Analyzing crash data at Cape Cod’s highway interchanges 

Quantifying crash data at highway interchanges can be challenging. For example, geolocation data sometimes misplaces crashes that happened along local roadways proximate to the highway, identifying them as highway crashes and leading to miscalculations in crash data.   

A new study conducted by the Cape Cod Commission focuses on the entrance and exit ramp intersections of the region's highway system, seeking to identify the highest crash intersections to better prioritize improvements and enhance roadway safety.   

"We aimed to understand what's happening at these intersections and how to reduce risk where it's needed most," said Cape Cod Commission Senior Transportation Planner, David Nolan, during a recent presentation to the Cape Cod Joint Transportation Committee.  

Traditionally, the Commission's high-crash location reporting has not included these intersections, often overlooked in broader interchange analyses. This study shines a light on critical, previously under-examined locations.  

The study analyzed 32 intersections across 15 interchanges, including Route 28 in Falmouth and along Route 6, excluding interchanges near the Bourne and Sagamore bridges, as those are being extensively studied as part of the Canal Bridges Project.   

Commission staff evaluated 1,100 crash reports from the Massachusetts Department of Transportation (MassDOT) to confirm whether incidents occurred at the targeted intersections or elsewhere on the highway. All reports reviewed were for crashes involving a motor vehicle.  

Through a combination of traffic counts and crash analysis, the Commission identified several high-risk intersections, including Route 6 eastbound at Route 134 in Dennis and Route 28 southbound at Route 151 in Falmouth. The study examined intersections by total crash counts, crash rates, and the severity of crashes.  

Notably, Route 6 eastbound at Route 134 northbound had 44 reported crashes over five years. Route 6 eastbound at Station Avenue/Union Street had 38 reported crashes during that period, and there were 29 crashes at Route 28 southbound at Route 151 in Falmouth. Fatal crashes occurred at both the Route 134 and Route 151 interchanges.  

The Cape Cod Commission plans to prioritize Roadway Safety Audits at the most problematic intersections to help identify countermeasures to improve safety. The goal is to integrate these intersections into the Commission's top 50 crash location listing so they can be visible in regional safety planning.  

The final report will provides detailed charts and metrics for all 32 intersections studied. Nolan noted the importance of maintaining updated traffic data: "Consistent, current data allows us to make informed decisions and continue improving Cape Cod's transportation network."

Learn more and view the final report by visiting capecodcommission.org/our-work/transportation-safety.