2005 Commercial Driver’s License Manual lanes when approaching a roadside incident or emergency vehicle. Signs are posted on roadways instates that have such laws. When approaching an authorized emergency vehicle stopped on the roadside or a work zone, you should proceed with caution by slowing and yielding the right-of-way by making a lane change into a lane not next to that of the authorized emergency vehicle or work zone if safety and traffic conditions permit. If a lane change is unsafe, slowdown and proceed with caution while maintaining a safe speed for traffic conditions. Slowdown and be very careful if you see any of the following road hazards.