It is never safe to drive a motorcycle on the shoulder of a freeway, even in stop-and-go traffic. The shoulder is not designed for motorized vehicles, and it is often uneven, littered with debris, and/or soft, which can cause a motorcycle to lose control. Additionally, cars and trucks may suddenly merge onto the freeway from on-ramps, and drivers may be distracted or unaware that a motorcycle is in the shoulder. If a motorcycle is struck from the rear by a car or truck, the rider is likely to be seriously injured or killed.
If you are caught in stop-and-go traffic on a freeway, it is best to stay in your lane and wait for it to clear up. If you need to get off the freeway, use an off-ramp rather than the shoulder.