When a threshold concentration is used as the basis for pollution control, as it is for air pollution, one possibility for meeting the threshold at minimum cost is to spread the emissions out over time. To achieve this, one might establish a peak-hour pricing system that charges more for emissions during peak periods.

a. Would this represent a movement toward efficiency? Why or why not?

b. What effects should this policy have on mass-transit usage, gasoline sales, downtown shopping, and travel patterns?