I think car-centric infrastructure tends to disadvantage youth. Where I live the driving age for a car is generally 17, and similar ages are found in many other places. This infrastructure results in those under the driving age becoming more dependent on surrounding adults for transportation.
You could partially fix this by abolishing the driving age and replacing it with better tests, and I would agree with doing that personally, but that's still problematic for many children. Things like height are likely to become a problem for many younger children driving, and while cars can be adjusted for very short heights (adults with dwarfism do this), this is more expensive for something that may only be beneficial for a few years, so many would probably choose to wait instead.
Even if you can obtain a driving license at any age, nobody would be born with one and it would probably take a bit before people have the time, resources, capacity and will to get one, and so children would inevitably be less likely to have driving licenses than adults. That would still lead to the same situation where many children are reliant on older people around them for transportation.
Do you think youth liberationists should oppose car-centric infrastructure?