The temporary ones that are used for surveys come in two types - single
hose and dual hose. The dual hose ones can differentiate between lanes,
and count the two lanes separately.=20

Both types count axles. Old analog ones had a simple chart recorder(for
time/density patterns) and a numeric counter. New ones are digital.

Exact accuracy isn't that important for surveys, so it doesn't matter if
it's a pickup pulling a trailer or two cars.

At least that's the info I got when I struck up a conversation with a
guy servicing one once :)

Cheers, Bob


On Tue, Jul 8, 2014, at 01:23 PM, John Guillory wrote:
> Anyone familiar with how they count cars using those long wires across
> the road?  I'm wondering how accurate it can be.  Eg.  Two lanes and two
> cars side by side hit the wire at the same time.  Does it count 2 or 1?=20
> And a truck with a boat trailer with 2 axels on the boat trailer,  does
> it count as 1 or 2?  An 18 wheeler, does it count as 1 or 2?  A dually,
> does it count as 1 or 2?  Seems like a lot of factors they can't count
> on...  And speaking of which, say some idiot is riding your bumper, does
> him and you get counted as one small 18 wheeler, or 2 cars?
>=20

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