In the UK, 90% of the cyclists are older men in the latest lycra racing gear on //edit//road bikes. In Brugges, people just get on a regular bike with a basket on the front wearing their normal clothes.
(Don't confuse "track bikes" and "road bikes"...)
The important difference is that track bikes do not have brakes. Most bikes on the road do.
*Yes - there are people cycling on the road using bikes without brakes. However, that's not 90% - it's a small minority. Cycling on the road in the UK without two braking systems (e.g. front brake, rear brake) is illegal, and unusual. Regardless, anyone cycling without a front brake is an idiot.