39:4-91. a. The driver of a vehicle upon a highway shall yield the right of way to any authorized emergency vehicle when it is operated on official business, or in the exercise of the driver's profession or calling, in response to an emergency call or in the pursuit of an actual or suspected violator of the law and when an audible signal by bell, siren, exhaust whistle or other means is sounded from the authorized emergency vehicle... b. This section shall not relieve the driver of any authorized emergency vehicle from the duty to drive with due regard for the...