All privately employed flaggers at highway construction sites on public ways must have training in controlling traffic at construction sites in a manner consistent with the standards set forth in the American National Standards Institute, Manual on Uniform Traffic Control Devices for Streets and Highways. That training may consist of video instruction, instruction in a classroom setting, distribution of informational handbooks or other educational materials or other training activities determined appropriate by the employer. Municipalities are encouraged to provide the same training as is required for privately employed flaggers to flaggers whom they employ.   [PL 1991, c. 401 (NEW).]