State Police say the accident happened at around 6 p.m. Tuesday on the ramp from northbound I-287 to southbound Route 1 in Edison.
An 18-wheel box truck overturned, sliding into a school bus carrying the girls softball team from Bridgewater High School. None of the 30 girls on the bus were injured, but 20 of them were taken to St. Peter's Hospital in New Brunswick for evaluation.
Two people in the truck were taken by helicopter to Robert Wood Johnson Hospital in Bridgewater. Their conditions are unknown.
The cause of the accident is under investigation. The truck was carrying frozen seafood.
Northbound 287 was shut down for a short time as a landing zone for the helicopters.
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