On the toll road, the cost of the vehicle is based on the height at the point through the centre of the front wheel. Below 1.3mts is classed as a car. Transporters are right on the cusp. If your lowered enough you're ok, I go through as a car every time now. In my old van sometimes if I was carrying enough or breaking hard as I entered the lane I got away with it. Other times I was no so lucky