Green Pavement Markings at Bike Lane Weaving Area
St. Petersburg, Florida
Prepared by Kristen Langford, UNC Highway Safety Research Center
First Avenue N in St. Petersburg, Florida, is a one-way street with five travel lanes, including a left-turn-only lane, three through lanes, and a right-turn-only lane. There is a bike lane positioned between the right-turn-only lane and the next through lane. The bike lane continues for a number of blocks through this area. The City of St. Petersburg requested and was granted permission by the Federal Highway Administration to use green pavement and accompanying signing in the bike lane weaving area on 1st Avenue N as it approaches the intersection with 34th Street. A traffic count showed a total of 16,793 vehicles, including 2,902 right-turning vehicles, or 17 percent of the total. Video data collected before and after the installation of the treatment showed that 90 percent of bicyclists traveled straight through the intersection.
The green pavement marking in St. Petersburg.
Photo by the UNC Highway Safety Research Center.
The treatment was installed in two phases. The first phase, which began in March 2007, involved painting the 190-foot dashed striping area green and installing new signage at the start of the green bike lane weaving area. The city also issued a press release and used a variable message board with the following message to motorists: RIGHT TURN YIELD TO BIKES. After several months with the paint and signs in place, it was felt that some motorists did not understand the intent of the green paintthey were either crossing behind or in front of the green weaving area. Phase 2 of the treatment began in August 2007 when the city decided to install black mini-stripes in between the white dashed striping area. This enhancement was accompanied by a new press release and new variable message board message: YIELD TO BIKES AND CROSS IN GREEN.
Evaluation and Results
Hunter, Srinivasan, and Martell (2008) completed an evaluation study for the Florida Department of Transportation. Video data of the "before" period were collected in February, May, and September/October of 2006. The "after" video data were collected in May 2007 for Phase 1 and in October 2007 for Phase 2. For the before and after periods, the researchers coded a number of attributes and measures of effectiveness, including:
- Bicyclist characteristics and behaviors
- Yielding behavior
- Avoidance maneuvers and conflicts
- Bicycle and motor vehicle responses while interacting
- Use of green bike lane weaving area by motorists
- Motorist signal for right turn
- Bicycle head scan
A significantly higher percentage of motorists yielded to bicycles in the after period (86.7 percent before; 98.5 percent after). The percentage of motorists that signaled their intention to turn right increased significantly from the before to the after period (85.2 percent of motorists signaled before; 89.2 percent signaled after). A significantly higher percentage of bicycle riders scanned for proximate vehicles in the after period (6 percent scanned before; 12 percent scanned after). While the percentage of conflicts (sudden changes in speed or direction) was lower in the after period, the number of conflicts was too small to test for statistical significance. It is important to note that most of the conflicts in the after period were between motorists who were maneuvering near the bicyclists. For many of the interactions and maneuvers that were observed, there was very little difference between Phase 1 and Phase 2.
Conclusions and Recommendations
The green bike lane weaving area led to operational benefits for bicyclists on this busy, multilane roadway with a high proportion of motor vehicle right turns. The significant increase in yielding behavior by motor vehicles is an important finding and matches what was found in the earlier evaluation of the blue bike lane weaving areas in Portland, Oregon. The increase in the number of motorists signaling their intent to move to the right-turn lane is also a safety benefit for the treatment in St. Petersburg.
Note: In 2012, the Florida Department of Transportation issued Roadway Design Bulletin with further detail on colored bicycle lane design. Available at: http://www.dot.state.fl.us/rddesign/Bulletin/RDB12-01.pdf
St. Petersburg, FL 33712
Hunter, W. W., R. Srinivasan, and C. A. Martell. Evaluation of a Green Bike Lane Weaving Area in St. Petersburg, Florida. Final Report to Florida Department of Transportation. 2008.