Crash closes US-1 southbound at mainland connector, later cleared

A crash on the mainland side of U.S. 1 briefly cut southbound traffic to the Florida Keys, shutting all lanes at mile marker 119 and creating a backup on the corridor Monroe County relies on for nearly every trip in and out of the islands.

The shutdown hit the stretch of road that links Monroe County and Miami-Dade County, where U.S. 1 serves as the Keys’ only direct highway connection to South Florida. Traffic on the southbound side came to a halt Sunday afternoon after the crash, and the closure rippled quickly through the 18 Mile Stretch, where even a short interruption can stall commuters, visitors, deliveries and emergency travel.

Traffic systems later showed the crash had been cleared and the lanes reopened. The incident was listed as a southbound U.S. 1 crash at mile marker 119 on the mainland, and the traffic alert described it as a routine roadway incident that was being updated in real time as conditions changed.

FL511, Florida’s official traffic and incident information system, carried the alert and provides up-to-the-minute traffic details, including accident reports, travel times and camera views. Florida Highway Patrol crash and road-condition reports are updated every five minutes, which is why closures on the U.S. 1 connector can appear and clear quickly as responders assess the scene and reopen the roadway.

A local report said the crash happened shortly before noon and led to a miles-long backup along the 18 Mile Stretch between Florida City and Key Largo. That corridor is one of the most important transportation choke points in Monroe County, and any disruption there can cascade across the Keys, especially on weekends when traffic volumes rise and travelers are moving between the mainland and island communities.

Miami-Dade Fire Rescue was among the agencies tied to the response area, underscoring how incidents at the Monroe County-Miami-Dade County line often require coordination across jurisdictions. Even when the closure lasts only a short time, the impact can be immediate: traffic stacks up, travel times climb and the entire Keys connection slows to a crawl until the roadway is fully reopened.