How many meters is the tunnel sign outside?

Under normal circumstances, an intersection is set at 200-500m from the tunnel exit. Expressway is a high-grade highway, fully enclosed, and the traffic speed is the highest highway grade in China. In signboards, expressways are the same as national highways, starting with the letter "G", such as G65 Expressway.

The letters of provincial expressways begin with "S", such as S9 Expressway. The national highway and provincial highway are in white font with green background, with red stripes above the national highway and yellow stripes above the provincial highway. It should be noted that the expressways starting with the letters "G" and "S" are all closed expressways, but the sign starting with "S" indicates that this section belongs to a province and there is no other meaning.

This is a warning sign of the tunnel exit distance, which is used to indicate the distance to the tunnel exit ahead. Located in the extra-long tunnel over 3000m, one is set every 500m from the tunnel exit to the tunnel exit. This sign is usually set on the side wall of the tunnel.

Tunnel safety signs are as follows:

1. No sign: including the speed limit sign for construction vehicles, no entry sign for idle people and no smoking.

2. Warning signs: For example, beware of high-pressure signs and potholes.

3. Indicating signs: For example, you must wear a safety helmet.

4. Prompt signs: such as the location of fire extinguishers.