Streamlined Greta Green 87 years old

In the world of this cartoon, cars act like humans. Junior wants to grow up to be a taxi, but mom wants him to be a nice, respectable touring car (taxi dancers are literally taxis). What mom doesn't know is that junior has been sneaking into town to play in traffic, drink hi-test gas, and race trains. He runs out of gas at a particularly bad time and gets towed to the garage.