There’s nothing more off-putting than a rolling road. Yes, putting your car on the dyno is a great way to see what power it’s making. But it’s deeply unnerving to stood next to a car that going at full chat while not actually moving at all. It’s just… weird.
Plus, if something goes wrong, the car is right there. The speedo might say 150mph, but the car is actually very much stuck to the spot. Like this Mustang. That blew a tyre. While going 150mph. On the spot. Urgh.