A pedestrian in his 60s who was found critically injured on an Essex country lane was not hit by a car as first thought, police said.
Initially it was believed that the man was injured on Wednesday after possibly being struck by a car that failed to stop.
However officers have since discovered he had collapsed.
The man was found lying unconscious in Brays Lane, Rochford, by a motorist and taken to Southend Hospital.
Insp Dick Thomas said: "The man was incredibly lucky to have survived because he fell into a busy road with no footpath.
"It was foggy and he could easily have been run over by any vehicle that came around the bend and failed to see him.
"He was lucky that a woman driving a red Vauxhall Astra stopped and raised the alarm.
"We want to hear from the driver of the Astra or anyone who saw what happened to cause the man to collapse at the roadside."