The incident occurred just before midnight about a half-mile from the Plymouth Meeting Mall, authorities said. A witness told local news that the carts fell out of the trailer, scattering cardboard boxes and parcels across the roadway.

The spill blocked traffic for a period before police officers were able to move the carts to the side of the road, where they remained for hours into Thursday morning. A tow truck was dispatched to help clear the packages, police said.

As of early Thursday, police said they had been unable to reach anyone at Amazon. It remained unclear what caused the carts to fall or where the shipment originated.

An Amazon facility sits about two miles from the spill site, according to the report.

The episode highlights the scale and speed of the e-commerce logistics network that moves through the region's suburban corridors — and the disruption that can occur when something goes wrong. For local residents, the immediate concern was traffic: West Germantown Pike is a major artery connecting Plymouth Meeting to surrounding communities, and the pre-dawn blockage rippled through the morning commute.

Police did not say whether any packages were lost, damaged, or taken. The investigation into the cause of the spill is ongoing.