In the early days of the motor car, testers would measure a car's acceleration in 10mph increments. E.g. 0-10mph, 0-20mph, etc. As cars became faster, it became more common to measure them from 0-50mph and then 0-60mph. In Europe, most manufacturers measure their cars from 0-100km/h, which translates to 0-62mph. It's rare to accelerate to 62mph from a standstill in real-world conditions but it's a useful yardstick for comparing the performance of cars and more relevant than a top speed figure.