Three people were injured this morning when a car hit a horse carriage on Independence Mall and triggered a chain-reaction crash involving two other horse-drawn coaches, police said.

No horses were seriously hurt, police said, although they broke free on impact and had to be rounded up after the 10 a.m. accident.

Two carriage drivers were taken to Jefferson Hospital in serious but stable condition, police said. The driver of the car was taken to Hahnemann University Hospital.

Police said the three carriages were stopped at the red light on North Sixth Street at Race when a black car driven by an elderly man slammed into the rear coach, pushing it across Arch Street into a fence and knocking aside the other carriages.

The horses broke free because their harnesses are designed to release them if the carriage is hit.

The accident backed up traffic in the area for almost two hours and prompted police to close the exit ramp from I-676 to Sixth Street, a main feeder to the Ben Franklin Bridge.

An investigation is under way.