Major crossroads are designed to facilitate the conflicting movements of numerous vehicles in a manner that is both safe and efficient. Accesses located within the functional areas of major crossroads add complication to intersection activity due to additional conflicts arising from ingressing and egressing movements at the accesses. In this research, the impact of accesses on crashes within major crossroad functional areas was analyzed. Specifically, the effects of access spacing within functional areas and access setback from intersections were addressed. In order to conduct the analysis, the functional areas of 159 signalized major arterial crossroads across the state of Utah were examined. A database was built containing the frequency, type, and severity of functional area crashes as well as the intersection and roadway characteristics within the functional area. Statistical analyses were conducted to determine the influence of accesses in intersection functional areas on functional area crashes. The statistical analyses show that the existence of accesses within the functional areas was correlated with increased crashes and crash severity costs. In particular, an increase in commercial access density was associated with increases in crash totals, crash rates, and rear end crashes in intersection functional areas. The analyses also showed that study site intersections meeting Utah Department of Transportation (UDOT) corner clearance standards exhibited fewer right angle crashes and lower crash severity costs. Finally, intersections that prohibited all unsignalized access had lower crash totals, crash rates, right angle crash totals, and rear end crash totals than intersections that allowed some unsignalized access.



College and Department

Ira A. Fulton College of Engineering and Technology; Civil and Environmental Engineering



Date Submitted


Document Type





crashes, safety, functional area, access management, intersections, corner clearance, access density, conflict points, crash severity