[n4r9]

> If it was such a useful feature, why people aren't using it already?

Similar things are used. For example, in the UK some insurance companies make an offer which depends on the driver installing a speed tracker and not violating the limit.

The argument "why hasn't it been done yet" is quite weak. It takes time for things to be put into law, and the relevance of this kind of intervention increases with the number of drivers on the road.

Whenever someone claims the law can't actually change people's behaviour for the better, I instantly think of the UK's plastic bag charge law in 2015, which quickly cut usage by 86%.