In Massachusetts, if you were driving as part of your job and were injured in an auto accident, you could not sue your employer for your injuries. What you could do is file a claim for workers compensation benefits with your employer's workers compensation insurance carrier.
If, however, you are less than 50% at-fault for the car accident, then you could sue the driver(s) who caused the accident. You could therefore bring a claim, in addition to your workers compensation claim, against the person(s) who caused the accident.