Highway Petrol

The first step is to solve the Sudoku. Basic techniques will get you most of the way through, and the highway routes will help yield a unique solution:

At this point, you might wonder what to do with the colored cells. Revisiting the flavortext, you might have noticed that some words are italicized: Piston Cup racers, last, and name. With some Googling, you’ll hopefully come across this Pixar Wiki on Piston Cup Racers. Each colored group of cells represents a Piston Cup car in the original Cars film. For instance, 95 is Lightning McQueen’s number (and you might notice that the red background and yellow sides match his colors as well). Taking the first letter of each racer's last name yields MIDDLES:

Take the middle numbers in each subgrid of the Sudoku:

Indexing these into the alphabet (A=1, B=2, etc.) yields AGEDCHIEF. By checking this against the solution checker, we’ll ask you:

Who is the AGED CHIEF in Cars who taught McQueen that friends are more important than trophies and fame? (3 6)

The answer is DOC HUDSON, the doctor and judge of Radiator Springs and former Piston Cup champion who becomes a mentor for McQueen.

We're both sudoku fans. This puzzle is a light version of Killer Sudoku with a Cars theme -- the use of highways (and their route numbers).

Figuring out extraction was a little tricker. Luckily, when we realized practically all race cars have special numbers assigned to them, dropping them into the sudoku made a lot of sense.

Of course, if those cars directly yielded the final answer, that would be too easy, so we inserted the "middles" step to have solvers revisit the sudoku to find even more hidden.

We had to think hard about the "middles" extraction, since it is constrained by the fact that we can use only the letters A-I (1-9). When we thought of AGED CHIEF, we realized this was a perfect description of Doc Hudson.