Lincolnshire Police was called to a collision involving one vehicle on Spalding Road, to the east of Bourne at 10.20 on Saturday 14 December.
A spokesperson said:
‘Officers found a white DAF van had left the road and had come to rest in a ditch.
‘The driver, a man in his 50s sadly died at the scene of the collision. No-one else was in the vehicle.
‘We are appealing for anyone who was in the area at the time or who saw the white van shortly before the collision driving in the area.
‘Please check any dashcam or other recorded footage and get in touch if believe you have captured the white DAF van.
‘We would also like to hear from anyone who witnessed the incident and has not yet contacted the police.
‘Anyone who has any information at all that will assist with our investigation is asked to contact the Investigating Officer by email at SCIUInvestigators@lincs.police.uk or call and leave a message on 01522 212316.’