VDOT envisions better street lights

Virginia transportation planners are embracing street light designs that produce less glare for motorists and decrease skyward light that washes out stars.

For the Virginia Department of Transportation, such a commitment comes two years ahead of a General Assembly-mandated deadline of July 1, 2004 that requires the agency only purchase shielded light fixtures.

Arlington Sen. Mary Margaret Whipple, D-31st District, sponsored the 2002 legislation that immediately affected other state agency procurements but gave VDOT time to study design approaches.

To that end, VDOT’s citizen-industry advisory committee on the issue met in Richmond for the first time July 16 and citizen members learned the agency is already installing fully shielded lights on local roads and semi-shielded lights on highway projects that are still in the planning stages.

“We really are very excited and thrilled that VDOT appears to be taking a very responsible approach,” said John Nusbaum, a member of the Virginia Outdoor Lighting Taskforce, or VOLT, who sits on the committee. “They’re moving in the same direction that everyone else is now.”

For three years, the citizens group VOLT has pushed for “dark sky-friendly” light fixtures, which are shielded on top so that light is directed downward, improving driver safety with less glare. The shielding also limits light pollution, which goes into the night sky and reflects off the atmosphere, reducing visibility of the stars and planets.

“What you see here in Northern Virginia are basically floodlights on the highways,” Nusbaum said. The lights on Interstate 95 angled at 45 degrees just shoot light across the highway, he said. “Glarebombs” is how his VOLT counterpart Bob Parks referred to them in an e-mail on the meeting.

“[Those lights are] the main reason that VOLT and the community was unhappy with the lighting that VDOT had done,” Nusbaum said.

Attendees of the VDOT lighting advisory meeting included experts from the International Dark Sky Association, National Electrical Manufacturers Association members Hubbell Lighting and GE Lighting, the Federal Highway Administration and VDOT’s engineering section.

The problem facing the advisory committee is that highways are too large an area to be lit with fully cutoff light fixtures, said VDOT traffic engineer Ilona Kastenhofer, who is heading up the advisory committee meetings.

She said, and Nusbaum agreed, that such a requirement would result in light that is too focused and reflects into motorists’ eyes as well as too many light poles along the highway, making the design prohibitively inefficient.

Instead, fixtures that do not meet full shielding requirements but come very close — defined as “cutoff” or “semicutoff” — that send just a little amount of light above the horizontal plane will be used on highways, she said.

“We do agree these are the best, latest lighting design concepts and certainly we want to do it,” she said. However, “there are no clear-cut answers at his point,” she said.

The advisory committee will use computer modeling to compare the aspects of different lighting designs, she said. Its findings will be issued in a report by August 2003, in time for the General Assembly’s 2004 session with the goal of an amendment be made to the law to accommodate these complex interstate design problems, she said.

At a minimum, motorists can expect to see no more of the floodlight-style lights on I-95 and other areas of the state that VOLT members have bemoaned, she said.

Interstate 66, when it is eventually widened, will have lights that adhere to the new standards, she said.

Like VDOT, Prince William County uses fully cutoff streetlights on non-interstate roads. The bulbs are noticeable by their flat under-surface. Prince William requests the cutoff bulbs for installations done by Dominion Virginia Power and Northern Virginia Electric Cooperative, said Mike Clark, Prince William public works street light coordinator.

Staff writer Chris Newman can be reached at (703) 878-8062.

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