McKenna was charged with driving while intoxicated following a May 13, 2013 accident on the Garden State Parkway near mile-marker 108 in Tinton Falls.
"The investigation indicated that McKenna was traveling north in the express lanes of the parkway when he lost control of his vehicle (a Mercedes), striking the right guardrail. After the vehicle struck the guardrail, it spun, facing oncoming traffic," Sgt. Brian Polite said following the May incident.
McKenna was mayor of Red Bank from 1991 to 2006.
This article contains earlier reporting by Elaine Van Develde.