I was just thinking the same thing, no physical barrier is just asking for an accident. I believe it to be foolish to allow bicycles on any public road with a speed limit over 20 mph. A quick search shows the average speed in a bike lane to be 12-16 mph. Evidently drifting outside your lane is so common that most states now have rumble strips on the outside of exterior lanes to let people know they’re drifting outside the roadway. We’ve got a lot of two lane blacktops in the rural area’s and it’s pretty common to come around a curve or over a hill and find a couple of folks riding bicycles in the road. Had a local female Doctor got killed a couple of years ago nth of town riding a back road. Had a young lady get killed last year riding in a service road by I-20.
That's a good point, but in my (professional) view it has nothing to do with the speed of traffic on the road. It has everything to do with the size and weight of a motorized vehicle compared to the bike, and the operating configuration where the cyclist has his back to the traffic in which he operates (as opposed to pedestrians, who have a clear view in both directions when crossing a street at a crosswalk).
In professional settings, I usually demonstrate the idiocy of these bike lanes by rattling off a list of all the protective measures that have been added to passenger vehicles over the years: seat belts, air bags, crash-protection technology, rollover protection, etc. Then I point out that the only "protective measures" the cyclist has in a bike lane on a public street are a helmet and a pavement marking. In my humble opinion, no responsible engineer should consider this an adequately safe roadway configuration under any circumstances.
Word.