We don't need them.
A better question might be, "
Why do we have them?"
We have them in large part for the same reasoning that there are some states where it is illegal to talk on a cell phone while fueling, because it
might cause an explosion, despite the fact that it has never happened, not even once, that a cell phone caused an explosion. But it seems to make sense, right? A sensible precaution and all that.
On the surface, it makes sense to segregate bicycles from motor traffic, because you'd think it would be safer. Turns out it's not. Segregated bike paths/lanes actually increase accidents except in certain very narrow circumstances. Even cycling groups who have commissioned studies to obtain foundational arguments for more bike paths have been burned by the surprising results.
Montreal is about the only city that has released a study showing an increase in safety because of bike paths, but their study was flawed because they compared relatively comparable parallel roads rather than before-and-after same roads with bike lane construction. In The Netherlands and Denmark, which have the highest rates of cycle usage combined with the best published records for safety (it's amazing how you can manipulate statistics), concludes that their bike path construction resulted in an increase in cycle traffic of 18-20% and a decline in car traffic of 9-10%, contributing to an increase in cycle usage along those routes. However, on those same reconstructed routes accidents and injuries
increased by 9-10%. Accidents mid-block decreased considerably, while accidents and injuries increased considerably at intersections.
They stated that in reality the accident rate is lower (even though their own statistics prove otherwise), because as bicycle riders increase, the
"likelihood an individual bicyclist will experience an accident goes down as the number of bicycle riders go up." Well, duh, Sherlock.
Wherever they have them, bike lanes at roundabouts are particularly dangerous, resulting in far higher accident rates than bike-pedestrian accidents on sidewalks (which is far higher than in-traffic, on-road accident rates).
Just like Amish buggy accidents, motor vehicle-bike accidents are highest on rural roads and lowest in city traffic, except for intersections, where bike accidents are the most frequent.
Bike paths aren't political, but it's a "makes sense, feels-good" liberal thing if there ever was one. Sounds good, looks good, but doesn't work. That's about as liberal as it gets. Just look at where the bike paths are the most popular.
There are a few bike paths that really and truly are safer. These are the ones that are physically separated from motor traffic, either by a wide median or a physical barrier. Also there are Bike paths that follow independent rights-of-way, which are roads specifically built exclusively for bicyclists (or, mostly in Europe, minor rural roads whose use is otherwise restricted to local motor traffic and agricultural machinery). Extensive interurban exclusive bike path networks can be found in countries such as Denmark, which has had a national system of cycle routes since 1993. Many of these make use of abandoned railway routes. Others, like the
Louisville Loop around Louisville, the 110 mile pedestrian and bike path that will eventually encircle the city in a
"City of Parks" are constructed specifically for bikes.
