FHWA has published a TechBrief, summarizing a study whose purpose was to evaluate the impact of several uses of shared-lane pavement markings – specifically the “sharrow” design – on operational and safety measures for bicyclists and motorists.  Experiments were conducted in Cambridge, MA; Chapel Hill, NC; and Seattle, WA.  The study concludes that, “sharrows can be used in a variety of situations, and increased use should enhance motorist awareness of bicyclists or the possibility of bicyclists in the traffic stream. Results indicate that sharrows increased operating space for bicyclists.  Sharrows have reduced sidewalk riding not only in the current study but also in a previous study in Gainesville, FL.”