Rubber coated cord across the road
- Thread starter locolukas
- Start date
As there are two strips it would be very easy for it to measure speeds by checking the time between pulses. I used to jump on those almost simultaneously when I was a kid to try to register a high speed (or bunny hop over one of the strips to try to confuse it). Yes I was a total rebel and hooligan :rolleyes.
Sometimes you see them with just one strip - I would guess those ones are 'count only'.
Sometimes you see them with just one strip - I would guess those ones are 'count only'.
splat
Well-known member
Drive over them at or slightly above speed limit.
The data collected helps on whether they need to or can modify the speed limit on that road (if it says speed limit is 45, and everyone drives and average of 35----boom! 35 it is.) If it's labeled 15, and everyone drives 30, it'll probably go to 25. It also helps with measurement of amount of traffic.
Depending on location and sophistication, it can tell if traffic is headed one way or the other (whether A is tripped first or B is). But they're pneumatically operated much like those found in older oil-change or service stations.
Think of them as data collectors. Speed across them if you think speed is artificially low there, slow down if it's your neighborhood, do either of those at your own legal risk.
The data collected helps on whether they need to or can modify the speed limit on that road (if it says speed limit is 45, and everyone drives and average of 35----boom! 35 it is.) If it's labeled 15, and everyone drives 30, it'll probably go to 25. It also helps with measurement of amount of traffic.
Depending on location and sophistication, it can tell if traffic is headed one way or the other (whether A is tripped first or B is). But they're pneumatically operated much like those found in older oil-change or service stations.
Think of them as data collectors. Speed across them if you think speed is artificially low there, slow down if it's your neighborhood, do either of those at your own legal risk.
Shaggy
Zoinks!!!!
I don't think they measure speed. The varying wheel bases of different vehicles would screw up the data. A motorcycle at 25mph v. a school bus at 45mph might have the same pulses, yet one is moving significantly faster.
I think they just count passes then divide by some number close to 2 to figure out the number of vehicles.
I think they just count passes then divide by some number close to 2 to figure out the number of vehicles.
Flying Pig
Still learning to ride
It is plausible though. I used to think that the wheelbase would be an issue, but they usually have the 2 cords relatively close together indicating that they can measure the time it takes for each tire to cross, which would indicate how fast each tire is crossing by
artyBut this is purely my own speculation. I have nothing to really base this off of
Traq
Well-known member
Wheel base wouldn't have an impact on speed calculations when there's 2 tubes. That said, they typically aren't measuring speeds. When they put out 2 tubes it is just to ensure they get an accurate count during the period they want to monitor (i.e. in case 1 tube fails the other is a backup).
The axle count number will depend on the expected mix of vehicles for a particular location. On a residential street it'd be 2 or very nearly 2. On a freeway onramp it'd be higher since there are vehicles with more than 2 axles.
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Beauregard
Aut Agere Aut Mori
Traffic tally. You can sell it on Ebay for $200.00.
tgrrdr
Не мои об
I've never heard of multiple tubes used this way. Typically (most commonly) they are used to count traffic in two lanes in the same or opposite direction. They can also be used to determine vehicle speed, type, spacing between vehicles etc.
