“San Francisco’s Shared Lane Pavement Markings: Improving Bicycle Safety” is a study and report produced by Alta Planning + Design.
Figure 5 from the report shows that the shared lane markings induced bicyclists to ride 3 or 4 inches further from parked vehicles. However, this is not nearly far enough – bicyclists still operated well within the Door Zone.
Critique of “San Francisco’s Shared Lane Pavement Markings: Improving Bicycle Safety” shows that this study is not credible research and has numerous flaws and biases.
But based on this faulty study, the Bicycle Technical Committee and the other members of the National Committee on Uniform Traffic Control Devices specified an inadequate 11’ minimum placement when next to parking for the Shared Lane Marking in the 2009 Manual on Uniform Traffic Control Devices (MUTCD). Moreover, the lateral placement Guidance for roads without parking is also flawed.