Changes in the total number of people speeding and the overall operating speed provide information about the typical or median experience on the street or corridor. This metric is important to capture because it is the simplest. However, unlike high-end speeding, the number and percent of drivers exceeding the speed limit definitionally changes as the speed limit is reduced, so policy makers should be careful when using this metric to explain the impact of a project.
When necessary, the speed of the median or 50th percentile driver can be used to understand the typical experience on a street. Assuming traffic along the corridor is distributed normally, the majority of drivers will cluster around the median. A large difference between the median and 95th-percentile speed can indicate a high prevalence of high-end speeders or that there are too many opportunities to speed.