What happens to crash severity when traffic volume increases?

• A. Decreases
• B. Increases
• C. Stays the same
• D. Varies by region

Answer: (A)

Crash severity is driven by the speed at impact and the energy involved in a crash. When traffic volume rises, speeds commonly drop due to congestion and tighter following distances. Since crash energy grows with the square of speed, even a modest decrease in speed can markedly reduce the potential for serious injuries. So, although more vehicles on the road can mean more crashes overall, the injuries in each crash are typically less severe at higher traffic volumes. This is why the general trend points to a decrease in crash severity with increased volume. There can be exceptions, but that’s the most consistent pattern.