A priority-road route bends left through an intersection, and a supplementary sign shows the priority road's path. You intend to continue straight off the priority road. What must you do?

1. Assume you keep priority because you arrived on the priority road
2. Read the supplementary sign and yield to traffic staying on the priority route if your path crosses it
3. Use the horn and proceed first
4. Apply the right-hand rule without looking at the priority-route sign