Buses and Raised Platforms: Getting the Design Right

Raised platforms are among the most effective tools for reducing vehicle speeds, but when a bus route is involved, getting the design right means more than just choosing the appropriate platform height; you must also consider the full platform profile.

Platform performance comes down to three interacting elements: height, grade and length. Higher platforms generally deliver greater speed reduction, but grade is considered the primary driver of vehicle speeds, while longer flat-tops reduce the risk of underbody contact (bottoming-out).

Why grade matters so much

Ramp grade has a direct relationship with expected travel speed: a 1:15 grade is associated with speeds around 30 km/h, 1:20 with 40 km/h, and 1:25 with 50 km/h. Where a platform incorporates a pedestrian crossing, getting speeds down to 30 km/h should be the safety objective, since higher speeds exponentially increase the risk of fatal crashes.

Bus-friendly doesn’t mean better

Lower “bus-friendly” profiles (often 75 mm) are sometimes used to protect ride comfort, but evidence shows that lower, flatter profiles can significantly reduce the speed-reduction benefits. As a starting point, guidance suggests a 100 mm platform height, 1:15 ramp grade, and a minimum 3.5 m flat-top length with wheelbase, overhangs, underbody clearance, road grade and vehicle dynamics all checked against the specific design bus.

Check out the Buses and Raised Platforms Factsheet (attacehd below) to learn more about the right approach to Raised Platform design.