How to estimate cars speed with video from rear view camera

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Hi! I've been doing a project. and I need to estimate the speed of cars that comes from the back. So, I'll use the camera and set the camera on the top or on beneath the car. but, I've found only the car speed estimation demo from top view video like this link "https://www.youtube.com/watch?

I want to estimate car speed from like this video "https://www.youtube.com/watch?v=z9Ybb...". but, differently, I'll estimate the speed of cars in the condition that is not in driving but stopped and not night vision.
I'll estimate the speed of cars in the condition that the speed of the car is almost zero and other cars are following from the back. like this link "https://www.youtube.com/watch?v=z9Ybb..." in time range 0:55-1:00

I'll detect car using YOLOv3 and I need the way to estimate car speed using the rearview video.

Could anyone advise me about this topic? please give me some advice or recommend the Github link or papers!