We don't write much about trucks here at GreenCarReports.com, but our friends at PickupTrucks.com follow them obsessively. Now they've provided the data for an obvious but revealing truth: People drive better and more smoothly, saving gas, when they're being watched.

They report that truck fleets using the Ford Work Solutions' Crew Chief application, which lets fleet operators track not only the location but the driving behavior of their drivers, both save gas and drive more safely.

The data comes from Bill Frykman, the product and business development manager for Ford Work Solutions, which is offered in Ford's various commercial vehicles--including pickup trucks, vans, and the 2010 Ford Transit Connect small delivery van.

2010 Ford Transit Connect - media event in NYC, May 2009

2010 Ford Transit Connect - media event in NYC, May 2009

Fykman cites "fuel economy gains upwards of 20 percent", or 3 miles per gallon, as drivers improve their behavior once they know they're being tracked by the Crew Chief software.

"There’s decreased top speed, less engine idle time and more efficient operation of the vehicle," adds Frykman.

The data came from a construction crew running Ford F-150 pickup trucks. Fuel economy rose from the mid-teens to the high teens, saving more than 100 gallons per truck per year if each one traveled 10,000 miles per year.

Drivers also braked less harshly--up to 77 percent less often--because the trucks averaged lower speeds and drivers were aware of the monitoring.