Generally, how is traffic volume related to crashes?

• A. As volume increases, crash frequency decreases and crash severity increases
• B. As volume increases, crash frequency increases and crash severity decreases
• C. There is no relationship between volume and crashes
• D. Crashes drive volume changes rather than the other way around

Answer: (B)

When you think about traffic safety, exposure matters: more vehicles on the road mean more opportunities for conflicts, so crash frequency tends to rise as volume increases. At the same time, higher volumes usually mean slower speeds because drivers slow down in dense traffic, and lower speeds reduce the energy in a crash. That combination leads to more crashes overall, but those crashes are often less severe than crashes that occur at higher speeds in low-volume conditions. So the best description is that increasing volume leads to more crashes, but with lower crash severity on average.

The other statements don’t fit because there is a clear relationship between volume and crashes, crashes don’t generally drive volume changes as the primary direction of influence, and it’s not true that crash frequency would decrease with higher volume or that severity would increase with volume.