The truck was on the northbound side of the highway when it overturned into the median just north of the Route 34 interchange, said Charles Webster, a spokesman with the Monmouth County Prosecutor's Office.
COLTS NECK -- Two people died and another person was hospitalized Wednesday morning after a commercial line-striping truck overturned on Route 18, authorities said.
The truck was on the northbound side of the highway when it overturned into the median just north of the Route 34 interchange in Colts Neck, said Charles Webster, a spokesman with the Monmouth County Prosecutor's Office.
The three occupants of the truck were ejected from the vehicle, Webster said.
Two were pronounced dead at the scene at around 8:30 a.m. A third occupant was taken to an area hospital. His condition is unknown as of Wednesday morning, Webster said.
As of 10 a.m., all lanes on the northbound side of the highway were closed to traffic. Traffic was detoured off exit 19A in Colts Neck, which caused delays on Route 34.
PREVIOUS: Serious crash shuts down Route 18 in Colts Neck Wednesday morning
Webster said motorists in the area should plan alternate routes and expect Route 18 to be closed for a "significant period of time."
At around 7:30 a.m., traffic was at a complete standstill for miles on the northbound side of 18, south of the accident. Motorists exited their vehicles and talked to one another.
The Monmouth County Prosecutor's Office, Serious Collision Analysis Response Team (SCART) and the Colts Neck Police Department are handling the investigation.
Officers from Marlboro and Tinton Falls assisted in controlling traffic near the crash.
Authorities asked anyone with information to contact Detective Eric Kerecman of the Monmouth County Prosecutor's Office at 1-800-533-7443 or Sgt. Kristian DeVito of the Colts Neck Police Department at 732-780-7323.
Alex Napoliello may be reached at anapoliello@njadvancemedia.com. Follow him on Twitter @alexnapoNJ. Find NJ.com on Facebook.