Merseyside Police are appealing for information following a fatal collision on the East Lancs Road in St Helens on Saturday.
A report was received shortly after 9.45am on December 22 that there had been a collision involving a blue Audi Q7 and a silver Peugeot 206 near the unction with Houghtons Lane.
The drivers of both vehicles were taken to hospital for assessment.
The 56-year-old driver of the Peugeot was treated for a head injury. He died on Sunday (December 23) from his injuries.
The driver of the Audi was treated for minor injuries and later discharged.
Specialist officers are working to establish the full circumstances and anyone with information is asked to come forward.
Roads Policing Sergeant Mike Clarey said: "We are keen to hear from any witnesses to this incident and welcome any information, including home CCTV or dashcam footage, which may assist our enquires."
Anyone with information is asked to contact Merseyside Police social media desk via Twitter @MerPolCC or Facebook Merseyside Police CC. You can also call 101 quoting incident reference 18400073899 or contact the independent charity Crimestoppers anonymously, on 0800 555 111 or via their online form at: https://crimestoppers-uk.org/give-information/give-information.