An employer can have the best trained individual driving his forklift and that individual can be having a bad day. A fight with his spouse, short night of sleep, or thinking of the coming weekend can distract someone from the safety of day to day work.
There is a product on the market called SpeedShield that can set maximum travel speeds based on mast lift height and weight of the load it is carrying.
SpeedShield can slow the vehicle down as it approaches a pedestrian cross walk and automatically sound the horn. It can require he has his seat belt fastened around him before he can drive the forklift. It can slow him down and sound an alarm as he approaches an overhead obsticle if his mast is too high.

Speedshield does not replace training, it reinforces safe forklift operating practices. As one of my customers says "safety is no accident!" SpeedShield is the solution.