Challenge: Maximum speed with a trailer or caravan

'80' is the number that sticks hardest with trailers — and that is exactly why the CBR exam designer slides it under your nose inside the built-up area. But 80 belongs outside the built-up area. With a trailer or caravan three fixed maxima apply per road type: 50, 80, 90. Once you tie those three to the right road type, you see through every shifted-number trap.