Week after week, like clockwork, your trash seems to vanish into thin air: place the bin on the curb before you go to bed, and in the morning it will be empty. In reality, an entire fleet of garbage trucks roll around the city, collecting waste and keeping communities clean, often without anyone giving it a second thought.

These large, boxy vehicles may look simple. But they are sophisticated, highly engineered machines designed to repeatedly lift, shred and transport tons of trash. These heavy-duty trucks are equipped with hydraulic systems, compaction equipment, electronic controls, cameras, safety systems, automated lifting mechanisms, and braking and suspension systems designed for frequent stops. But how exactly do these high-tech machines on wheels do it? How do garbage trucks really work?

“They are built for some of the toughest jobs imaginable: stopping every few houses, lifting heavy loads hundreds of times a day, operating in all types of weather, and lasting for years under constant use, eight to 12 hours a day,” says Ryan Brettell, owner of Reliable Sanitation & Recycling in Raleigh, North Carolina. popular science.

Get to know the workhorses of waste collection

Garbage trucks come in a variety of designs and configurations. But in today’s residential neighborhoods, two types do most of the heavy lifting (pun intended): rear-loaders and side-loaders.

Rear-loading trucks are the classic garbage trucks that most people imagine, where workers grab and dump trash bags into the back by hand or use a mechanical dump truck to lift and empty the bins at the curb. Since becoming popular in the late 1920s and early 1930s, they have been a staple of the residential collection for decades and remain a practical and cost-effective choice in many neighborhoods.

However, in recent years, side-loading trucks have increasingly replaced rear-loading trucks in cities across the country, according to Ralph Sauceda, vice president of fleet and asset management at Republic Services.

Many side-loading trucks are equipped with a hydraulically powered robotic arm, usually positioned on the passenger side, that extends from the truck to lift, empty and return containers at the curb. Some side loaders are equipped with sensors that automatically pinpoint the location of the container and align the robotic arm, Sauceda says. But in others, the driver uses a joystick to manually align the arm. Overall, this design has made trash collection safer and more efficient, requiring only one employee, a driver, who does not have to get out of the cab, Sauceda says.

Scottsdale, Arizona, introduced the world’s first automated side loader in August 1969. Affectionately nicknamed “Godzilla,” the truck was the brainchild of Marc Stragier, then Scottsdale’s public works director, who sought to mechanize residential garbage collection in a city where summer alley temperatures often exceeded 120 degrees. The initial design needed a lot of tweaking (later models were given names like “Son of Godzilla,” “Litter Pig,” and “Trash Hog”), but in the late 1970s, automated side loaders took off.

“[Side-loaders] “They are very common in residential neighborhoods today,” says Brettell.

With both rear-loaders and side-loaders, once the trash is picked up, a powerful baling blade pushes it deeper into the cavernous interior of the truck, known as the hopper. These hydraulic compactors “dramatically” increase the amount of trash each truck can carry before it has to be unloaded, helping to reduce fuel use and operating costs, Brettell says. “Without compaction, trucks would be full after only a small part of the journey,” he adds.

The entire process of collecting, emptying and compressing is repeated “hundreds of times,” says Brettell, until the hopper is full. The driver then heads to a landfill, transfer station, recycling center or waste processing facility, where a hydraulic ejector panel (essentially a movable metal wall inside the truck) pushes the compacted waste back into a large mass. Then the vehicle will be ready for another route.

The people and technologies behind the trucks

Beyond these basic garbage collection components, many modern garbage trucks also feature a suite of onboard technologies, from cameras and mirrors to GPS and onboard diagnostic systems.

Behind the scenes, garbage companies often use optimization systems to plot the most efficient routes for their trucks, taking into account each vehicle’s capacity, expected traffic, number of homes, estimated amount of trash, unloading location and other factors, Sauceda says. Most Republic Service side-loading trucks, for example, can hold between 12 and 14 tons of trash, he says, and the average household produces about 140 pounds of waste (between trash, recycling and composting) per week.

Some companies, including Republic Services, are also adding electric garbage trucks to their fleets. They are equipped with the same hydraulic systems, only they run on batteries and electric motors instead of internal combustion engines, Sauceda says.

And while the driver may be the face of the operation, a much larger team (including dispatchers, maintenance technicians, environmental professionals, and operations staff) works behind the scenes to keep the process running safely and efficiently.

“Everyone who is new to the industry has almost the exact same thought: ‘How hard can it be? It’s just garbage,'” Sauceda says. “Oh no, it’s much more complex than just garbage.”

The unsung heroes of public health

Garbage trucks may not be glamorous. But, without these 40,000- to 60,000-pound behemoths thundering through the streets each week, our cities would undoubtedly be much dirtier, more dangerous, and less functional.

“The industry doesn’t always get a lot of attention, but its impact on quality of life is enormous,” Brettell says, adding that removing trash protects public health by minimizing pests, diseases and environmental hazards. “Waste management is one of those services that is almost invisible when everything is working well, but everyone notices immediately when it stops working.”

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