The father of a five-month-old boy killed when a van mounted the pavement and hit his pram said it was "quite miraculous" his wife survived.
Rachael Thorold, 36, was walking with her son Louis by the A10 in Waterbeach, Cambridgeshire, on 22 January when they were hit.
Louis died at the scene and his mother was left with serious injuries.
Chris Thorold said when he arrived at hospital, staff treating his wife "prepared me for the worst".
He added: "I don't think they expected her to survive the first 72 hours to be perfectly honest. That's hard. I gave myself a bit of a talking to and said, 'you've got to be strong here'.
"The fact that Rachael has survived is quite miraculous, but I guess Louis, being a little guy, just wasn't strong enough."
He said he was "prepared for everything", adding: "It sounds a bit sad but if she had not made it I kind of thought 'well at least she's with Louis'.
"Maybe there's not much solace in that and clearly, selfishly, I wanted her to survive, but I also made a little bit of peace that if things don't go well for her then at least she's with our little one."
Mr Thorold said he "can't do enough" to thank those involved in his wife's care.
She has been discharged from intensive care and was "exceeding all expectations", he said, adding she could now sit awake and talk to him.
"Clearly she has lots to do - a couple of weeks ago she didn't know what day of the week it was but now she does," he said.
He added that he hoped she would be out of hospital in the next four to six weeks.
Mr Thorold said: "It's been hard but she's just an incredible woman and, given what's happened to her and Louis, her motivation and her strength is quite admirable."
'Beautiful little boy'
Louis was born in August and Mr Thorold said he "felt so grateful we had him".
"Him and Rachael were just inseparable, never spent a moment apart," he said.
"I couldn't have asked for a happier five-and-a-half months and a more beautiful little boy - smiley, happy, always giggling away."
Mr Thorold said he tried to delay Louis's funeral for as long as possible "to see if Rachael was going to get better and there was any chance she could come".
He said it became apparent in early February that was not a realistic prospect, and said they "gave him a lovely funeral", with support from the "fantastic" local community.
"His funeral, without a doubt, was the hardest day I've ever encountered. Let's just hope he's gone to a better place," said Mr Thorold.
'His life needs to mean something'
He set up the Louis Thorold Foundation with the aim of eliminating infant pedestrian deaths, and called for immediate improvements at the junction of the A10 and Car Dyke Road.
Mr Thorold said: "I don't know if there's a textbook on how to grieve. I guess my way of dealing with it is, yes it's sad but his life needs to mean something.
"With his plight and what he's been through, hopefully we can do something with it and prevent this happening to anyone else."
He said there were "way too many stories of little ones not making it home and all of it is preventable".
"The technology, systems, and approaches to prevent every single one of these deaths exists.
"I think if we can prevent one more child dying on the roads in Britain... then Louis has done something good for his friends."
Mr Thorold has met with Cambridgeshire County Council and it said it had brought forward a route safety study of the A10 and was working to start the construction of a path for walkers and cyclists.
Cambridgeshire Police said an investigation was ongoing.