Flat tires can be inconvenient in the least and can sometimes be dangerous. If you get a flat, the first thing to do is pull over to a safe spot, whether you plan to change the tire or not. Remember that driving on a flat may damage the tire beyond repair. Some tires flattened by punctures may be able to be repaired. Plugging or patching can prolong the life of your tire and spare you the cost of replacement. Plugging uses a soft rubber stem and glue to seal the puncture hole. Plugging works only works on relatively small holes in the tire and won't work on sidewall punctures. Patches are usually more effective and longer-lasting than plugs, but they also usually cost a little more. A temporary tire sealant can sometimes help in an emergency, but it's no substitute for a proper flat repair. Contact a qualified mechanic or local tire specialty shop for more information on tire repair.