That was a nice article on the fallacy of wide lanes. Unfortunately, it didn't deal much with the impact of dropping lane widths to ten feet for cyclists other than the one example where there were so many lanes on the roadway that dropping them from twelve to ten feet created the space for protected bike lanes on each side of the road.

Where most of us are riding, the roads aren't nine lanes across. However, I feel that ten foot lanes do increase our safety on the typical two to six lane roads I (we?) ride on. In a twelve foot lane, there is some question as to whether or not a cyclist should take the lane; some will and most won't. If a car is eight feet wide and a cyclist is two feet wide, then a cyclist can gutter hug and still have a two-foot buffer between the cyclist and the passing car. This can be even greater if the car slightly crosses the center and the cyclist overhangs the gutter a bit. Of course, some motor vehicles are wider than eight feet, some motorists won't move all the way to the left side of the lane to pass and debris/storm grates/road imperfections can keep the cyclist from being all the way into the gutter. Even still, most of the time gutter-hugging is just fine in twelve foot lanes, but most of the time isn't good enough for me.

What happens in a ten foot lane is completely different. There's just no way for a motorist to pass a cyclist while staying in the lane. Even if the cyclist is all the way to the right, the motorist is going to have to at least partially change lanes. Thus, many more cyclists will safely take the lane in ten foot lanes and experience fewer close passes. Personally, I like wide lanes, like thirteen to fourteen feet, that I can FRAP and I like ten foot lanes that I can simply take, but those intermediate widths are unsettling.