Nearly a third of new vehicles no longer come with a spare tire as standard equipment, a number likely to increase as automakers seek to reduce weight in cars to improve fuel economy.

“This is a major issue for Michigan motorists who find themselves stranded on the roadside," Susan Hiltz, public affairs director for AAA in Michigan, said Wednesday. "They can no longer rely on their tire inflator kit and require vehicle towing.”

AAA found that 28% of the 2017 model year vehicles sold don't have spares, down from 36% of the 2015 model year vehicles sold.

But it was up significantly from just 5% of 2006 model year vehicles.

Will spare tires eventually disappear altogether, in a similar way features such as cassette tape decks have?

To be prepared, AAA recommends car owners know whether they have a spare before they need it, and regularly check their tire pressure. Many new vehicles, the auto club said, also are equipped with tire-pressure monitoring systems that alert drivers to low pressure.

Some vehicles also now come with standard run-flat tires, which offer 100 miles of range to find a repair shop. These tires cost more and are reinforced so when they lose pressure they can still support the car's weight.

When there is a problem, many customers call for roadside assistance rather than change a tire. An increasing number of younger drivers — about 20% — don't know how to change a flat tire, according to an earlier AAA study.

The drivers who do know how to change a tire tend to be men — about 97% — in contrast to 68% of women.

Now, instead of spare tires, some automakers are now including tire-inflator kits that can plug small leaks. But the kits do not work as a temporary fix if the tire blows out or the damage is to the sidewall. They expire after 4 to 8 years.

Contact Frank Witsil: 313-222-5022 or fwitsil@freepress.com.

AAA tips for flat tires

• Check whether the car comes with a spare when you buy or lease a car

• Inspect tires regularly, including the spare, for proper inflation.

• If there is no spare, understand how to operat the tire-inflator kit.

• Check expiration dates on tire inflator kits, which last abuot 4-8 years.