How old do you think I am? What do you mean by keeping up with traffic? when I go uphill I do not ride as fast as cars by all means, that doesn't mean I can not use the road. If a faster driver comes behind me he either: 1. slows down and waits, 2. passes if it is safe to do it. The good thing about the road system is that it allows for vehicles of all types and speeds. Can't you drive your car in a road where there are ferraries and big trucks? Learning to ride well is easy, it doesn't requiere superhuman skills. Building separate infraestructure does not help to learn to ride, quite the opposite it encourages people to think that bicycle drivers are inferior and incapable of learning, it creates the Cyclist ghetto.