What does this identification mark mean?

Explanation

The vehicle is fitted with studded tyres.

What you see is a white triangle with a red border and the letter "Ш" in the middle. This is not a roadside sign; it is a vehicle identification mark fitted to the rear window of the car. The letter "Ш" is the initial of the Russian word for a studded tyre, and that letter is the only means of recognising it.

Its safety logic goes back to the physics of braking. A studded tyre has far greater grip on ice and packed snow and shortens the stopping distance, but on dry or wet asphalt it performs worse than an ordinary tyre. That is, the braking behaviour of such a vehicle differs from what you expect of an ordinary one. A driver following it must know that on an icy road the vehicle ahead may stop far sooner than expected, and for that reason must keep a greater following distance. This mark is fitted precisely to make that behaviour predictable.

The exam trap is the triangular shape and red border, which pull you towards the group of road warning signs and make options such as "a bump in the roadway" or "three lanes" plausible. The rule for telling them apart is simple: a road sign is mounted on a post beside the road and bears a pictorial symbol; an identification mark sits on the vehicle's body and here bears a letter of the alphabet instead of a picture.

• "A bump in the roadway" has its own separate warning sign with the image of a raised hump, not a letter of the alphabet. • "Three lanes in that direction" is announced by a blue rectangular sign showing traffic lanes; no triangular sign carries such a message.

Sources and content coverage · Report a content error