Because it changes the right of way and so you have to stop start more than you would otherwise. This has been done in places in Cambridge UK (a reasonably bic

Because it changes the right of way and so you have to stop start more than you would otherwise. This has been done in places in Cambridge UK (a reasonably bicycle friendly city). If your cycle lane is part of the road you can act like a car does - you get to ignore turnings because anyone joining the road has to give way as per normal. If you're on the pavement though, you're like a pedestrian - every turn off is a road you have to cross. Even if there isn't any traffic you have to slow down enough to look and as a cyclist what you want is constant speed. If you can't quite see what I'm talking about aee this example from Milton Road: http://www.rtaylor.co.uk/images/milton-road-1.jpg http://www.rtaylor.co.uk/images/milton-road-1.jpg The 'main' road is the one going into and out of the picture with cars on, and the image pictures a junction. You can see where the cycle lane 'crosses' the joining road and how you'd have to look for traffic (even ignoring the bump down and up that messes with a nice cadence). (from this blog post I found via Google: http://www.rtaylor.co.uk/anti-social-cycling-north-cambridge.html http://www.rtaylor.co.uk/anti-social-cycling-north-cambridge...).