what is the difference between "turn right at" and "turn right on"

[Unregistered]

I am non-native english speaker. I am really confused about using "at" and "on", when I want to use it for describing and address. I want to know the difference between these two phrases "turn right at 4th Ave." and "turn right on 4th Ave."

[Anglika]

In AmE, "turn right on xx Ave" means to turn right onto xx Ave.
"Turn right at xx AVe" means that when you reach xx Ave, you turn right.

[BobK]

In AmE, "turn right on xx Ave" means to turn right onto xx Ave.
"Turn right at xx AVe" means that when you reach xx Ave, you turn right.

Another usage (American for now, but in principle it could be adopted into Br E) is 'turn right on red', where the 'on' is an adverb of time [=when the light is red]. In the UK, if we ever adopted it, we'd lose the alliteration - 'left on red'.

b