The collision occurred at around 1.20pm on Sunday on the M62 westbound just after junction 34 at Eggborough.
Police said a red Reliant Robin and a grey Volkswagen transporter collided.
The pensioner, an 84-year-old woman, was a front seat passenger in the Reliant and suffered serious injuries.
She was taken to Pinderfields Hospital before being transferred to Leeds General Infirmary.
Both vehicles were also badly damaged.
Police are appealing for information about the crash.
They are asking that anyone who saw the collision or saw the Reliant Robin travelling on the M62 or M180 around the time it occurred to contact PC Timothy Harding in the West Yorkshire Police Safer Roads team on 101, quoting log number 662 of Sunday, January 15.
Information can also be passed on to charity Crimestoppers anonymously on 0800 555 111.