ANN ARBOR, MI -- A lower proportion of young people have a driver's license today compared to their counterparts in the early 1980s — a trend not found among older age groups, a University of Michigan study shows.

In 1983, a third of all licensed drivers in the United States were under age 30. Today, only about 22 percent of drivers are twentysomethings or teenagers. Further, more than half of all drivers in 1983 were under age 40, but today that number has fallen to less than 40 percent.

"It is possible that the availability of virtual contact through electronic means reduces the need for actual contact among young people," said Michael Sivak, research professor at the U-M Transportation Research Institute. "Furthermore, some young people feel that driving interferes with texting and other electronic communication."

In a new study in the journal Traffic Injury Prevention, Sivak and UMTRI colleague Brandon Schoettle examined the changes in the United States from 1983 to 2008 in the percentage of persons with driver's licenses as a function of age. They found that young people not only account for a lower percentage of today's total licensed drivers, but that young drivers comprise a smaller portion of their age group as a whole, compared to 1983.

About 87 percent of 19-year-olds in 1983 had their licenses, but 25 years later, that percentage had dropped to about 75 percent. Other teen driving groups have also declined: 18-year-olds fell from 80 percent in 1983 to 65 percent in 2008, 17-year-olds decreased from 69 percent to 50 percent, and 16-year-olds slipped from 46 percent to 31 percent.

Drivers in their 20s and 30s also saw their ranks fall as a percentage of their age group population — down nearly 10 percentage points for twentysomethings and down about five percentage points for the thirtysomethings.

On the other hand, licensed drivers among older age groups (those over 40) have increased their numbers, as both a percentage of their population and as a percentage of total licensed drivers.

In 2008, those 70 and older comprised the largest group of drivers on the road — more than 10 percent — slightly higher than those in their 40s or 50s. Licensed drivers as a percentage of their age group population have risen for all groups over age 45 since 1983.

In 1983, between 84 percent and 88 percent of people in their late 50s and early 60s had a driver's license. Now those percentages are in the 95-percent range. The change is even more pronounced for seniors. Today, about 94 percent of those age 65-69 and 78 percent of those 70 and older have their licenses, up from 79 percent and 55 percent, respectively, in 1983.

"Overall, the future evolution of these changes will have potentially major implications for future transportation and its consequences," Sivak said. "Specifically, licensing changes will likely affect the future amount and nature of transportation, transportation mode selected, vehicles purchased, the safety of travel and the environmental consequences of travel."