Understanding Collision Rate (CR)

The Collision Rate (CR) is a metric used to determine how often crashes occur at specific intersections or road segments. It is expressed as the number of crashes per million vehicles and helps identify high-risk areas for road safety improvements.

Collision Rate (CR) is a specific version used in traffic engineering to measure the frequency of crashes at intersections or road segments. It is expressed as crashes per million vehicles and is commonly used to identify high-risk locations and monitor changes in crash frequency over time.

Parameters Used

• CR: Collision Rate (per million vehicles) – The calculated frequency of crashes per million vehicles passing through a specific location.
• A: Number of crashes – Total number of recorded traffic collisions during the analysis period.
• V: Annual Average Daily Traffic (AADT) – The average number of vehicles passing a specific location per day over a year.
• D: Number of days in the analysis period – The total number of days over which the crash data is collected.
• T: Time in years – The duration (in years) for which the crash data is analyzed.

Purpose of Collision Rate:

• Identify High-Risk Areas: Pinpoint intersections or road segments with a high frequency of crashes.
• Monitor Trends: Track changes in crash frequency over time to evaluate the effectiveness of safety measures.
• Prioritize Improvements: Allocate resources to areas with the highest collision rates to improve road safety.

Practical Insights:

• Safety Measures: High CR values may indicate the need for traffic signals, speed limits, or road redesign.
• Data-Driven Decisions: Use CR calculations to support evidence-based road safety policies.
• Public Awareness: Share CR data with the public to encourage safer driving behaviors.