With 14 trucks on the road — trucks that go home with employees on weekends — Troy Marshall found himself wishing he knew where the vehicles were when not at work. “I had no idea what was happening with [the trucks] after hours,” says the president of Marshall Roofing, in Lorton, Va. So, two years ago, he had global positioning system (GPS) equipment boxes and antennas installed at a cost of $600 apiece, plus $35 per month in leasing fees. He figures that one extra job per truck per month pays for that.

Why It's Worth It Knowing where all your vehicles are at any given moment doesn't take psychic ability, just technology. Several companies offer GPS packages, and a number of replacement contractors, such as Marshall Roofing, now use them. For some, the primary purpose is to reduce the need for frequent vehicle replacement. Another is simple logistical efficiency. For instance, DryHome Roofing and Siding in Sterling, Va., uses GPS to “make a good match” between customers and crew members, says owner Steve Gotschi. By knowing where everyone is, he says, “we can get on service calls much quicker.” The contractor also uses the system to check an employee's whereabouts when a customer says that no employee showed up.

GPS can also go a long way toward preventing theft or aiding in stolen vehicle recovery. Two years ago, Clear Choice Windows in Miami installed GPS in its vehicles after a van filled with tools was stolen overnight from outside a worker's apartment.

System Capabilities The software that Marshall uses does more than track the latitude, longitude, and speed of each vehicle and show where it is on an online map. It can generate reports on everything from when the trucks start and stop to excessive idling to maintenance needs.

Systems can be programmed to signal the office, via e-mail, when drivers speed.

“Now I'm able to know where my trucks are 24 hours a day,” Marshall says. “If someone calls and says an employee was supposed to be there at 11 a.m., we can tell them that he's 3 miles from the house.” He also doesn't worry about the trucks being used on weekends.

But systems aren't foolproof. There may be areas where GPS simply doesn't work well. Antennas can become dislodged or broken. And there are glitches: Recently, the GPS used by Clear Choice Windows located one of the company's vans in the water by Cuba, going 95 mph.