I beg to differ on this point, I am of the opinion that its the gaps people leave (or lack of) that causes jams, as soon as the car in front touches their brakes, it sets off a chain reaction of people braking (even if they arent actually braking, just 'comfort touching' the pedal) that eventually leads to jams. That and sheer weight of traffic too.
Im not saying lets all speed, and I do recognise what you are saying though