The Dept. Of Transportation estimates that: *5 million gallons of gasoline is lost each DAY due to under inflated tires. *24,000 accidents a year are attributed to tire ‘failure’.
Regularly checking your car's tire pressure is one of those things that people tend to forget because they don't realize the importance of doing so. Tires have an extremely small surface area in comparison to the rest of the vehicle, so they must be kept in optimal condition in order to operate safely.
You should always check your car's owners manual of the service placard located on the driver side door for the correct tire pressure specifications. In hot temperatures you should also inflate your tires 3 - 4 psi higher than you normally would during the cold months.
Simply stated, if your tires are under inflated it causes your vehicle to work much harder which results in awful fuel mileage. It can also lead to early tire wear and possible failure which can be extremely dangerous.