If you add so many buses that there's no congestion at all during the worst rush hour, you'll have enormous extra capacity just uselessly sitting around the res

If you add so many buses that there's no congestion at all during the worst rush hour, you'll have enormous extra capacity just uselessly sitting around the rest of the day. Obviously you'd want both: charge for congestion, and use the price signals you get to help you decide where (and when) to add capacity. Resources are limited, and buying yet another bus and hiring an extra bus driver just to shave the last tiny bit of congestion off Monday morning might be a noble ideal, but you might be better off using those funds to pay for another free school meal (or whatever other do-goodery is the best use of the marginal dollar).