Final answer:
A soft shoulder sign in road traffic indicates that the shoulder of the road is unstable or weak and should not be used for driving or parking vehicles.
Step-by-step explanation:
In road traffic, a soft shoulder sign indicates that the shoulder of the road is unstable or weak and should not be used for driving or parking vehicles. This sign is usually placed where the pavement is not as solid as the rest of the road, such as gravel, sand, or mud.