According to firm scientific evidence developed right here at the University of Utah talking or texting on a cellphone while operating a motor vehicle results in a level of driver impairment equal to that of those who drive while intoxicated. Thus the bill approved by the Utah House, prohibiting the use of cellphones by drivers under the age of 18, is the logical equivalent of banning drunk driving for teens, but not for adults.
The fact that lawmakers aren't willing to ban cellphone use by drivers of all ages suggests that they want to be seen as acting on a problem, but not acting so forcefully as to offend anyone who might vote against them in the next election.
The move is in a similar vein to a bill that was one of the worst ideas of the last legislative session, the one that basically would have removed meaningful sex education from Utah public schools. That bill, like the ban on cellphone use by drivers under 18, was designed to give some grown-ups the feeling of having accomplished something, but doing it in a way that had little political risk because those who would have been disadvantaged by the law were below voting age.