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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.
I don't know for sure, but I think theoretically you could calculate the time it takes between a tire driving over each line to determine the vehicle speed. I imagine that's why there are two lines and not just one.
For sure can do speed if you know how far apart the lines are.
Probably work if distance between front and rear axle was a standardised measurement, but since it isn’t this wouldn’t be very inaccurate.
For counting or for speed? You can't really measure speed with one because of that issue, but you easily can with two. For counting it's probably good enough to count pulses and divide by two. Sure, some trucks have more than one axle, but it might not matter. Plus I'm guessing with enough data they have a signature of what multi-axle vehicles look like.