The road is a few meters distance spike installation a
1.5 meters to 5 meters distance can be accepted, according to their actual point of view. If there is a design unit indicators, according to the design plan to do! We are also selling this piece, not listening to engineering units have this question
In principle, the speed is fast and the distance can be relatively large! Mainly to consider the visual effects of driving!
This shouldn't be a special requirement. For example, in a parking lot, the distance is different from that on the freeway, because the speed of the car is different
