Presentation | 2017
Safety Analysis of Driveway Characteristics in South Carolina Using GIS
- Authored by: Wayne A. Sarasua, Ph.D.
- Event: 2016 International Conference S. Africa
The overall goal of this project is to enhance SCDOT’s current access management practices resulting in a reduction in crashes, injuries, and fatalities on South Carolina roadways as well as improved traffic flow.
Findings & Conclusions
- Problems result when developers circumvent standard adherence through the waiver process
- Comprehensive driveway database critical to analysis
- Precise crash data is critical to analysis
- Makes it possible to associate crashes with driveways
- Can also facilitate corridor level and even statewide analysis with more robust results
- Reading crash narratives is time consuming and it is sometimes difficult to associate a crash with a particular driveway
- Use junction type with caution. Many driveway related crashes may be overlooked.
Research Golden Nuggets for Practical Application
- Research Findings: Raised medians can cut driveway related crashes in half (CMF of 0.49).
- Right-in, right-out driveways eliminate 3 conflict points that are the most critical with respect to crash severity and RIRO driveways have less than half the crash frequency of full access driveways.
- Reducing access point density improves roadway capacity and reduces need for new capacity improvements.
- Driveways within 150’ of a an intersection have nearly twice the crash frequency of driveways 150’ to 300’ from an intersection.
- Better access policies result in lower crash severity, not just frequency.
- Approval of access waivers from adherence to good design practice often result in higher crash frequency.
- High turnover land use such as fast food restaurants have much higher crash frequency over other land uses such as small businesses.
Wayne A. Sarasua, Ph.D., P.E.
**Won an award from AASHTO High Value Research Project
YouTube video presentation will be linked at a later date.