Robinson said the car caught fire after the crash, ignited nearby bush, and started a significant scrub fire.
Rawene and Kaikohe fire brigades spent more than three hours fighting the blaze.
In the other crash, a motorcyclist hit the side of a bridge on Tangowahine Valley Rd about 4pm on Saturday.
Senior Sergeant Daniel Cleaver said initial investigations showed the northbound motorcyclist, a 63-year-old man from Auckland, failed to take a moderate bend going over the bridge.
He said motorcyclists should ride to the conditions and to their ability.
"If you aren't sure of the roads, slow down a wee bit. That should allow you time to see ahead. Both crashes occurred on a bend which indicates the motorcyclists were not sure where the road was going."