It's quite amazing what kind of traffic rules cities seem to come up with in the States. I was passing through one town in Texas that had signs up "Use of motor break prohibited by city ordinance."
HTB.
Not at all uncommon. "motor break(sic)" refers to a certain type of diesel-engine-based brake. They are very noisy, and this is a noise-pollution/quality-of-life regulation in many areas. Commonly called "
Jake Brakes" after the company that makes the most commonly-used kind, but
that company complains to municipalities that put up "Jake Brakes Prohibited" signs, since other companies also make them, and since not all Jacob-manufactured braking products are noisy engine brakes.
That sign does not mean "you can't use your brakes to slow down" - wow, how stupid do you think we are here in the States?
It just means that big rig truckers can't use their noisy engine brakes within city limits out of respect for the noise laws. If they need their engine brakes inside a populated area they're going too darn fast.
How do I know this? I live just the other side of a noise-reduction dirt berm from an interstate highway that has an 8% 8-mile downhill. We have that same regulation on that stretch of road to allow people to have some peace and quiet. Actually it's an "engine brake mufflers required" rule - they can use them if they are properly set up so that don't sound like machine gun fire. I regularly hear the trucks ignoring the rules. Better than having their regular brakes burn up and the truck go runaway, which happens often enough unfortunately.