The incident took place around 10:08 a.m., Wednesday, Sept. 18 at the Webster Avenue overpass in New Rochelle, said Trooper Tara McCormick.
The lanes were closed between Exits 15 and 16, McCormick said.
The person, who has not been identified, suffered extensive head injuries and was transported to an area hospital, she said.
Motorists are advised to avoid the area as police investigate the incident, she added.
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