Originally Posted by danielf

Well, for one, some of them require you to give way on every side street/lane, which you don't have to do when riding on the road. Some have very poor surfaces with tree roots bumping up the tarmac providing a bumpy ride. Some are raised and don't have (proper) dropped kerbs at intersections/driveways meaning you have to come to a stop every couple of yards. Some have bloody big trees in the middle. Then there's the ones that make you cross a busy road twice in the space of 100 yards as the path stops and then continues on the other side of the road.

The upshot is that while some cycle lanes/paths are fine, there are many that are thoroughly ill-conceived and/or maintained and are better described as obstacle courses than cycle paths. What looks perfectly fine from a distance may be a nightmare to actually ride. The latter will be particularly true for people on road bikes with very narrow tyres that tend to travel faster (i.e. the lycra lads)