For drivers who get anxious when cars grow bigger and bigger in their rear-view mirrors, cheap and easy help may be on the way - oval-shaped dots painted on the highway or hot-pink panels along the side of the road.
Test programs in Maryland, Minnesota and Pennsylvania aim to curb tailgating by using road markers that alert motorists to distances between vehicles. The markers serve as a tangible reminder of commonly taught driving guidelines such as the "two-second rule," which urges drivers to stay at least two seconds behind the car ahead.
Unlike the two-second rule, however, the road markers provide motorists with accurate, measured following distances.
The Minnesota Department of Transportation announced June 22 that a two-mile stretch of state Highway 55 about 40 miles northwest of Minneapolis has been painted with 94 white, oval-shaped "distance dots." Spaced 225 feet apart in a zone with a 55-mph speed limit, the dots are accompanied by signs reading "Keep Minimum 2 Dots Apart" and "2 Dots = 3 Seconds" - the latter being true if motorists stick to the speed limit.
Minnesota recently began recommending three seconds between cars, though it has recommended two seconds in the past, said Gordy Pehrson of the Department of Public Safety, which has worked with the transportation department on the project.
"Partially due to the aging population and faster, heavier traffic, three seconds is the best way to go," Pehrson said.
In Maryland, the state's Transportation Authority announced May 19 that an eastbound section of the Chesapeake Bay Bridge, about 40 miles east of Washington, D.C., would use technology similar to Minnesota's "distance dots." But its plan, called "Keep Your Cool and Pace Your Space," will exchange the dots for hot-pink panels along the side of the road.
The "Pace Your Space" program will use panels because they can be mounted at drivers' eye level and are easier to maintain than dots on the road, according to transportation spokeswoman Teri Moss. The panels were to be installed starting July 10, she said.
Accidents are the main cause of congestion on the Chesapeake Bay Bridge, a popular gateway to Maryland's Atlantic coast, especially during summer. Rear-end collisions accounted for 58 percent of crashes on the bridge between 2002 and 2004, with 70 percent occurring in eastbound lanes, Moss said.
The Maryland and Minnesota programs owe allegiance to Pennsylvania, which first used anti-tailgating road markers in 2000 on a rural stretch of U.S. Route 11 near the town of Bloomsburg, about 100 miles northwest of Philadelphia - with eye-opening results.
Like Minnesota's project, the Pennsylvania test site used white dots painted on a two-lane road. Pennsylvania, however, still recommends the two-second rule, and the dots on Route 11 are spaced 115 feet apart - or two seconds, if motorists follow the road's 45-mph speed limit.
The program resulted in a 65-percent drop in accidents from November 2000 to March 2001 compared with the previous year, according to the Pennsylvania Department of Transportation. That earned the program a National Highway Safety Award in 2001 from the Federal Highway Administration (FHWA).
In 2003, the FHWA separately listed the program as a "Low-Cost Traffic Engineering Improvement" that other states could replicate. Officials in Maryland and Minnesota developed their programs based on Pennsylvania's success.
According to the FHWA's 2003 listing of the Pennsylvania program, installing one test site costs $1,892, including equipment, signs and labor. The recently unveiled site in Minnesota used a $25,000 federal grant to pay for the installation and a public information campaign. Maryland has not disclosed the cost of its Chesapeake Bay Bridge plan.
Since its initial success in 2000, Pennsylvania has experimented with the dots on a handful of other sites, including on Interstates 80 and 81, according to Steve Chizmar, a state transportation spokesman.
But success has been greater on two-lane roads than on interstates and depends heavily on police enforcement of proper following distance, Chizmar said. South Centre Township, Pa., police, who monitor the test site on Route 11, have issued about 15 citations a month for aggressive driving since the dots arrived, according to Chief of Police William Richendrfer.
"It comes down to enforcement," Chizmar said. "You have these hard-nosed, aggressive drivers who feel they're above the law. They're going to ignore warnings."