New automobiles are reaching dealerships with all manner of sophisticated lifesaving technology, like collision-warning systems and automatic braking. But older cars can be outfitted with similar systems, too, and a study suggests it can make driving safer for you — or your teenager.

“This can be a great way to get the safety benefit of crash-avoidance technology at a reduced cost compared to a new car,” said Ian Reagan, the author of the study and an official at the Insurance Institute for Highway Safety, a research group funded by the insurance industry.

Such technology could be particularly valuable for teenage drivers because mile after mile, the system would remind the driver of safe practices like using turn signals and not following too closely, Mr. Reagan said.

“They could learn early on,” he said. “Safer driving behavior from early on that could stay with them as they mature.”