The car turns around an invisible point
When you steer, the front wheels point in different directions from the car’s body. That makes the car follow a curved path rather than move sideways. In a slow, tight turn, the rear axle follows a smaller arc than the front: the rear wheels “cut in” toward the curb, while the nose swings outward.
The geometry depends on the wheelbase—the distance between the axles—and how sharply the front wheels can turn. Together, they determine the car’s turning radius. But fitting the tires into a gap is only part of the problem: the car’s corners also sweep through space as it rotates.
Why reversing changes the fit
A single continuous turn may bring one end into the space while sending the other too close to a neighboring car. Moving forward and backward lets the driver change the car’s angle in stages. Each change shifts the paths of the front and rear corners, making room for the next part of the turn.
That is why a useful reference point is not just the curb or the gap’s edge, but the position of the car’s rear axle and the clearance around its front corners. The tires trace arcs; the body occupies a wider envelope around those arcs.
The space has to fit the whole sweep
A gap can look long enough for the car and still be difficult to enter if there is little room to turn. The driver needs space for the nose to swing out before it swings back in, while keeping the rear wheel from clipping the curb. A few small corrections work because they distribute that rotation across several movements.
So parallel parking is not simply about squeezing a rectangle between two others. It is about guiding the car’s entire outline through a sequence of curved paths without letting any corner run out of room.
