If you’re buying a new vehicle, you might want to look in the trunk.    As car markers look to reduce vehicle weight to help improve fuel economy, some are looking at the spare tire.

AAA says 13% of all new vehicles sold in the first half of 2011 had no spare at all. Half of last year’s models had a temporary spare, also known as a donut tire, and 7% had run flat tires.

Jenny Robinson of AAA Mid-Atlantic says   vehicle owners may not be aware of the trend until they have a flat.  She says they already see a lot of tire service calls and that number could increase with more people driving cars that do not have a spare.

Robinson says if your car doesn’t have a spare, make sure you have an alternative like an emergency sealant and inflation kit or run flat tires.   She says you need to know what’s going to be practical for your needs.  The run flat tire allows a car to be driven to a safe location when the tire becomes flat.  The sealant also has limitations, and does eventually lose its effectiveness and should be replaced periodically.