Operational Analysis of Shared Lane Markings and Green Bike Lanes on Roadways with Speeds Greater Than 35 MPH.

摘要

This study analyzed the effectiveness of shared lane markings (sharrows), wide curb lanes, standard and buffered bike lanes, and green bike lanes on improving operations of bicycle facilities. Three measures of effectiveness were used in this study: lateral separation between the motor vehicle and bicyclist, the distance of bicyclists to the curb or edge of pavement, and the yielding behavior of drivers and cyclists at merge points. Also, motor vehicle speeds before, while, and after passing bicyclists were analyzed. Except for the Bridge of Lions site, the before-and-after data indicate that installation of sharrows led to an increase in lateral separation between motor vehicles and bicyclists. At Riverside Drive, the separation increased by 0.67 feet, while at the North 56th Street site, an increase of 2.55 feet was observed after installing sharrows and increasing the outside lane width. Data also suggested a significant improvement in lateral separation of 0.86 feet at Sunset Drive, which was widened to create a wider outside lane (but had no shared lane markings), and Bailey Road, where a marked buffer between the travel lane and bike lane resulted in an increase in separation between motor vehicles and bicyclists of 0.72 feet. It was also observed that bicyclists rode further from the curb/edge of pavement for the after-period compared to the before-period for Riverside Drive, Bridge of Lions, North 56th Street, and Sunset Drive. P-values less than 0.05 were observed for these five sites suggesting that the treatments were effective in moving bicyclists further from the curb/edge of pavement. Data also indicates that drivers slow down as they pass bicyclists on non-limited access roadways (before speed of 32.02 mph to 29.97 mph while-passing) and then increase their speeds after overtaking the bicyclists (30.80 mph while-passing to 32.82 mph after-passing). The difference between the speeds before-passing and while-passing, and while-passing and after-passing, were both significant with a p-value less than 0.000. However, when the before-passing (32.02 mph) and after-passing (32.54 mph), excluding while-passing speeds, were analyzed, no significant difference was found (p-value = 0.110). For limited access facilities, the difference between the overtaking drivers speed before-passing (37.35 mph) and while-passing (34.93 mph) the bicyclists was significant with a p-value of 0.000. However, the difference between motor vehicle speeds while-passing bicyclists (34.94 mph) and after-passing (35.48 mph) was not significant (p-value = 0.150). Contrary to the non-limited access streets, the difference between vehicle speeds before- (37.33 mph) and after-passing (35.48 mph) was significant for the limited access facilities (p-value =0.017).