadway Departure
- FHWA Proven Safety Countermeasures: Safety Edge, Horizontal Curve Enhancement, Rumble Strips, and more
- FHWA Low Cost Treatments for Horizontal Curve Safety
- AASHTO Roadside Design Guide
- FHWA MIRE 2.0 Roadside Rating
- MUTCD: Curve Warning Signs (2C.06)