It's a common sight along Florida's highways and byways: dogs riding unrestrained in the back of pickup trucks.

But under new Florida legislation, that practice would be banned.

A video that went viral on Facebook a week ago shows a somber-looking dog chained to the top of a cage in a trailer being towed on Interstate 95 in Flagler County (link to Facebook video — warning: includes profanity). The dog in the video was "tethered," but it raised awareness of the safety of dogs being transported in vehicles.

The measure, SB 320 by Sen. Greg Steube (R-Sarasota), comes amid a steady stream of preventable deaths. The Humane Society estimates 100,000 dogs die every year as a result of being thrown from the back of pickup trucks.

If the legislation becomes law, pickup drivers who fail to crate or tether dogs riding in their truck's bed could be cited for a nonmoving violation, which carries a fine of $30. But the penalty, some animal rights activists say, is less important than the norm the crackdown would set.

"Even if a car or truck goes to an emergency stop, like hard brake, I'm throwing him in the floorboard a lot," Denise Nuckles said of her dog. "Think about it: If he were in the back of the truck, he could go over the side so easily."

The bill, however, would override scores of local ordinances that take a tougher line by outlawing even the tethering of dogs in the back of pickups and trailers, the result of a "pre-emption" clause in the legislation.

The Republican-controlled legislature's efforts to invalidate local regulations are currently being challenged in court.

"When the state overreaches and takes away our ability to make decisions that we believe are in the best interests of the people who elect us, that's bad for democracy," said Tallahassee Mayor Andrew Gillum, a party to a lawsuit concerning the state's pre-emption of local gun ordinances.

But in areas that aren't currently subject to a ban on transporting unsecured dogs by pickup, the legislation's supporters point to its potential to save lives.

"I treat my dog like it's my kid," Nuckles said. "I would never put my children back there without restraints or a seat or something like that, so I think they need restraints, at the least."