OKLAHOMA CITY (AP) - Troy N. Smith, the founder of a drive-in chain that became Sonic restaurants, has died in Oklahoma City. He was 87.

A spokeswoman for the Oklahoma City-based restaurant chain says Smith died Monday at an Oklahoma City hospital after a recent decline in health.

Smith started the Top Hat root beer stand in Shawnee, Okla., in 1953 and later converted it into a drive-in restaurant where customers used an intercom speaker system to place orders from their cars.

He eventually changed the name to Sonic Drive-Ins. There currently are nearly 3,600 restaurants in 42 states.