Safety Surrogate Studies

A Safe System Approach is a proactive approach. Humans make mistakes and redundancy is key for no single mistake to lead to a serious injury or loss of life. Although crash analyses mean waiting 3 to 5 years for the appropriate sample size of data, the City can conduct before/after studies to determine the effectiveness and performance of new infrastructure in a much shorter timeframe. Crashes are one metric for evaluating success, but it is not the only way – there are several indicators of potentially severe crashes that the City can use to assess safety on the road network.

Safety surrogates, or factors that indicate the potential for a crash such as near misses, can be measured by observational studies, video analytics, and machine learning algorithms. These surrogates detect situations that could potentially lead to severe crashes, even if these situations did not result in a crash at the time. Analyzing safety surrogates can be used to examine crash contributing factors, such as speeding and red light running, and evaluate the efficacy of treatments that target and address these and other conflict points. These analyses provide important information to deploy the lessons from safety interventions throughout the entire City.

​