||Phase 2 Experiment: Reconsidering the Impact of Access Spacing on Crash Risk
John S. Miller
The spacing of access points is one of the most critical elements in access management. One of the long-held hypotheses is that a higher access density results in higher crash risk. The longer term goal of this research is to determine whether or not and in what manner access spacing affects safety. This study determines whether or not, or in what manner, access spacing—where access denotes a point at which vehicle traffic can enter or leave the roadway—affects safety. The findings may lead to recommended changes to the VDOT access spacing standards shown in Appendix F of the Road Design Guide. A work plan has been developed as Phase 1, and Phase 2 of this project develops a scientifically rigorous statistical model, and corresponding theory, to explain the effect of access spacing on crash risk after controlling for traffic exposure and other contributing factors.