Curious Iowa: What are the weigh stations located along Iowa interstates used for?

Iowa’s highways are built to withstand a wide variety of vehicles, from compact cars to 18-wheeler semis and large farm equipment. They do have their limits, though, and according to the Iowa State Patrol, that limit is about 80,000 pounds.

“The weight deteriorates the roadway, so if you’re not abiding by the weight laws, it’s pretty much ruining our infrastructure in the state of Iowa,” said Lt. Neil Suckow, of the Iowa State Patrol Commercial Motor Vehicle Unit.

It’s also a safety issued, Suckow said, because hauling too much weight can cause strain on crucial equipment, like brakes, leading to potential dangerous crashes.

So why do the weigh stations along Iowa’s highways, which are used to check that large vehicles are following legal weight restrictions, never seem to be open? That’s what one reader of The Gazette wondered. They sent their question to Curious Iowa — a series from The Gazette that answers readers’ questions about the state and how it works.

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According to Suckow, the answer has to do with staffing and with the capabilities of the stations to let vehicles through without backing up traffic. We talked with him to learn more about the stations and how they operate.

Why are Iowa’s weigh stations closed so often?

According to Suckow, not all of Iowa’s 11 weigh stations — controlled by the Iowa Department of Transportation but operated by the Iowa State Patrol — are open and operating every day, mostly due to staffing. When they are operating, they are often closed to traffic while the trooper operating the scale performs a safety inspection.

Each area of the state schedules troopers differently, but in southeast Iowa — the area Suckow covers — a state trooper will be scheduled to work a weigh station once or twice a week. Typically, only one or two troopers is working each station at a time, Suckow said.

It takes less than a minute for a vehicle that is following weight regulations to be weighed pass through the station. If there is a weight violation, however, or if the trooper suspects another traffic violation — like with the driver or equipment — the vehicle will be stopped for an inspection, which can take up to an hour.

If there’s only one trooper operating the station, the station will have to be closed to additional traffic while the inspection is performed, to prevent traffic from backing up while drivers wait to get through.

“When you only have one person there, if they choose a vehicle in the first four that comes in, it's going to only be open for five minutes and then be closed for an hour,” Suckow said.

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Who is required to stop at weigh stations?

When a weigh station is open to traffic, any vehicle weighing more than 10,000 pounds is legally required to stop, but Suckow said the state patrol only takes enforcement action on vehicles that are being used in furtherance of business, like farm vehicles or semitrucks.

“Cars don’t need to stop. They’re going to be below. Dually pickups, if they’re not pulling a trailer, completely empty, depending on how big they are it’ll be close to 10,000,” Suckow said. “If they hook a trailer up, even if they’re empty, now that puts them over 10,000.”

If a business vehicle bypasses an open weigh station, the driver will face a moving violation, with a fine of $210.25.

What are the penalties for hauling too much weight in Iowa?

A vehicle that weighs more than 80,000 pounds can be subject to fines that range from $6 — for being between one and 1,000 pounds overweight — to $1,100 — for being between 19,001 and 20,000 pounds overweight. After 20,000 pounds, an additional five cents is added to the fine for every extra pound over the limit.

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There are also smaller weight limits for how much each axle of a large vehicle can be carrying, with 34,000 pounds being the limit for a tandem axle, and 20,000 pounds for a single axle. Fines for exceeding the weight allowed on an axle are double the fines for exceeding the total weight limit. So, if a vehicle was 60,000 pounds total, but 40,000 of those pounds were resting on a single axle — 20,000 more than allowed — the driver would face a $2,200 fine.

Suckow said weight violations are common, with troopers in southeast Iowa issuing at least one weight fine every day.

“Over the road trucks, normally, their violations will occur with tandems because they didn’t get their tandem slid correctly when they were loaded, based upon the product they’re hauling,” Suckow said. “You’ll see construction trucks, dump trucks, those kind of vehicles will violate weight laws. It kind of ranges. You’ll see it with all kinds of vehicles.”

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Comments: (319) 398-8328; emily.andersen@thegazette.com