The CDC says alcohol impairment is a factor in 31% of traffic fatalities. On Friday and Saturday nights (presumably peak impairment time), checkpoints determin

The CDC says alcohol impairment is a factor in 31% of traffic fatalities. On Friday and Saturday nights (presumably peak impairment time), checkpoints determine that about 3% of drivers are impaired. http://www.iihs.org/iihs/sr/statusreport/article/48/10/1 http://www.iihs.org/iihs/sr/statusreport/article/48/10/1