It's pretty specific. And reasonable if you ask me.
All firearms transported into/through the State of New Jersey:
Shall be carried unloaded and contained in a closed and fastened case, gunbox, securely tied package, or locked in the trunk of the automobile in which it is being transported, and in the course of travel, shall include only such deviations as are reasonably necessary under the circumstances.
The firearm should not be directly accessible from the passenger compartment of the vehicle. If the vehicle does not have a compartment separate from the passenger compartment, the firearm and ammunition must be in a locked container other than the vehicle's glove compartment or console.
And here's a good question: why was it loaded? He wasn't working in his garage. A 'loaded' gun shouldn't be anywhere in an automobile, per nj law. He knew this.