We need the circular driveway to be wide enough for 1 vehicle (my guess is approx. 10 to 12 ft.), however I am uncertain on what the diameter needs to be to ensure that an average size car can make the turn. Thanks in advance for your assistance. A U-Shaped driveway or driveway is such a functional design. What dimensions should be used for a driveway? Please note: You are currently browsing img semi circle driveway exterior farmhouse with entrance that is 990x742px in size. This image is listed in half circle driveway landscape ideas category. What dimensions should be used for a semicircular driveway, 990x742 in 322.74 KB.