Four people were injured when a taxi collided with an SUV, sending both vehicles careening into construction scaffolding, authorities said.

The cabbie was traveling north on First Avenue when it crashed into a black SUV heading west on 42nd Street at just before 3 p.m., fire department officials said.

Both cars then went sailing into the scaffolding on the northwest corner of the intersection, causing the structure to collapse.

Four people suffered serious injuries, and were transported to area hospitals.

The investigation is still ongoing.