For years I have been advocating more "road diets" in Missouri. Basically that means instead of automatically going to a 4-lane road when "improving" a two lane road, there is something in between--a 3 lane road with bike lanes.

The 3-lane gives the same travel time for motorists, can handle pretty much the same amount of traffic, has MUCH lower collision rates for motorists, is much friendlier for people (ie, pedestrians, bicyclists, disabled, etc.), discourages speeding, and has other benefits for a business area or neighborhood.

This study, from a traffic engineer in Iowa, bears this out and more.