An automaker trend to improve fuel economy is creating an unnecessary hassle and forcing some drivers to shell out more money.

New research from AAA shows that 28 percent of 2017 models don’t come with spare tires. More companies are swapping out spare tires for tire repair kits, turning a routine fix into a drawn out problem for some drivers.

Most kits release a sealant into the tire to patch up small holes and then pump air into the tire. It’s a temporary solution until the driver can get help, but those are repairs the kit can make are limited and can’t help in more serious situations.

According to experts, the kits don’t work for blown out tires, big gashes or holes, or if a car hits a curb because they aren’t always reliable.

Experts say that most people don’t know their car isn’t equipped with a spare tire. One driver we found looked in her new Cadillac for her spare and found out that she only had a repair kit.

Last year, AAA responded to more than 450,000 calls from drivers without a spare tire.

Some high-end cars have run-flat tires giving drivers anywhere from 10 to 50 miles to find help, depending on the damage, but they’re more expensive to replace.

AAA also found that nearly 20 percent of U.S. drives don't know how to change a flat tire.