A run-flat tire is a pneumatic vehicle tire that is designed to resist the effects of deflation and to enable the vehicle to continue to be driven, although depending on the type of tire, at reduced speeds (i.e. 80 km/h or 50 mph) and for limited distances. They were originally developed for two-seat sports cars with little room for spare tires and jacks, but are growing in popularity for other vehicles because of their safety and convenience