So, in the 1950s and 1960s and possibly after people brought their hot rods built for street racing with slicks (which were super wide tires for traction when you burn rubber in a race on the streets). If you Have watched Grease or American Graffiti then you know what it was like in the 1950s and early 1960s at Drive Ins and regarding "Cruising" and Street Racing too.
On Fridays and Saturday nights when I was 12 or 13 my friend lived right behind Bob's Big Boy then and so we would climb the 8 foot tall cement block wall to see all the drag racers with their pretty girls on Friday's and Saturday nights then. And sometimes people would peel rubber (burn Rubber) going out of the parking lot which was always a treat to see along with the expensive street racers that people had mostly built up themselves into full Street racing cars.
I was 12 in 1960 and 13 in 1961 around the time we sat on the wall to watch all the beautiful young people in their fancy race cars at night on weekends having fun there and sometimes there were even fist fights over girls in the parking lot there too then which was also interesting to watch for someone 12 or 13 years old too then.
So, there were both Drive in Theaters and Drive in Restaurants then in the 1950s and 1960s especially.
Even in 1977 the first time I saw the original Star Wars movie with my then 3 year old son it was at the I believe it was called the "Sunland Drive in Theater" up against the mountains. Sunland is next to Tujunga where I went to 1st and 2nd grade when I was little at Pinewood Avenue Elementary School. That would be 1954 and 1955 when I was in 1st and 2nd Grade then.