I see these LED speed signs on the side of the road, which display the approaching vehicle's speed.
What I have gathered is that they measure the time between the sending and receiving of the signals and then convert it into distance. My questions are:
- How is it displayed for each vehicle on the lane which are also moving forward at the same time (like cars from left to right)?
- How effective is it if the drivers just see the number on the sign change but they are not sure of which vehicle's speed the sign is currently displaying?
I have already checked out the wiki on how radar speed signs work, but they don't explain the mechanism. I would love to know how they work in detail, and how the signs address the speed issue in countries with wide roads and high traffic like India.