Vertical deflection is not just for low-speed roads. Raised safety platforms or raised intersections are increasingly being used on high volume, high speed (60km/h +) arterial roads.

Some specific tips for raised intersections or safety platforms on arterial roads:
► Platform height (desirable) 100mm. 150mm in lower speed environments.
► Platform length – the flat section (i.e. plateau) needs to accommodate a standard passenger vehicle, however if there is a high percentage of heavy vehicles platform lengths to be extended so that the rear wheels of trucks are on the table before the front wheels reach the departure ramp. 
► Ramp grades (divided carriageways): 1:15 for 30km/h, 1:20 for 40km/h, 1:25 for 50km/h.
► The grade of the departure ramp should provide for smooth exit (1:35).
See VicRoads RDN 03-07, Austroads AP-R642-20 or the Safe System Solutions Pty Ltd fact sheet ( for more info.
Video credit: Katerina K Latrobe News