if you are the driver of a car, you can see a white circle on the position of other players.
it depends a little on the angle, but its there pretty persistant. It looks like the Arma Peripheral Dots.

video example:
https://www.youtube.com/watch?v=zSdVdOTuD30&feature=youtu.be

not sure if they are supposed to be in, but probably should not be visible through houses/walls. it also works on a plain field up to ca. 300 meters.