NJ law requires pedestrians to use sidewalks if available. How does this law work with joggers (who are pedestrians) running in the roadway?

While separated infrastructure (like sidewalks) are safer than legal protection alone, not all roads have sidewalks, and some sidewalks may be in poor condition and unsafe to jog on. 

Drivers should approach vulnerable users of all kinds with due caution and pass safely, regardless of whether they ‘should’ be in the road or not.