A city aims to encourage bicycling (and thus improve public health) by converting a lane on a crowded thoroughfare into a bicycle lane. The new design will slow traffic initially, but because the lane is safer the city hopes that more car drivers will switch to bicycling. In the longer term, the city envisions that the street’s traffic will flow more smoothly when a portion of car traffic is reduced.
In assessing the plan’s chances of accomplishing its goal, it would be most helpful to know which of the following?