Chicago's wagons had hard interiors and no seat belts, just like Philadelphia's. And, as in Philadelphia, passengers tossed around during rough rides had suffered serious injuries, even paralysis.
The American Civil Liberties Union sued Chicago in 1982, contending that the wagons were inherently unsafe and that police intentionally punished passengers with "green-light rides" or "joy rides" that sent them flying off their seats, bouncing off walls, or rolling around on the floor.
The lead plaintiff was Freddie Franklin, who was severely injured in a wagon after being arrested for disorderly conduct in June 1980.
"The guy lost his lips skidding across the metal floor," said Harvey Grossman, legal director of the Chicago ACLU. "The vehicles were being used as an intentional instrument of torture. It was no different than a billy club."
The ACLU persuaded a judge to certify the case as a class action on behalf of Franklin and anyone else who had been or would be transported in a Chicago police wagon. That significantly raised the financial stakes for the city.
In May 1985, Chicago settled the suit with a $125,000 payment to Franklin and a promise to replace its wagons with safer models.
The Police Department studied the issue for six years before settling on a new model with restraint bars similar to those on amusement-park rides.
The safer wagons were phased in at a rate of 10 a year. It took until 1996 to get all the old ones off the street.
Chicago's new fleet of 50 GMC passenger vans cost $2.5 million.
But most suspects will never see the inside of those wagons. The city now uses patrol cars to transport most prisoners, reserving the wagons for unruly prisoners or mass arrests.
"Offenders are now transported in a safe environment, and injuries have diminished," said Sgt. Robert Cargie, a Chicago police spokesman.
After several years of study, Philadelphia began putting safer wagons on the street in December - at a rate of 10 per year.
City officials now say they will speed the process so that the entire 86-wagon fleet will have seat belts, padding and other safety features by 2003.
Philadelphia Police Lt. Eugene Cummings, of the department's patrol bureau, said the changes should bring an end to wagon injuries.
"Up until now, when we didn't have the prisoners restrained, anything could happen in those wagons," he said. "And it's unfortunate."