Using CMF Clearinghouse

Let’s consider a scenario with multiple countermeasures at a high-crash intersection. Suppose we plan to add both a left-turn lane and improve lighting to reduce crashes. We look up the CMFs on the CMF Clearinghouse:

  • CMF for Left-Turn Lane: 0.75 (25% reduction for left-turn crashes)
  • CMF for Improved Lighting: 0.8 (20% reduction for night-time crashes)

If we currently have 100 crashes per year at this intersection, applying both CMFs together:

Total CMF = CMFLeft-Turn x CMFLighting = 0.75 x 0.8 = 0.6
Predicted Crashes = 100 x 0.6 = 60

This high-level analysis suggests we could reduce crashes from 100 to 60 per year, a 40% reduction with both measures.