题目选项分析

The use of radar detectors in commercial vehicles was banned because commercial truck and bus drivers were using these devices to drive faster than the posted speed limit without fear of arrest. Since drivers of noncommercial vehicles also use radar detectors and since speeding decreases safety for any vehicle, use of radar detectors should also be banned in noncommercial vehicles to increase safety.

Which of the following, if true, most strongly supports the argument above?

【选项】The ban on radar detectors in commercial vehicles has been effective in deterring them from speeding.