There is an ongoing discussion among bicyclists who take notice of such things about whether it is better to construct roads with marked bike lanes, as is the practice in Gainesville, or with wide curb lanes (which can be found on some local streets, such as 34th St between Archer Road and NW 16th Ave.).
Peter Warwick compiled the following list of pros and cons of each position (as posted to the labmembers mail list on cycling.org).
Bikelanes
Pro:
* attracts more cyclists
* provides a place (separate space) on the road for cyclists
* provides a measure of safety for cyclists
* shows proper positioning for cyclists
Con:
* provides a false sense of security
* increase the danger for cyclists (at intersections and when cyclists must leave the lane for some reason)
* threatens cyclists right to use the roads
* increases the number of incompetent cyclists
* are not swept clean
* encourages improper positioning of cyclists
Shared Lanes
Pro:
* does not confuse cyclists or motorists
* does not discourage proper positioning for turns
* lanes are kept swept by the passing of motor vehicles
* does not require any special markings
Con:
* most cyclists don't feel secure in a shared lane
* does not delinate a place on the road for cyclists
* is dangerous for cyclists, especially on high volume, high speed roads
* problems with trucks, buses and bicycles sharing the same lane