Project description

Past research has shown, including studies by UC Berkeley’s SafeTREC, that crashes in congested conditions differ fundamentally from those in free-flowing traffic. Despite this, traditional traffic crash monitoring programs often overlook congestion as a factor when identifying high-risk locations. Recently, state Departments of Transportation have begun focusing on the most serious crashes (Fatal and Serious Injuries), which tend to occur in free-flow conditions. While this is a better approach to identify high-risk locations, there is room for further improvement by understanding the role played by congestion. During the recovery from the COVID-19 pandemic, traffic crashes in California have returned to prepandemic levels. Fortunately, fatal and serious crashes have not increased significantly, as seen nationwide (1). A common explanation for this trend is the increase in reckless driving, which tends to occur in free-flow conditions. However, it is very likely that the reduced congestion during the COVID recovery has heightened the risk of serious injuries on previously congested roads. This research aims to explore the extent to which these trends are driven by reduced congestion, providing a clearer picture of the factors contributing to high-risk road segments.