Doc Hudson, formerly known as "The Hudson Hornet", is the doctor and judge in Radiator Springs from the movie Cars and the voicer was deceased before Cars 2. He was voiced in the movie by Paul Newman. In World of Cars, he was found driving around Willys Butte or near Twistin Tailfin Trails. He is the only deceased Cars character to appear in World Of Cars Online. He is also seen in Radiator Springs Racers.
The actor who voiced Doc Hudson in the first movie, Paul Newman, passed away. He is absent in the second movie, but was mentioned to have died. The Piston Cup was renamed after him in memory of him; the new logo was also put on Lightning's hood in his new paint job for the World Grand Prix. Doc’s office was converted into the Hudson Hornet Racing Museum, where pictures of him were shown.
When Lightning was showing Mater his new Piston Cup, they were talking about him.
Also, during the race in Tokyo, Darrell Cartrip mentioned that McQueen's mentor, the Hudson Hornet, was one of the best dirt track racers in history.
In the first race of the World Grand Prix in Tokyo, when the racers headed into the dirt section, Francesco Bernoulli was currently in the lead but having a hard time. "Get on the outside, and show em' what Doc done taught ya!" is what Mater told Lightning to do, a reference to an event that happened in the first movie. Lightning listened and beat Francesco by drifting. Interestingly, it seems that Francesco is terrible on dirt, most likely because he is a single seater-a form of car not meant for the off-road, as Raoul ÇaRoule passed him by drifting too, followed by Max Schnell and Nigel Gearsley. Eventually, he ended up in last place once he got out of the dirt section, but eventually caught up.
It is unknown how Doc died, but his legacy lives on through Lightning and the other residents of Radiator Springs, as well as the trophies he earned from his own career.
Doc didn't really appear in the World of Cars Online anymore, either. It seemed like they wanted the World of Cars Online to have the same changes that happened in the second movie. Doc no longer raced at Carburetor County Speedway or Willy's Butte Rally. In Carburetor County Speedway, he was replaced by Sally, and in Willy's Butte Rally, he was replaced by Sarge.