Ingersoll Avenue was converted from a four lane road (two lanes each direction) to a three lane road (one lane each direction with a left turn lane down the middle) in the spring of 2010. Gary Fox, Des Moines' traffic engineer, gave an excellent presentation about the project at the Institute of Transportation Engineers' Midwestern District conference last week (Download
Ingersoll3-laneMWITEpresentationJune2010Fox). A picture of the "after" condition from Gary's presentation is on the left. You can see they added a bike lane in each direction in the converted space.
There was significant business opposition to the project even though it added about 50 parking stalls to the central business district corridor. The business owners were concerned about heavy congestion hurting their businesses. The project is still in the middle of a six month trial period (it could be converted back), but the concerns of congestion haven't materialized. Furthermore, bicycle traffic has improved and there appear to be less crashes (although it's early to get "after" condition data).
This project is a great example of a successful "complete streets" conversion project. If you're considering this type of conversion, I suggest you contact Gary at email@example.com. But you better hurry – he's retiring in about a year.