The road designer says roads have to meet certain criteria to handle various speeds.
“We have to meet certain design rules such as sufficient parking room on the sides of roads, falling under max bend radius for the corner itself, and conforming to maximum changes in elevation for that particular road,” he says.
“For instance, quality assurance requirements for a 100km/h road has things in it such as placing a 3m rule over any longitudinal direction of travel and the gap between the ruler and road not exceeding a certain amount.
“That said, when we tested a bunch of 100km/h roads built previously this measurement didn’t hold up.
“Yes there are rules that need to be met in order to class a road for 100km/h. However local council and or the police can change it for no given reason.”