The garbage truck 4:00 AM brake squeal problem is very annoying, and demands an explanation. As a former engineering manager of EIS Brake div of Standard Motor Products, I would like to participate in this discussion. First, some of these trucks may be old, with front drum brakes, which may be in need of maintenance, but the real problem is the enormous amount of kinetic energy that must be dissipated in stopping very heavy trucks every 75 feet. When you study the worst case duty-cycle of motor vehicles, we find that UPS trucks, Mail Trucks (AM General), and garbage trucks that are constantly starting and stopping, represent the most difficult problems because of very high brake temperatures. All that Kinetic energy is turned into heat which is then wasted to the atmosphere. AM General trucks use silicone brake fluid (DOT 5) to prevent vapor lock and failure of the brake fluid. Brake materials have wear rates that can quadruple at elevated temperatures, and manufacturers improve the wear rate by adding metal filings to the pad material. When the government (DOT) made asbestos illegal in brakes, the industry went to less temperature tolerant materials, and included metal particles for better wear (Semi-metallic). The brake industry sued the DOT for not conducting proper economic impact studies before outlawing asbestos, and they won the case. But, by the time the asbestos ban was lifted, the industry had developed good substitutes, and there was little sense in adding litigation risk to the already litigious field of brake manufacturing.
Weekly brake maintenance and adjustment could greatly improve this acoustical problem, but would add to the cost of service. This cost burden is not easy to bear in a competitive bidding environment.
Joe Gordon

Thank you for this information Joe Gordon

I hear those noisy brakes every Monday when they come through our neighborhood around 4 am, then hear them again when they come through the neighborhood a half a mile away on a different day of the week. The noise raises the larger question of why do they have to pick up garbage at 4 am? I have lived in in lots of cities but never one that has a 4 am pickup. It may allow for easier pickup and a cheaper contract for the town but what is lost by residents lost productivity due to a 4 am wake up?

Safety, is my main concern for running earlier. If the trucks were to run during the day, Kids at bus stops, commuters racing to get where they have to go, all present a potential problem then add the stop and go of the garbage trucks. I would almost certainly assure there would be just as many complaints if the present contractor was working during the day. In the bigger cities the people are used to that hustle and bustle during the day. Also, in the cities they are working at night as well. I know this because i have been in the industry for MANY years. As far as the brake sound, it is simply the combination of drum brakes, and the starting and stopping repeatedly There is no way around this.

sk6619

Joe Gordon has addressed the noise issue. I personally don't have a problem with the timing of the work that needs doing, and all the more applaud the people who do this difficult (often freezing) job.

Adding to my previous post...Joe Gorden, former engineering manager of EIS Brake div of Standard Motor Products offers educated information about this topic.

The bottom line is this:
We don't need to endure the noise from large truck brake squealing. It's on the garbage/recycling truck companies to better maintain their vehicles.