- Bike, car and scooter accidents have soared.
- The number of bike, car and scooter accidents has soared.
Is it up to individuals which of these two they say?
It certainly is, and how one makes that choice is likely a question pondered by linguists - I would say. It is certainly not a conscious choice on the part of native speakers. It's automatic. However, in writing news scripts and writing in general, such choices may very well be conscious.