What is the appropriate distance between the left and right sides when reversing into a parking space?

[AliceFitz]

For the Subject 2 driving test, the optimal distance between the corner of the parking space and the vehicle body when reversing into the space is 30cm. There may be some error when observing the distance between the vehicle body and the corner of the parking space through the rearview mirror. Estimating the distance between the rear wheel's contact point and the corner of the parking space via the rearview mirror can be inaccurate, so regular practice is needed to account for this discrepancy. Relevant details include: failing to follow the prescribed route or sequence results in disqualification; the vehicle body crossing the line results in disqualification; failing to properly reverse into the space results in disqualification; stopping midway results in disqualification. Tip: Start reversing by turning the steering wheel one and a half turns to the right, and observe the top of the wheel in the right rearview mirror—it should be about 40cm from the right line of the parking space to ensure the right side does not cross the line when reversing into the space.