The two riders, Hoogerland with the Vacansoleil-DCM team and Spaniard Juan Antonio Flecha with Sky, were in the lead some 37 kilometers from the finish line in Saint-Flour when a car clipped Flecha, sending him sprawling.
Hoogerland then collided with Flecha and went flying through the air into a neighbouring field where he landed on a barbed-wire fence. He suffered lacerations to his leg and was "covered with blood," according to his team's directors.
Flecha was able to get back on his bike and rejoin the race. Hoogerland had his legs and knees bandaged before setting off again.
The accident deprived Hoogerland of a possible victory. He ended up finishing the day in 139th place, but was awarded the polka-dot jersey as the best climber of the stage.
"I'm not angry, as I don't think it was anyone's fault. I'm still alive," he told journalists.
France Télévisions issued an apology for the incident.
The Tour de France administration said that the car in question was not following the proper guidelines when the accident occurred.
The crash was the second such incident in recent days. On Wednesday, a photographer's motorcycle caused a rider with the Saxo Bank team, Nicki Sorenson from Denmark, to take a tumble.
"It's a scandal," said Christian Prudhomme, the Tour de France director. "Two accidents linked to the media in just a few days during the Tour de France are two accidents too many."