Zig-Zag Pavement Markings are Effective

Those unusual but eye-catching pavement markings installed on two roads that intersect with the W&OD Trail in Loudoun County are helping to slow motorists and bicyclists, that according to an experiment conducted by the Virginia Department of Transportation (VDOT) and its research arm, the Virginia Center for Transportation Innovation and Research (VCTIR).

Zig-zag pavement markings were installed on Belmont Ridge Road and Sterling Boulevard in 2009 to test their effectiveness in improving safety at trail crossings. The 45-mile W&OD trail has more than 70 highway crossings through Arlington, Fairfax and Loudoun counties, creating the potential for serious crashes between vehicles and bicyclists and pedestrians.

“Before the study, we thought the zig-zag pavement markings would have an immediate impact on motorist awareness, but over time would lessen,” said Lance E. Dougald, Research Scientist at VCTIR. “It was interesting to see that the markings actually had a sustained positive impact on speed reduction even after the markings had been in place for one year. One possible explanation for this is that markings installed within the roadway, especially unique markings, are more visible than signage and are less likely to blend into the roadside environment.”

The one-year study found that the markings installed in advance of the two crossings heightened the awareness of approaching motorists. This was evidenced by reduced mean vehicle speeds within the marking zones. Further, a majority of survey respondents indicated an increase in awareness, a change in driving behavior, and a higher tendency to yield than before.

Motorist awareness was assessed by before and after speed studies. Motorist attitudinal changes were assessed through a survey targeting motorists, pedestrians, and cyclists familiar with the markings. The survey was distributed via links posted on the Loudoun County government office website and electronic newsletters distributed by the Broad Run and Sterling District supervisors’ offices. Links were also distributed to bicycle clubs operating throughout the northern Virginia area. Motorist understanding was assessed through a hand-out survey in a different region of the state that targeted motorists unfamiliar with the zig-zag markings in Loudoun County.

The study recommends that VDOT continue to re-mark and maintain the zig-zag pavement markings at both test locations and monitor and collect data on crashes at both locations for three years.

The zig-zag pavement markings are a low-cost alternative to other safety improvements at mid-block locations. The pavement markings come in two different styles, and were approved for this test by the Federal Highway Administration after seeing the successful use of these markings in the United Kingdom and Australia.

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