Collisions between cars and bikes are almost twice (180%)as likely to occur when bike paths with two way traffic cross driveways and roads. At least one study made this clear conclusion. 

The reason is that motorists coming out of or in to their driveways either forget to stop and look for bikes, and if they do, they often fail to look both ways.

This study did not account for situations where visibility is reduced by brush. Nor does it account for many drivers being short term renters, not familiar with the territory. 
Edgartown Police records apparently clearly indicte that the present systems works because no auto bike collisions have been reported on Chappy whereas an unfortunate number have occurred at bike paths elsewhere in Edgartown.

One major cause of bike accidents not invoving cars is sand on the path. Unless the town sweeps the bike path after every rain storm or after multiple cars traveling on sandy roads cross the bike path, it will be inevitable that accidents will result, as sand accumulates.

It is a great falacy that bike paths are safer than biking on a road fed by a ferry system that, at most, with both ferries running, has one car per monute, plus whatever local traffic there might be on the island. Even one way bike paths on both sides of the road will, I believe, cause more accidents.

Posted by Lionel Spiro on Wednesday, 12/31/08 @ 4:20pm