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Just for counting? For speed also?
(lemmy.world)
Yeah I know these are used for counting vehicles but can they also be used for detecting vehicle speed?
Description: two pneumatic hoses, affixed to a road. They lead to a box that's locked to a telephone pole. Location is southern California. On a minor artery road.
Doubtful that it's to survey if a new stop sign is needed since the next street is minor, dead ends into this one and already has a stop sign. The next intersection with another minor artery already has a stop sign.
Extremely doubtful that a traffic light is being considered since there isn't anywhere near the amount of traffic to justify one.
This is located on a slope. Many cars speed down here. That's why I'm wondering about speed sensing by this device.
They are for counting vehicles. You cannot determine speed accurately without knowing the tire circumference
The circumference? Why would that matter? You have distance between the detectors and you have the time between their triggering. That's enough to get a good estimation of the speed and direction of the triggering vehicles.
Yeah I mixed up the knowledge of how wheel size impacts speedometer accuracy with this
Whoops
By that logic, you cannot tell how fast I'm walking without my circumference.
If you know the distance between the two tubes you could determine speed and not need to know anything about the tire.
Would they be able to account for the difference in length between each axle on different vehicles?
First hit on each would be the same tire and that’s all the information needed.
That makes sense
You measure a single tire, the whole vehicle doesn’t matter.
How does the circumference matter?
It does not. Circumference only tells you speed if you're measuring tire rotations, which this is not.