Presentation | 2017

Safety Analysis of Driveway Characteristics in South Carolina Using GIS

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.

Driveways, Effects
Effects, driveway