A "number of lines of inquiry" are being pursued by police investigating a fatal hit-and-run crash a year ago.
On 28 September 2017, Barbara Liddle, 76, was hit by a vehicle on Camp Road, St Albans, while waiting for a friend to collect her for a darts match.
She was found with "serious injuries" just after 20:20 BST, but later died at the scene. The vehicle did not stop.
No arrests have been made but police say they are continuing with their investigation.
PC Jackie Lister, from Hertfordshire Police, said: "Somewhere out there is the person who did this, and for the past year they have carried on living their lives.
"Meanwhile, Barbara's family have had to cope with the devastating consequences of that person's actions after they chose to leave the scene."
She asked the person responsible to "do the right thing" and hand themselves in.
"We also appeal to others to think back to this time last year. Did a member of your family or one of your friends start acting strangely? Did they have damage to the front of their vehicle that they couldn't explain?" PC Lister said.
"I want to reassure Barbara's family that we are still following a number of lines of inquiry and will continue to do so until all of these have been exhausted."
Ms Liddle's daughter, Sharon Liddle, said: "The past year without Mum has been dreadful. I've tried to take it one day at a time, but it's been really difficult. I miss her so much.
"Mum and I used to see each other every day and on a Monday we used to go shopping. We were very close."
Kevin Donaghey-Liddle, Ms Liddle's son, said: "Mum was always a shoulder to lean on. She supported us throughout our lives and is truly missed.
"This is a time of great sadness for us all and we urge anyone with information to come forward."