Traffic controllers employed by an employer are the responsibility of the employer, as with any other job. The employer will therefore be held liable in the event of incidents.
However, one exception is possible: if the employee consciously carries out actions that are in conflict with the applicable laws and regulations and the agreements between him and the employer. At that point, the employee can be held personally liable.
Drivers on the road are obliged to follow the directions of the traffic controller (except for the above exception). If an accident occurs where it is proven that the traffic controller has deliberately acted incorrectly, he can be held liable. In all other cases, the driver will have to make an assessment himself whether driving, turning, stopping, etc. poses no danger at that time.