A dump truck struck a New Jersey State Police car on Interstate 80, pushing it into a traffic stop and injuring two troopers and a third driver. The cause of the Thursday afternoon crash that tied up westbound traffic for hours in Warren County is still under investigation, state police announced on social media late Friday morning. The injuries are not believed to be life-threatening. State police said the first trooper stopped a Honda Accord and was speaking to the driver outside the car at mile marker 5.3, about a mile east of the exit for Routes 94 and 46 in Knowlton Township and five miles from the Pennsylvania border at the Delaware Water Gap. Another trooper was en route when their Chevrolet Caprice was struck in the rear by a Mack truck, pushing the police car onto the right shoulder and into the Accord, which in turn was pushed forward into the first trooper and the Accord's driver, state police said. The troopers and the Accord's driver were flown to Morristown Memorial Hospital. The truck's driver was not hurt, authorities said. The highway was closed and detoured during the evening rush hour during the initial investigation. Some readers reported being stuck in standstill traffic for two hours or more.