A Crash Modification Factor that is less than 1.0 indicates what about crashes?

A Crash Modification Factor (CMF) that is less than 1.0 indicates a potential reduction in crashes associated with a certain intervention or condition. CMFs are used in traffic safety analysis to quantify the effectiveness of various treatments—such as new traffic signals, road designs, or enforcement strategies—in preventing crashes.

When the CMF is below 1.0, it suggests that the measure being evaluated has a beneficial impact, decreasing the frequency of crashes. For example, if a safety intervention is expected to reduce the number of crashes by, say, 20%, the CMF would be calculated as 0.80. This factor reflects not just a statistical measurement, but it serves as an essential tool for traffic engineers and policymakers to prioritize and justify safety improvements.

The other options present scenarios that do not accurately describe the implications of a CMF below 1.0. For instance, a CMF of 1.0 would indicate no change in crashes, while a CMF exceeding 1.0 suggests an increase in crashes. Hence, a CMF less than 1.0 is interpreted explicitly as a signal that the implementation in question is likely effective in reducing crashes.