The award comes just two days after the mother of the children, Mary McCann, was jailed for more than four years for causing their deaths through careless driving.
Proceedings in the case had been delayed when McCann failed to appear at court last year, she eventually handed herself in at Aylesbury Police station on 16 September.
The court heard she was speeding and was over the legal limit for alcohol.
PC Matt Diduca and PC Colin Riley were the road policing officers sent to the crash and this week police revealed the incredible efforts they made to save little Lily, aged four, and her 10-year-old brother called Smaller.
A Thames Valley Police spokesman said: “Information came through quickly that the collision was very serious and involved young children.
"But as the officers reached the tailback to the M1 they were stopped by four lanes of stationary traffic and no hard shoulder, due to a smart motorway being constructed."
PC Diduca got out of the car and ran several miles to the scene, with no kit.
"When he arrived at the scene, he was faced with one child who had been ejected from the vehicle suffering non-survivable injuries, and another young child who was in cardiac arrest,” said the spokesman.
Firefighters performed CPR, but tragically the two children died at the scene.
"The driver of the car was the mother of the children and was understandably distraught.
"PC Diduca recognised that she smelt of alcohol, meaning she was also a suspect.
"He took control of the situation and began to complete the scene assessment under incredible stress,” said the spokesman.
Meanwhile PC Riley eventually managed to obtain ambulance equipment and he ran down the hard shoulder to join PC Diduca.
Both officers managed to build a rapport with the mother, securing her co-operation, said the spokesman.PC Diduca said: “When I arrived at the crash it was a scene of devastation.
"I was trying to help the fire crew save the children, but I was also mindful that this was potentially a crime scene and I had to do my job.
"Also the mother was intoxicated and was trying to end her own life.”He added: “The enormity of the job doesn’t dawn on you until afterwards. It was very hard to keep my emotions in check. I feel humble to have won this Award, although any officer would have done the same.”PC Riley said: “It was harrowing, but we had to stay professional.
"The mother was over the drink drive limit, but we treated her with compassion, because she’d just lost two of her children. We sat with her and tried to calm her down, and we knew we had to get a sample of breath or blood from her.”
Both officers will receive an Excellence in Policing Award at the TVP Federation Bravery Awards on Thursday.
PC Riley admitted: “I have mixed emotions about winning this Award – it’s part of our job, it’s what we deal with week in, week out. It’s nice to be recognised, but it’s under very sad circumstances.”