Police investigating a fatal hit-and-run crash 18 months ago have released details of the type of vehicle they think was involved.
Barbara Liddle, 76, was hit by what officers now believe was a black Vauxhall Zafira on Camp Road, St Albans, on 28 September 2017.
She was found with serious injuries just after 20:20 BST and later died at the scene.
The vehicle did not stop and no arrests have been made.
Mother of two Ms Liddle was crossing the road outside her home to wait for a friend to collect her for a darts match.
Sgt James Thorne has asked the public to think back to September and October 2017 and whether friends or family members acted strangely, seemed distressed by something or had unexplained damage to the front of their vehicle.
"I would also ask those who work in garages and car repair workshops to think about whether they repaired a black Vauxhall Zafira with front end damage around the time of the collision," he said.
"My team have shown great dedication to investigating this collision, but we are still missing a vital piece of the puzzle.
"The driver of the Vauxhall is out there somewhere. If they are reading this, I would urge them to think of Barbara's family and hand themselves in. Please, do the right thing."
Kevin Donaghey-Liddle, Ms Liddle's son, said: "It doesn't make sense to any of us how the driver of that car can go on knowing they have destroyed the lives of others.
"There are some truly messed up people out there, but if there's any justice in the world he or she will come forward and put an end to our grief and at least give us some closure."
Ms Liddle's daughter, Sharon Liddle, said: "They have shown no regard for her or us, and they've stayed away knowing what they did."