Drawn by the desire to stay on the road and lower insurance costs, a growing number of older Americans are signing up for driving school - online.

Adult online driver’s education classes have become the fastest way for adults to brush up before a driving test, or to secure a discount on auto insurance.

AARP says by June of this year, more than 40,000 older citizens had signed up for their online class. The typical class costs $20, and takes four to eight hours to complete.

Those serious about staying behind the wheel longer as they age can take a more comprehensive online road course for about $50 to $100 an hour.

For more information on the senior driver safety course, click here.

Information from NBC News was used in this report.