Carol Martell

Evaluation of Shared Lane Markings in Cambridge, Massachusetts

Shared lane markings (sharrows) convey the message that motorists and cyclists must share the travel way on which they are operating. The purpose of the markings is to create improved conditions for bicycling by clarifying where cyclists are expected to ride and reminding motorists to expect cyclists on the road. A before–after evaluation was conducted to compare how cyclists and motorists operated on a street with parallel parking in Cambridge, Massachusetts, with no markings versus with sharrows placed 10 ft (3.05 m) from the curb. This evaluation, which was part of a broader FHWA study on sharrows, was intended to help determine whether an alternative to the 11-ft (3.4-m) spacing recommended in the 2009 version of the Manual on Uniform Traffic Control Devices would be effective. Operational and safety measures for bicyclists and motorists were examined. Overall, safety effects appeared to be associated with the installation of the sharrows placed 10 ft (3.05 m) from the curb. Perhaps the most important effect was the 14-in. (36-cm) increase in spacing between motor vehicles in the travel lane and parked motor vehicles when no bicycles were present. This effect increased the operating space for bicyclists. Many variables related to the interaction of bicycles and motor vehicles also showed positive operational and safety effects.

Evaluation of Rectangular Rapid Flash Beacon at Pinellas Trail Crossing in Saint Petersburg, Florida

The performance of a pedestrian safety device, the rectangular rapid flash beacon (RRFB), was evaluated at a street crossing of Floridas Pinellas Trail, a shared-use path where the majority of trail users were bicyclists. An elevated video camera beside the trail and several hundred feet from the crossing was used to collect before-and-after data for more than 1,000 bicyclists and pedestrians. The delay before trail users began to cross was reduced after the RRFB was installed. Bicyclists and pedestrians yielded considerably less, and motorists considerably more, after the installation. Yielding by motorists increased from 2% before to 35% after installation of the RRFB. When the flasher was activated, motorist yielding was 54%. In the before period, 82% of trail users were able to cross the intersection, whereas 18% were trapped in the middle. In the after period, these values were 94% and 6%, respectively. Installation of the RRFB increased the safety of trail users at the crossing. However, the device is not fail-safe, and communities that use it at trail crossings should be aware of this limitation. Education could help increase the percentage of trail users who push the button to activate the RRFB and increase motorist knowledge about the requirement to yield to pedestrians at crossings. Periodic police enforcement or the development of a passive detection system could also be helpful.