Weigh Stations?

Configuration and operational information about stumbled AP's

Weigh Stations?

Postby T-Train » Mon Apr 22, 2002 7:27 pm

Is it just me, or have other people noticed that weigh stations typically have 802.11b APs? I've passed multiple weigh stations in TN, KY, IN, OH, and MI, and I can only recall one that didn't give me two signals (one going each direction). On a particularly straight stretch of highway around a weigh station in TN, I held the signal for at least 4 or 5 miles. I'm assuming this has something to do with the "in-cab communication" I usually see referenced on the signs for the weigh stations.
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Postby Diablo » Tue Apr 23, 2002 11:52 am

I live right beside one. Its AP is called IRD. Strong signal too. It transmits various stuff to the truck as it approaches the station.
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Prepass Weigh Stations

Postby Gonarat » Thu Apr 25, 2002 11:45 am

Hello All,

I ran into several of these sites on I-71 and I-90 in Ohio when I went up to Erie, PA earlier this month. I did a little research via Google to see if I could find how it works. Although I didn't see much technical information, I found out the following:

Prepass is a system offered by Help Inc. to States where it has signed contracts. The system basically allows Trucks belonging to companies with good safety and regulatory histories the chance to bypass Weigh Stations. Each truck that is signed up received a little tranceiver device that is mounted inside the truck at the corner of the windshield. The device transmits a code that identifies the truck and receives a signal telling the driver if he can bypass the weigh station or if he must stop (green LED to bypass, red LED to stop). Help Inc. makes $4 and change each time a truck bypasses an open weigh station.

The system is set up (some of this is educated guessing) as follows:

There is a post with a transceiver on it over the road about 1 mile from the Weigh Station. There is also some kind of in-highway scale at this point. Netstumbler identifies its AP as "aaaa". I assume this is the AP that communicates with the device in the truck.
There is also an antenna on the pole at the side of the road that is pointed towards the weigh station. On I-71 NB North of Cincinnati, the AP was named "1701" (SB was "1702"). At the weigh station, there is another AP with the same name. So what looks like what happens is

1. The truck reaches the Prepass point on the highway one mile from the weigh station.

2. The "aaaa" AP polls the truck device, which sends its ID code. The ID code, some weight and height information is sent from AP "1701" at the pole to AP "1701" at the station. The system looks up the truck by Prepass ID. If everything is in order (truck info, weight, and height) the station AP sends a message back to the pole (and the truck) giving it a green light to bypass the weigh station. If something is wrong (or the station is closed) a red light is returned, telling the Truck Driver that he must stop at the Weigh Station (if it is open). The trucking firm is billed for each green light.

There are several companies and State run systems, go to http://www.prepass.com for information on Prepass, or Google prepass and you will find links to prepass and other similar systems.

Bill
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Weigh Stations in Calif.

Postby carbolic » Sat Apr 27, 2002 11:55 am

I've seen the same thing in California.

One of these stations right near me has an active repeater to make it out the one mile to the sensors. The geography is such that the station doesn't have LOS to the sensor. Interestingly, all of these stations in this network are named for the location of the weigh station. They all have the same SSID.
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repeater

Postby carbolic » Sat Apr 27, 2002 11:56 am

Here's a shot of the repeater.
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Postby Dr3D1zzl3 » Tue Aug 06, 2002 9:33 pm

Get alot of those up here to in nor cali.

right on 80 in cordelia there is a station (two stations, one for each way) SSID of 101 and 201 i think it was. If you ever pick up Numeric SSids like 101 or 205 most likley if you in ca its a station like this... I allso think that they use these for data gathering on traffic loads. (damn smart freeways)
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Postby WitchDr » Thu Aug 08, 2002 9:59 pm

The transmitters that are directional and pointed towards the road are 900MHz. They are used to measure the height and length of the truck and also they query a little dealy-bob on the windshield. It's all part of a in motion weighing system. With the transponder, the trucker can avoid going through the weigh station because it's done via this system on the fly. In Oregon it's called something like the Green Light program.
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