# Determining minimum dimensions for circular driveway

What should be the minimum dimensions for a circular driveway on a 100' wide property, including the radius?

The property is flat, and the house will be wherever we want to place it relative to the circular driveway. Largest vehicles using it will be Ford Explorer, Toyota 4-Runner, so driveway will about 9'-10' wide. We want enough space for a small lawn between the driveway and the house. I guess the real question we have is: what is the minimum distance the outside curve would be on the 100' wide property, so we don't use up too much front property for the driveway itself?

Architects and traffic engineers have used “Architectural Graphic Standards” by Ramsey and Sleeper since 1932. It’s been updated every 4-5 years by The American Institute of Architects and John Wiley & Sons, Inc.

They recommend a minimum INSIDE radius of 12’ for sports car, 15’ for sedan, 19’ for SUV’s and Cadillacs and 22’ for pickup trucks with small boat trailers (boat=16’ or less).

They recommend a minimum OUTSIDE radius of 22’ for sedans, 29’ for SUVs and Cadillacs and 41’ for pickup trucks with small boat trailers.

We do not provide a curb between the driveway and walkway on the outside radius for “extra” cushion.

If the space is drivable right now I would go there with a friend and the vehicle in question. Load up your friend with a dozen stakes and 2-lb mall. Do some experimenting. Find out what is comfortable.

Solution #2. Find a little used intersection in a quiet neighborhood or an abandoned parking lot. Take a friend and a can of spray paint. Do some experimenting. Find out what is comfortable to you.

Specifications are available on all automobiles that state the minimum turning radius of the vehicle. I would probably start with the minimum x2. Then add what is comfortable for you. Then you would consider all the things isherwood listed above plus the things that have now, through the experimenting, become apparent to you. Good Luck. P.

I have an inside radius of 15.5 ft ( 29 ft diameter). It works for vehicles up to the size of a pickup truck, driving carefully , no curbs. The pavement is 10 ft wide for most of the circle. I think it is about the smallest practical radius one can use.