This is a big peeve for me. I think journalists are responsible for the misuse of "exponential". They use it to mean "grows very fast", while making them look erudite.

It annoys me, because science journalists are reporting on the spread of a pandemic, which absent controlling factors actually does grow exponentially. So having degraded the term, they now lack a word to describe a quantity whose rate of growth is proportional to its magnitude.

In that case I'd assume the meaning is related to the exponential growth in towable tonnage compared to the size or weight of the car.