Raised safety platform ramps should be designed so that vertical acceleration is kept in the range of 0.4 – 0.7 g for the desired operating speed. Vertical acceleration exceeding 0.7 g is considered too dangerous and may damage vehicles, and below 0.4 g is not enough of a deterrent to achieve the desired speed reduction. The vertical acceleration for each vehicle varies based on the vehicle type, their suspension system, tire pressure and seat softness.
Generally:
▸ 1:15 ⇶ 30km/h
► 1:20 ⇶ 40km/h
► 1:25 ⇶ 50km/h