She was driving on Kinnelon Road in Kinnelon, New Jersey at 8:40 Sunday morning when the road collapsed because of rushing water caused by Irene.
The 39-year-old woman escaped from her GMC Yukon and got a ride from another motorist.
Police arrived and, fearing she had been washed away, searched for 90 minutes before the driver arrived at police headquarters to report the incident.
She was not hurt.
The collapse is expected to close Kinnelon Road for three months.