Firefighters had to cut the roof off a car to free a trapped motorist whose car had plummeted into a ditch, forcing police to close the southbound A41.
Emergency services rushed to help the man after a frantic 999 call-out at about 6.35pm on Thursday evening.
His white Nissan Micra had left the carriageway about a mile after passing the McDonald’s restaurant at the Bourne End Mills Industrial Estate.
Police closed the southbound A41 at about 7.15pm and the man was taken to Watford General Hospital – but he is not thought to have been badly injured. The road was reopened just after 8.25pm.