How are the ducks still on the road? For that matter, how did they get on the road in the first place? That’s what Karen Koehler wants to know. “They’re military vehicles. Would it be okay to put tanks on the street if we could hook tourists into them somehow?”

Koehler is the attorney for 20 victims of the second-deadliest duck-related accident in U.S. history. Maybe you remember it: At a little after 11am on September 24, 2015, a Ride the Ducks vehicle traveling north on the Aurora Bridge swerved violently across the center line and slammed into the side of a southbound charter bus carrying international students from North Seattle College. Without safety belts to keep them in their seats or windows to keep them in the vehicle, the duck’s passengers were thrown to the pavement. But the bus riders fared much worse: Five died—four of them at the scene—and dozens more were injured.

“I represent a lot of people who have suffered terribly,” Koehler says. “When they see those vehicles, all they see is death.”

For nearly 20 years the repurposed WWII amphibious transports named for an impossibly convoluted manufacturer acronym have quacked their way through downtown and into Lake Union, ferrying—by the company’s count—300,000 passengers annually on sightseeing excursions set to all the songs you wish you could forget from the ’70s, ’80s, and ’90s. And it’s a lucrative enterprise: Ride the Ducks Seattle raked in $9.6 million in 2014.

It’s also one of the most closely scrutinized operators of commercial passenger vehicles in the state: Even before the wreck, the U.S. Coast Guard subjected the ducks to twice-annual float tests and ensured that their hulls were sealed properly. The Washington Utilities and Transportation Commission inspects the vehicles’ roadworthiness every two years and makes sure the company follows state-mandated drug and alcohol testing procedures. The feds are even available to double-check the state’s work if needed.

And Ride the Ducks routinely receives satisfactory safety reviews from those agencies. As company spokesperson Mark Firmani proudly points out, Seattle’s ducks are involved in almost 75 percent fewer preventable accidents per million miles than Metro buses. “Let’s be absolutely clear,” he says. “Prior to [the Aurora Bridge crash] Ride the Ducks of Seattle operated 19 years without a single fatality.”

Yet when the National Transportation Safety Board released its preliminary report on the September accident, it found that the company had failed to address a known problem with the axles on its larger stretch ducks—the very problem that caused the vehicle to veer into oncoming traffic. And after conducting its own close review of Ride the Ducks’ operations, the Utilities and Transportation Commission found more than 400 safety violations.

“Would it be okay to put tanks on the street if we could hook tourists into them?”

So how exactly can a company that boasts such a clean record fail so catastrophically to protect its passengers and others on the road? Dave Pratt, the UTC’s assistant director of transportation safety says Ride the Ducks was a victim of its own success. “They grew really fast,” he says. “They expanded the size of their fleet, and the record keeping and safety got lost.”

Chad Wiesenfeld thinks it’s something else. For three years, from 2007 to 2010, he was a Ride the Ducks captain. And although he’s never made more money than he did while carting tourists around town and cracking bad jokes—as much as $400 a day—you’d have a hard time getting him back behind the wheel now. “They’ll always be the most dangerous vehicle in Seattle,” Wiesenfeld says. “I do not think they can be operated on city streets safely.”

Two of his biggest complaints dealt with visibility and distractions. A duck operator sits nearly 10 feet from the vehicle’s bow, making it nearly impossible to see people and cars directly in front of it. (Compare that to city buses and garbage trucks, which place the driver as far forward as physically possible.) Wiesenfeld says he once rear-ended a car that he didn’t even know was in front of him while trying to turn right at a downtown intersection.

Then there were all of the other responsibilities he had in addition to driving: narrating the tour, changing the music, changing his wigs. “There were times when I had to operate the steering wheel with my knees because my hands had so much else to do,” he says.

In the six years since he left, both problems have been addressed—in response to severe accidents. Ride the Ducks added cameras to the bow after a driver ran over a motorcyclist at Third and Pike in October 2011. And the Aurora Bridge crash prompted the company to add a dedicated entertainer to every tour, allowing the driver to focus on, yes, driving. But there’s one hazard the ducks will never be able to eliminate.

Like Metro buses, ducks are eight and a half feet wide—the maximum allowed on Washington streets. They’re shorter than buses by several feet. And yet somehow—maybe it’s the music, maybe it’s that they represent the intrusion of outsiders that so many Seattleites resent—ducks seem bigger. Even Dave Pratt of the UTC was surprised to find they’re no larger than anything else on the road: “I wouldn’t have guessed they’re smaller than garbage trucks.”

And that misperception breeds a contempt that Wiesenfeld saw firsthand. Other drivers, particularly at rush hour, would speed up to pass him, cut him off, or turn corners in front of him. The duck wasn’t another vehicle to share the road with; it was an obstruction.

Since last September, Ride the Ducks has complied fully with the NTSB and the UTC. And after a UTC-mandated suspension in the wake of the accident, the company was allowed to relaunch half of its 20-vehicle fleet in January. There’s no timetable for when the rest will return. The bigger question, though, is whether Seattle drivers will welcome them back.