I heard somewhere that if you remove 20% of the vehicles in peak hour, you'd eradicate something like two thirds of all traffic jams. Roads have always been designed to serve demand, which is a problem when your demand looks like this during any given day:
There's been talks of introducing per-mile-driven taxes over here. The last time that was on the political table, it also included a 'peak-hour-tax'. I'm rooting for that idea to make its return.