If a driver has trouble physically exiting a vehicle when asked to do so by a police officer, they could simply relay that information to the police officer. There are many drivers who are handicapped in some way.
would the police be justified in tazing him/her - disabling the pacemaker, causing a heart attack.....all because he/she refused to sign an incriminating instrument of the court by driving 32 miles an hour
A traffic ticket isn't an "incriminating instrument of the court". By signing a traffic ticket, you are simply agreeing to show up in court at the time and date specified. Many traffic tickets are dismissed by the court after the judge hears the motorist's side of the story.
......and ticket cams ?