Is it legal to drive motorized wheelchairs in the street like a car?

I've been wondering about this because several people in my community use the motorized wheelchairs and drive them like cars, right into busy traffic. They even get out on the road at night and it is very difficult to see them and avoid crashing into them. Should they be reported to the traffic cops? I've considered offering one lady that I see daily (and worry about!) a bus pass to use for our wheelchair accessible city bus service. Your advice would be appreciated.