Zig Zag Road Striping Calms Traffic in Virginia

Virginia Department of Transportation installed these zig zag pavement markings to caution drivers about the potential for pedestrians and cyclists by a popular trail crossing. Photo: Virginia Department of Transportation
Virginia DOT installed these zig zag markings to caution drivers approaching the intersection of a popular walking and biking trail. Photo: Virginia DOT

At 11 points in northern Virginia, the familiar straight dashed lines on the road gives way to a series of zig zags. The unusual markings, the result of a pilot project from the Virginia Department of Transportation, are meant to alert drivers to be cautious where the Washington and Old Dominion (W&OD) Trail intersects with the road — and bicyclists and pedestrians frequently cross.

After a year-long study of this striping treatment, Virginia DOT officials say the markings are effective and should become part of the Manual on Uniform Traffic Control Devices — the playbook for American street designers.

This photo shows another style of zig zag pavement marking tested in Virginia. Photo: VDOT
This photo shows another style of zig zag pavement marking tested in Virginia. Photo: VDOT

VDOT found the zig zag markings slowed average vehicle speeds, increased motorist awareness of pedestrians and cyclists, and increased the likelihood that drivers would yield. They also noted that the effects of the design change didn’t wear off once motorists became used to the it — they still slowed down a year after installation.

VDOT says the results indicate that zig zag markings are a more cost-effective solution for conflict points between trails and high-speed roads than the current treatments: flashing beacons placed above the road or off to the side.

The zig zag concept was imported from Europe. It is currently used in only two other locations in North America: Hawaii and Ottawa, Ontario. It was one of more than a dozen European traffic management techniques VDOT zeroed in on to test locally.

The zig zag markings reduced motorist speeds approaching the trail at Belmont Ridge Road, according to a VDOT study. The effect was long lasting.
The zig zag markings reduced motorist speeds approaching the trail at Sterling Road by about 5 mph, according to VDOT. The effect remained strong over time.

The W&OD trail is a popular route for both recreation and commuting in the D.C. metro area. Between 2002 and 2008, there were 21 collisions involving cyclists and two involving pedestrians along the trail, which intersects with major roads at 70 points along its 45-mile path in Fairfax and Loudoun counties in Virginia.

The effect of the zig zag markings was measured using speed radars over the course of a year. Feedback from motorists, cyclists, and pedestrians was also collected using online surveys. While the survey did not come from a random sample, 65 percent of drivers said they were more aware because of the markings and 48 percent said they liked them. The zig zags were also popular with cyclists; 71 percent said the markings affected driver behavior.

Said one respondent: “Drivers rarely stopped before the markings were installed. Since installation, they stop much more often.”

  • High_n_Dry

    We are a wonderfully complex and simple species. Build a rocket to mars, no problem. Squiggly lines on pavement, too much stimuli – must. slow. down. Hopefully this idea will spread to other DOTs.

  • Bernard Finucane

    Those intersection photos are horrendous. Whoever designed and approved them don’t any respect for human life.

  • Peter T

    Correction: A third zig zag location is in Washington State.

    http://wsdotblog.blogspot.com/2015/08/new-zig-zag-pavement-markings.html

  • I worry about out of town drivers that have never seen such striping before. I had a discussion a few weeks ago with some angry Los Angeles bike rider over green lanes and pointed-out that only 8 or 9 cities even have green lanes, which means that the residents of the nation’s other 991 out of 1000 largest cities have no idea what a green lane even is. Just remember that the next time that a car violates your precious green lane.

  • wookie54444

    it is amazing how this supposedly new science has come to light just now LOL it has been used in England for nearly 40 years now at what they call zebra crossings the same as your crosswalk in the picture. i wonder where they got the idea from?

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