Accidents can occur to horses in harness. It's amazing, when you look at how little room they have going through those hazards, with the width of the vehicle. In any driving situation, the horse might catch his bridle on an object and pull it off, so the driver loses all control. The horse also could get a leg over a shaft and panic before a helper can release him from the predicament. Working in winter, the horse can get snow balled up in his feet and lose his footing.
Drivers try to avoid such crises, but adding multiple horses increases problems.
To untangle the animals, officials stopped the show while handlers unhitched all four horses. Lameness in driving horses varies according to their work. Becker observes fewer navicular problems, but more road founder. Moore noted he sees fewer hock problems in driving horses. The pounding is worse in dressage and hunter-jumper horses.