In view of the safety issues you would need monitoring systems in addition to the servo driver. For example, you would need to detect if the pedal pot had gone open circuit, or short circuit or excessively high/low resistance. The servo current, operating duration and position would also require monitoring with a back-up system in case the servo pot failed.

 

Drive-by-wire is scary enough when the big auto companies design it, but it's downright horrifying on the hobby level.

 

For safety you would need a way for the brake light signal to mechanically override the servo if it goes to full throttle.