An alert driver helped save a man stuck in a storm drain along a busy Denver highway Friday.

After hearing cries for help and seeing a hand sticking out of a grate, a driver called 911, Denver 7 reported. Emergency responders blocked off three lanes of I-25 during holiday rush hour traffic to conduct the rescue operation.

Firefighters removed the grate and lowered a ladder down to the man, who was conscious and able to communicate with the first responders. After freeing the man, paramedics took him to the hospital.

Officials told Denver 7 that the man didn't appear to be injured. Firefighters think he entered the storm drain near the South Platte River, but don't know why he was in the storm drain or how long he was down there.