Lincolnshire Police were called to the road, between High Ferry Lane and Willows Lane, Sibsey, at around 12.22am on Sunday 27 November.
A white van had hit a pedestrian in his 40s from the Boston area who later died.
Two people – a woman, aged 39, and a man, aged 33 – have been arrested on suspicion of causing death by dangerous driving.
Police said the road is due to be closed until at least mid-morning on Monday 28 September while officers continue to investigate the crash.
They are appealing for witnesses or anyone with dashcam footage of what happened.