Are they intentionally squeaky? Seems that any time I see one, the brakes are squeaking.
Just a WAG but big trucks need big brakes. Garbage trucks use theirs a lot more than something that drives down the road for miles between uses so they’re more worn out.
Thought it had something to do with making people more aware of their presence
Also, and this goes along with what DD said, they don’t just have to stop at every light/stop sight/corner, they stop at. every. house. So if they are loud you hear them every 8 seconds from one end of the block to the other. If the brakes on another truck are loud you might only hear them once or twice.
Also, a cheap truck owner can delay repairing the brakes without too much concern – they don’t get up too much speed when they’re stopping about every 20 feet along the alley.
Trucks subject to frequent stops/starts and which are built to commercial specs, such as dump trucks, are also more likely to be equipped with brake pads that are more prone to squeaking, as they might have more metal in the actual pad for durability. Combine that with intense start/stop use (dirty, hot), and one would fully expect them to be squeaky.
City buses also have notoriously squeaky brakes.
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