It's not really possible to tell if someone saying "50% faster" means a 50% speed increase or a 50% time decrease. Even in other contexts it can be ambiguous.

It's not really possible to tell if someone saying "50% faster" means a 50% speed increase or a 50% time decrease. Even in other contexts it can be ambiguous. Yesterday I drove 60mph, today I drove 50% faster. Yesterday I got there in 1 hour, today I got there 50% faster. It's not really possible to tell them apart without looking at the numbers.