PC Rosie Prior and man die after lorry hits them at North Yorkshire A19 crash site
Ms Prior joined the force as a student officer in May 2022.
Her family described her as "a loving mum, wife, daughter, sister, aunty and will be deeply missed".
Mr Welford's family said he was a "hard-working and loving father, husband, son and brother".
"He will be greatly missed by his family and friends," they said.
Ms Prior had joined North Yorkshire Police more than two years ago because "she wanted to help people," Mr Forber said.
"Rosie epitomises the very best of British policing, she put the safety of others before her own safety," he said.
"Yesterday morning, she wasn't on duty on a shift, she was off duty, and she came across the road traffic collision on the A19 and she stopped to help.
"She got out and like many police officers up and down the country put herself on duty."
He said his thoughts were with the family of Mr Welford and that it was a "deeply traumatic and heart-breaking event for everyone involved".
Home Secretary, Yvette Cooper, said the deaths of Ms Prior and Mr Welford were a "profound tragedy".
"This brave officer's passing serves as a reminder of the risks that our dedicated police officers face every single day in the line of duty," she said.