Spare tire
A spare tire (also called spare wheel) is an additional wheel with a tire for a motor vehicle. It is intended as a replacement for a car tire wh…
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Slope
A slope or grade of a road refers to the tangent of the angle of the road to the horizontal. It is a special case of the slope, where zero indic…
Slippery road
Road slipperiness is a condition of low skid resistance due to insufficient road friction. It is a result of snow, ice, water, loose material an…
Siren
A siren is a sound signal that priority vehicles use to warn other road users that they have to pass.
School-area
A school environment is a place near a school. Pay extra attention to children playing.
