Lincolnshire Police were called to the collision at just before 7pm and the women were treated for their injuries, but have passed away. Their next of kin are aware.
Other emergency services attended the scene, and the road was closed off into the early hours of Saturday while officers dealt with the collision.
A police spokesman said: “We are now appealing for anyone who saw the collision or has dash cam footage to come forward.
“If you witnessed the incident or know anything that might help us in our investigations, please get in touch.”
Anyone with any information should call Lincolnshire Police on 101 quoting incident 402 of June 17, or emailing [email protected]
If you wish to remain anonymous, you can report via CrimeStoppers on 0800 555 111.