The high accident and rest rate would be costly. I buttume you are saying that more than economics must be considered which is certainly true.
Don't know if that is true are not. There are a lot of things positive and negative with bikes.
The accident rate goes at a exp(speed difference^2) as the slower vehicles such as bikes are hit when they are not keeping up with the flow of traffic. That is one reason that bikes are banned from freeways.
You are buttuming that there is not a cost to bikes riding in the same lanes with cars when the cars are going faster. That is deadly false. When bike keep up with traffic like in crowded downtown traffic, riding with the other traffic is common and seems to be safe.
A full lane for bikes could be 5 or 6 feet. It does not mean you are allowed to ride with fast cars especially on freeways.
BTW I don't and motorcycle cops don't ride totally within a lane in California (legal lane splitting). Does your interpretation mean that no one can change lanes because they will not be totally within a lane when they are changing lanes. Your interpretation does not seem to be workable.
