The proper dimension of a standard parking spot is 9 feet wide by 18 feet long. The dimensions of a compact car parking spot are 8 feet wide by 16 feet long. To practice parallel parking with cones that do not have a set dimension, the standard length is recommended.
Parking spots can vary in length from standard sizes to compact car sizes to parking spots designed to accommodate 18 wheelers. Vehicles themselves also have varying sizes. Practicing using the same vehicles helps drivers familiarize themselves with the vehicles dimensions and ultimately makes parking easier than parking with cars of different lengths.