Designing Road Diet Evaluations: Lessons Learned from San Jose’s Lincoln Avenue Road Diet

This report analyzes traffic impacts from the 2015 implementation of a pilot “road diet” on Lincoln Avenue, in the City of San Jose, California, comparing data on traffic volumes and speeds from before and after the road diet was implemented. The analysis looks at impacts on both the road diet location itself and on surrounding streets likely to have been impacted by traffic diverted off the road diet segment. The results within the road diet zone were as expected, with falling volumes and numbers of speeders. The all-day data aggregated by street type (e.g., neighborhood streets, major streets) showed limited overall negative impacts outside the road diet segment. These summary results do not tell the entire story, however. Individual locations, particularly among the neighborhood streets, saw more noticeable negative impacts. The report ends with recommendations for best practices in designing and conducting road diet evaluation studies.

Key findings