I learned about "road diets" reading our local transpo plan. One tidbit was that a typical, modern 4-lane undivided street has 15-foot wide lanes and no bicycle provision. One possible "road diet" solution is to restripe the road with a center "left-turn only" lane, one lane each way for through motor traffic, and then the outside lanes for bicycle traffic. Contrary to perception, this arrangement was shown to improve motor traffic flow, since it reduced the necessity of waiting behind left-turning traffic.

Another idea is simply to restripe to 12 or even 10 foot lane widths, adding room on the edges for bikes. The narrower lanes have a calming effect on the traffic, too.

This kind of paint-engineering is a lot more affordable than building seperate bike infrastructure. Estimates from the same transpo plan place restriping a 4 mile stretch near me at about $60-70,000, but building a separated "bikeway" (MUP) at closer to $2 million. Still, I predict the MUP will be built, because it follows what the city has done elsewhere, and because the cost of it can be levied on future developers of the affected land. (Local provision is that "new developments" will incorporate bicycle and pedestrian infrastructure.)