The truckers who bring the goods t your local grocer aren't always happy with how the companies treat them. Stephen Chernin/Getty Images

Since the ELD mandate came into effect in December 2017, truck drivers have been pressed for time.

As a result, many of them are refusing to work with companies that keep truckers waiting for hours to load or unload their trucks.

The most-disliked retailers, according to a Zipline Logistics survey of 150 trucking companies, are all grocery stores.

When Zipline Logistics asked employees from 150 trucking companies around the country this fall what companies they refuse to work with, one type of retailer kept getting mentioned above the others: grocery stores.

"Any of the big grocery places, they're out to mess with you," Lexington, Ky.-based owner-operator Chad Boblett told Business Insider. "They create an atomposhere of animosity when dealing with them."

Truckers told Zipline in the survey that grocery retailers like Kroger, Walmart, C&S Wholesale Grocers, and Safeway takes hours (sometimes even days) to unload their trucks and might not pay drivers for how long they spend at their warehouses.

Read more: Rest breaks are a 'drag on the economy,' and the federal government says California truck drivers don't need them

Truck drivers are particularly aggravated by detention - being stuck at warehouses waiting for one's truck to be loaded or unloaded. Detention is a suck on drivers' time and how much they can earn in a given day.

Nearly two-thirds of carriers said in a DAT Solutions survey that they or their employees had been regularly detained at docks for more than three hours, but only 3% said they received payment most of the time from the shipping companies for keeping their workers waiting.

What's so bad about grocery stores?

Andrew Lynch, co-founder and president of Zipline, said grocery stores likely got such a bad rap in the survey because Zipline mostly works with grocery and retail companies.

Lynch also said grocery warehouses have more complicated supply chains than other retailers. He explained:

If I bring in a truckload of product from a customer that makes sparkling water, that truck load might be 28 pallets and six flavors.

When that truckload gets to the grocery distribution center, they're taking the pallets, then breaking down them down for a localized distribution center or the grocer. That might have to be broken down and then separated into 150 more pallets.

As a result, workers at grocery warehouses are often stretched thin. "It's not that these grocery warehouses are maliciously behaving," Lynch said. "They're operating the way they have to operate."

Fewer truckers are available for work, and that's forced retailers to accommodate their needs

The US was short some 36,500 drivers in 2016, according to a 2017 report by the American Trucking Association (ATA).

The ongoing truck driver shortage became more pronounced this year following the implementation of the electronic logging device mandate, which ensures that truckers don't drive more than 11 hours a day in a 14-hour period.

The law "has drastically limited the flexibility drivers can build into their activity and tightened the constraints that diminish their operating efficiency," Lynch said .

Less trucking labor means that truck drivers are increasingly able to call the shots when it comes to warehouses that are wasting truckers' time. Zipline found in its survey that 77% of carriers have become more selective in the companies that they're willing to work with.

Thanks to a labor shortage, truckers are increasingly able to call the shots. Bonita R. Cheshier/Shutterstock

Drew McElroy, CEO and co-founder of Transfix, told Business Insider that truckers just won't move freight for companies if they're not hospitable to drivers.

"There are places that trucking companies will not pick up from," McElroy said. "'I don't care if you pay me twice what the guy across the street is paying me, I'm just not going there.'"

So, major companies have strove this year to become "shippers of choice," lavishing free soda, snacks, and resting areas for truckers.

But Lynch said it all still comes down to ensuring detention time is kept to a minimum.

"It doesn't really matter how many free snacks or how many free Diet Cokes you have," Lynch said. "If you're taking up four hours of a driver's time, you're ruining their day. And no amount of free pretzels can make that up."

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