A driver of a motor vehicle that is obliged to use a portable warning triangle must place it:
On the shoulder at a distance of at least 80m, on the motorway and Ist class roads at least 130m behind the vehicle.
On the edge of the road so as for it to be possible for approaching drivers to see it in time and distinctly and at a distance of a minimum of 50m and on the motorway at a minimum of 100m, behind the vehicle. In built-up areas the distance can be smaller, if the circumstances require it.
At any distance on the edge of the road so as it is to be clearly visible in time for arriving drivers.