A soft shoulder sign is a traffic warning sign. Warning signs alert you to important conditions on the road ahead. These may be road hazards, changes in direction or some other situation you need to know about. Many of the yellow diamond shaped signs are warning signs that you should slow down, especially on wet roads. Warning signs are there for your benefit, and they must be observed.
Soft shoulder signs alert you to areas where the pavement will affect your vehicle's traction. It's not safe to drive off the pavement when you see a soft shoulder sign, so make sure you stay in your lane. If you ignore a soft shoulder sign and your vehicle runs off the pavement, you're going to have a difficult time regaining traction and control of your vehicle.