I know all of you have seen these at least once on the road. They resemble bungy cords stretched across the road surface and connected to a small box on the side of the road, only temporary and usually in pairs, about a foot separating them. Does anyone know what the purpose of these are. My guess is its used to count vehicle traffic. Does anyone know for sure???
I think there was a 100000 page thread about this here at one time. It was a debate between the engineers of NYSpeed and the “engineers” of NYSpeed as to if they were placed to record speeds or traffic…
I’m pretty sure it’s to count traffic.
it is a traffic counter. this thread is a, a, a, fail.
Since they are pairs of parallel wire they could have the ability to record speed…Im not saying I know anything about them, just that they could.
a foot seperation between 2 sensors is a horrible horrible way to calculate speed /story
traffic counter/ story
It actually determines if you pay your taxes.
What the hell do you think its for?
[quote=“HotRodKid,post:6,topic:37960"”]
a foot seperation between 2 sensors is a horrible horrible way to calculate speed /story
[/quote]
:word: Way too much error if they were measuring speed.
And who the fuck cares about speed data anyways?
Impossible to calculate speed with varying wheelbase of different vehicles. Also, not to mention multi-axle trucks…
/story
[quote=“Avatar,post:10,topic:37960"”]
Impossible to calculate speed with varying wheelbase of different vehicles. Also, not to mention multi-axle trucks…
/story
[/quote]
lol
Can you figure out why that makes me laugh?
I agree that measuring speed with just a foot or two apart would be difficult but I’d like know the engineering reason why these always seem to have two not one.
[quote=“Fry,post:11,topic:37960"”]
lol
Can you figure out why that makes me laugh?
[/quote]
I was going to say the same thing, but I’m already over my quota for arguing on the internet this week. Damn illegal aliens.
[quote=“Fry,post:11,topic:37960"”]
lol
Can you figure out why that makes me laugh?
[/quote]
I’m certainly no engineer, but I can’t see a way to accurately measure vehicle speed of the multitude of vehicles traversing a road with two pressure sensitive lines spaced about a foot apart. I would like to know why that idea is so ridiculous…
Bam!
http://www.roadrampsystems.com/Welcome.html
Primarily used for counting, also for speed (hence multiple sensors) and classification (how many axles.)
[quote=“Avatar,post:13,topic:37960"”]
I’m certainly no engineer, but I can’t see a way to accurately measure vehicle speed of the multitude of vehicles traversing a road with two pressure sensitive lines spaced about a foot apart. I would like to know why that idea is so ridiculous…
[/quote]
I don’t care if a vehicle has 87 axles. The front wheels will always hit the wires consecutively. As long as you have 2 wires, you count how long between the first two bumps. Wheelbase and number of axles is irrelavent.
[quote=“Fry,post:14,topic:37960"”]
Bam!
http://www.roadrampsystems.com/Welcome.html
Primarily used for counting, also for speed (hence multiple sensors) and classification (how many axles.)
[/quote]
I see that for classification two sets of sensors are used. That makes sense.
Damn it, Fry found the same link I did.
http://www.roadrampsystems.com/Bypass.html
Took me a while to find the name for them. “pneumatic traffic counters”.
Fry beat me to it.
It can be used for traffic counting, speed sensing and axle counting.
Avatar, you’re wrong about needing to know axle to axle distance. Front wheel triggers one sensor, then “t” time later it triggers the second sensor. average V=delta X/ delta t
DURRR.
[quote=“Fry,post:15,topic:37960"”]
I don’t care if a vehicle has 87 axles. The front wheels will always hit the wires consecutively. As long as you have 2 wires, you count how long between the first two bumps. Wheelbase and number of axles is irrelavent.
[/quote]
I see that, but my point was that I thought it wasn’t able to calculate sped per vehicle (because of wheelbase/axles). Measuring one set of wheels is fine, but speed of one complete vehicle such as an 18-wheeler without confusing it with 3 cars wasn’t clear to me… Thanks
edit: I was thinking too complicated…