Officers attended the scene on the evening of Tuesday March 20, on the B6161, Leathley Lane, near Otley, when the man stopped to help.
He gave his coat to the motorist involved, but left before officers were able to reunite him with his jacket, which is currently in storage at Harrogate Police Station.
Now, North Yorkshire Police have turned to social media in a bid to find him, sharing a photo of the forgotten jacket on Facebook and Twitter.
If it’s yours, please contact North Yorkshire Police on 101 and select option 4.