The British RAF base where I was stationed as part of a contingent of USAF personnel had one narrow road winding through the crowded residential area. After a rash of minor vehicle-pedestrian accidents, the USAF commander decided to reduce the speed limit to three m.p.h.
Shortly after the new limit was posted, an MP sergeant issued a speeding citation to a jeep driver for going five m.p.h. I was curious to know how the MP had determined the jeep's speed so exactly. "I was jogging to get to the PX before it closed," he explained, "and as I passed the jeep, I noticed that the speedometer read five m.p.h."