Improving America's broken highways need not require massive public works expenditures like Boston's Big Dig. Some basic re-engineering of existing roadways aimed at boosting highway safety will also ease traffic snarls significantly.

For example, a joint project between the Virginia Dept. of Transportation (VDOT) and the Insurance Institute for Highway Safety (IIHS) shows that simple changes in traffic management at heavily travelled urban intersections can cut the number of crashes, improving safety and reducing congestion, at relatively low cost.

“Urban roads weren't built to accommodate today's heavy traffic,” says Richard Retting, IIHS's senior transportation engineer. “They've evolved as traffic has increased, and they haven't always evolved in the best way to enhance safety and ensure a smooth flow of traffic.”

To override this natural selection, Retting says urban arterials must be studied “to pinpoint where crashes are occurring frequently and then identifying potential solutions, looking first for less costly measures that can be implemented more quickly than major re-engineering.” These solutions might be as simple as reducing speed limits on some stretches or adding left-turn-only lanes.

The urban-intersection project studied traffic on Leesburg Pike in suburban Fairfax County, VA. At two of the six intersections studied, where crashes averaged 8.7 and 4.6 per year, protected left-turn lanes cut accidents to zero.

At the other four spots, marking pavement with turn arrows reduced annual crashes from 8.3 to 3; extending merge lanes reduced annual crashes from 8.2 to just 0.9; elimination of a bus stop reduced the annual crash rate from 3.5 to 1.4; and widening a shoulder area for a bus stop reduced annual crashes from 4.3 to 2.5.

“We applied some straightforward engineering improvements that were effective and not very costly,” states VDOT spokesperson Connie Sorrell. “Now we're looking to use these and similar measures elsewhere.”