He may be driving a grey Land Rover Defender, registration PK62 ORA.
Police are continuing to search for him, particularly in the North York Moors to the east of Northallerton.
Due to the remote, rural location, officers have deployed drones and are using off-road police bikes to cover the area.
Inspector Phoebe Southall, of North Yorkshire Police, said: “We are extremely concerned for Gerrard’s welfare, and extensive police searches are continuing today.
"I would urge anyone who may have seen him or his grey Land Rover Defender – particularly east of the River Rye and Hawnby Hill Crag area – to get in touch.