It's called "MyKey," and Ford announced this week that it will be a standard feature starting next year on the 2010 Ford Focus and other Ford, Lincoln and Mercury models.
Ford said MyKey is "designed to help parents encourage their teenagers to drive safer and more fuel efficiently, and increase safety-belt usage."
It said the key can be programmed to limit the car's top speed, sounding chimes at 73 kph, 89 kph and 105 kph.
The car's top speed can be restricted to 130 kph.
Another feature disables the car's audio system until seat belts are fastened or limits audio volume to 44 percent of total volume.
"MyKey can help promote safer driving, particularly among teens, by encouraging seat belt use, limiting speed and reducing distractions," said Susan Cischke, a Ford group vice president.
Ford said a survey conducted for the automaker by Harris Interactive found that 50 percent of the parents of teen drivers said they would allow their children to use the family car more often if it was equipped with MyKey.
Ford said the key is programmed through its vehicle message center, which also controls the anti-theft system.
When MyKey is inserted into the ignition, the system reads the transponder chip in the key, identifies the pre-programmed code and enables the selected driving modes.
If MyKey isn't enough for anxious parents, Global Positioning System devices have been on the market for some time which allow parents to monitor every move of their teen-age driver.