Abby Hucknall, 18, and Jane MacDonald, 37, died after they were hit by a Land Rover while crossing a busy stretch of road near a supermarket in Kirkcaldy, Fife.
The two victims were pronounced dead at the scene and a police investigation was still ongoing yesterday into the cause of the crash.
Sam Clark, 35, a community staff nurse, was in a line of traffic behind the Land Rover and rushed to help the two women.
She said: "I didn't actually see the impact so I can't say exactly what happened, but I heard a bump and the Land Rover stopped.
"I could see that there were people hurt so I got out to help.
"A few other people and myself did everything we could to help them until the ambulance arrived. The paramedics were still working on them when they were taken away."
Ms Clark added: "It's so sad, I really feel for their families. I came back today to put some flowers down. There have been a few fatalities on this road over the years. Something really needs to be done.
"It's a 40mph limit along here and the impact of that compared to 30mph, as everybody knows, is much higher."
The accident happened at around 6.30pm on Tuesday on a busy road next to an Asda supermarket. The road was closed until yesterday afternoon.
The man driving the Land Rover was uninjured.
The family of Ms MacDonald were too distressed to comment yesterday but the family of Ms Hucknall paid tribute to the teenager in a statement.
It read: "Abby's family are devastated by this tragic loss. She was a very bubbly, caring and beautiful girl, a much-loved daughter, sister and grand-daughter who will be sorely missed by all who knew her."
In 2004, 10-year-old Gordon Logan was killed crossing the road after visiting his mother Wendy at work in Asda. The driver who knocked him down was doing 86mph.
Ms Logan, 41, from Kirkcaldy, said yesterday: "The accident has brought back a lot of bad memories for me and my family.
"It's devastating for the families involved in this and they'll never be the same again.
"It shouldn't have happened. This road has claimed so many victims. My son was killed, a lady was killed a few years ago and now these two ladies have died.
"The road should be reduced to a 30mph speed limit. There's so much traffic and there are so many pedestrians because of the supermarket."
A Fife Constabulary spokesman said: "Inquiries are continuing in the area and police would ask anyone with any information about this incident to call us."
l A male pedestrian died at the scene after being hit by a Volkswagen van on a country road on Deeside, Aberdeenshire.
Police want to speak to anyone who witnessed the accident, at about 7.20pm last night on the B9077 South Deeside Road at Wester Durris, near Banchory.