Huh, here in Germany we have street signs (mostly of a "you are the priority road" 45° rotated square yellow-on-white "sunny side up egg" sign and the "you are not the priority road" down-pointing white-on-red triangle; for 3-way if the priority road isn't the straight road or the concept of straight is ambiguous, there's a supplemental sign depicting the path of the priority road) permanently on traffic lights; it's also common enough for non-major roads to have the lights turned off at night so drivers tend to be familiar with falling back to the signs when the lights are off.

In absence of priority roads there is also the "right before left" rule which means that the car coming from the right if they would conflict in time is the car that has priority. It's also always illegal to enter an intersection if you can't immediately clear it; that seems to work better when there are no green traffic lights to suggest an explicit allowance to drive, though.