The FHWA recently released a design guide for protected bike lanes. Streetsblog has an excellent write up on it. In a local nod, the cover photo of the guide is of the L Street protected bike lane (by WABA's own Alex Baca) and there are a few other photos of the M and L lanes as well. It also calls out DDOT for money saving techniques and introducing bike-sharing in 2008.
Municipalities often consider more affordable, temporary materials for their flexibility and ease of installation. Washington, DC, built two of its newer separated bike lanes along L and M Streets NW, using flexible delineator posts and reduced use of green paint in order to save money on implementation while addressing neighborhood concerns about design. The District’s Department of Transportation estimates that separated bike lane construction costs on L Street may have been reduced by upwards of 50% as a result.
It includes a definition of separated bike lanes and some reasons for installing them, as well as some compelling safety data.
The analysis conducted as part of the preparation of this guide studied data from 17 separated bike lane corridors in 8 States (refer to Appendix C). Based on this analysis, separated bike lanes were generally associated with a decrease in total crashes and an increase in total bicycle crashes, however, when accounting for changes in bicycle volumes on facilities that provided sufficient pre- and post-implementation bicycle volume data, the per capita crash rates for cyclists appeared to decrease in most facilities after separated bike lanes were installed. Additionally, the analysis found that increases in bicycle crashes after separated bike lanes were built were especially pronounced at intersections.
Then there's a lot of wonky discussion of design elements, maintenance issues and funding mechanisms - among other things. That the FHWA has come out with such a document is a very positive development.