Shortly after the new limit was posted, an MP sergeant issued a speeding citation（引用，传票） 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（慢跑） to get to the PX before it closed," he explained, "and as I passed the jeep, I noticed that the speedometer（速度计） read five m.p.h."