This is the old London road from Oxford at the top of Shotover Hill. The first coach started out on the route in 1669. Passengers had to get out of laden stagecoaches and walk up the steep Shotover hill to spare the horses.
Highwaymen were rampant on this route outside Oxford in the 18th Century.
https://www.headington.org.uk/history/misc/roads_to_london.htm