Public transport investment is probably a more efficient investment than either and avoids subsidizing only white collar positions that tend to be high income in the first place.

The problem isn't what a segment of the population is doing it's that everyone needs a car to get around.

But buying new cars also helps the economy

If the goal is reduction of carbon and environmental impact, building lots of new cars from newly mined materials is a bit silly.

There are often multiple goals. My guess is the reason why something like this is picked over something carbon negative is because of the economy. You can downvote it but it's $462 billion into car companies and all their subsidiaries, which is something that tends to have broad public support.