Originally Posted by Brian Ratliff
I would like some real research into how to design roads to accept multimodal traffic (cars, bikes, peds). So far, most the efforts have been somewhat of a cross between "rule of thumb", guesswork/experience, and hit-and-miss. I say this because the most common complaint is "well cyclists have only themselves to blame for getting hit - the road just isn't built for bicycles, it is the realm of cars..." or something to that extent. So, why not start building roads to accept of all forms of transportation.
But some real money should go into this, starting at the university level and working its way up to implementation on the street. It is a real engineering problem, mixing cars and bikes, and cycling must, at some point, be depoliticized and get some real, ol' fashion, nuts and bolts research. We have too many amateur "experts", too many "general purpose" advocates, and way too little research and development going on.
Just to be clear, by "multimodal" you mean
trimodal (cars, bikes, peds) as opposed to bimodal (vehicular, peds), right?
It's not an engineering problem. It's a basic math problem. Assuming you want to provide continuous segregated routes, as much as possible, for each mode, it's the intersections that are the problem. The intersections are a problem for just a single mode problem. The engineering problem is that we're trying to do this on essentially a single plane. That means you have to stop certain flows across an intersection to allow another through (stop signs, traffic signals). The alternative is much more expensive; grade separation.
When you add a second mode to the problem, that complicates the problem. Others understand this, and so seek to eliminate cars, for example.
But adding a third mode, that's really impractical. You either have impractically expensive multi-grade solutions at intersections, or you have to allow mode-specific flows at intersections, adding delay for everyone. Again, this is already a problem in just a bimodal system (consider how many peds are killed per year).
Adding a third mode to bimodal transportation system complicates everything by probably an order of magnitude. That makes it impractical.