A digital LED billboard along Route 146 South in Providence rotates its ads.

The Providence Journal / Kris Craig

PROVIDENCE — After a barrage of criticism and the appointment of a new director, the state Department of Transportation has stopped issuing permits for LED billboards, which critics say are unsightly and a dangerous distraction for drivers.

Jerome F. Williams, the DOT director Governor Carcieri appointed in December, said the agency won’t approve any more permits for the brightly illuminated new generation of billboards, at least until a federal study of the signs’ impact on safety is completed.

Doug Hecox, a spokesman for the Federal Highway Administration, said the study will probably be completed in 2008 or 2009, and is intended to address a lack of knowledge about the safety implications of the new billboards.

Spokesmen for the governor and Williams made it clear that neither of them is enthusiastic about billboards.

“The governor would prefer fewer billboards rather than more,” said Carcieri’s press secretary, Jeff Neal, “and he is not in favor of additional LED billboards.”

Despite Carcieri’s feelings, the moratorium on permits is a big shift at the DOT. Under Williams’ predecessor, James R. Capaldi, another Carcieri appointee, who retired in December, the agency granted permits for four LED billboards and was in the midst of adopting regulations that could have allowed more.

That process was interrupted when critics, including another state agency, the Office of State Planning, objected to the draft regulations at a public hearing in October.

The DOT’s temporary moratorium, meanwhile, may not mean a break in the dispute. Critics continue to argue that the DOT granted the four permits in violation of the state’s existing outdoor advertising law, and say they should be revoked.

The four LED billboards were “illegal from the beginning,” said Sen. June Gibbs, R-Middletown, a legislative sponsor of the existing law. She said the legislature had no intention of authorizing the electronic billboards, and that the DOT acted in error.

“Those permits were issued in error” and should not be renewed, agrees Jonathan Stevens, the acting executive director of the group Preserve Rhode Island.

When LED billboards started turning up several months ago, Stevens said, “It came as a shock” because those who worked on the outdoor advertising law, passed in 1990, thought the issue was settled.

Stevens called the new billboards “an affront to the sensibilities of every Rhode Islander,” and said that “the public trust has been violated.”

A prized tool of modern advertisers, LED billboards are dramatically different from conventional ones. Named for the light-emitting diodes that make up their image, they are much brighter than conventional billboards. They also allow the rapid cycling of different messages, presenting a whole new image every few seconds. The result is that a driver who would have seen one billboard for a few moments sees a series of images a few seconds apart.

A light-emitting diode is a semiconductor device that emits a bright light using a modest amount of electricity. Along with the handful of LED billboards operating in the state now, LEDs are visible in the new traffic lights that the DOT has installed around the state to save money. Unlike an old-style traffic light with a single bulb and a colored filter, the LED traffic lights can be recognized by the dozens of tiny LEDs that together make up the signal light.

The color of an LED’s light depends on the material in the semiconductor. Many blue, green and red LEDs are grouped together, with the colors used in different combinations to produce full-color images.

Of the four LED billboards the DOT approved last year, three are operating, Williams said. They are on Route 195 in East Providence, Route 95 in Warwick and Route 146 in Providence. The fourth will be located on Route 10, according to the DOT.

The debate over them focuses on safety and aesthetics.

Critics say that the attributes that advertisers like — the LED billboards’ greater ability to attract and hold attention and to rapidly present multiple messages — make them a dangerous distraction for drivers.

The outdoor advertising industry at once denies that the new billboards distract drivers while emphasizing their attention-grabbing ability to potential advertisers. “LED billboards combine bright, vibrant color with motion visuals to grab the attention of drivers,” says the Web site of RGB Spectrum, an Alameda, Calif. company.

“Ten-second video messages running at 30 frames per second are the future of out-of-home advertising,” says another advertising company, the Spokane-based Emerald Outdoor Advertising. “The motion attracts the audience’s eyes and the length of message is an appropriate time to communicate in the out-of-home environment. As messages cycle throughout the day, passing traffic is offered a continuous array of messages. Each billboard location never gets stale as customers view to see ‘what’s next.’ ”

According to the industry, 94 percent of people passing digital billboards can recall them while only 43 percent recall conventional billboards.

The safety question, Williams said, is where “I want to see hard facts,” which he expects the Federal Highway Administration to produce.

Hecox, the federal agency’s spokesman, said that’s what his agency is trying to provide. “The FHWA does not have data to support decisions about the safety or risk posed by the new billboard technologies,” he said.

Whatever the outcome of the safety debate, critics denounce the brightly shining billboards as visual pollution that would damage the qualities that make Rhode Island a pleasant place to live. They said the new billboards would also make it less attractive to others — like paying tourists.

“It’s a blight on the landscape,” said Stevens. “Heritage tourism is one of our most important industries.”

Williams said he’s also sensitive to the other side of the issue, too.

“I’m not in favor of billboards,” Williams said. Signs, he said, should be “informative” and help travelers get to their destinations.

blandis@projo.com