EZ Pass followup.

Trei, Peter ptrei at rsasecurity.com
Tue Jul 20 11:07:39 EDT 2004


This may be of interest to the folks discussing EZ pass.

On ne.transportation, there is a thread regarding
the subject, titled:

Surveillance Equipment on I-95?

The most interesting post follows.

Peter Trei

--------------------
From: john_s at no.spam

"John F. Carr" wrote:


	> In article  <cdhb6c$l7r$3 at pcls4.std.com> <mailto:cdhb6c$l7r$3 at pcls4.std.com>,
	> Michael Moroney  <moroney at world.std.spaamtrap.com> <mailto:moroney at world.std.spaamtrap.com> wrote:

		> >I noticed several unusual sensors on I-84 SB in Connecticut, just before
		> >and at a weigh station that's just north (IIRC) of Exit 71  These are
		> >overhead on a gantry, and some look like the old-style (large) security
		> >camera without a lens.  I figure they are somehow related to catching
		> >trucks bypassing the weigh station but how exactly do they work?

	>
	> I assumed they were part of the weigh-once scheme that is spreading
	> around the country.  A truck having been confirmed to be legal in one
	> state may bypass other weigh stations in that state or a cooperating
	> state.  Before the weigh station a transponder is interrogated and the
	> truck is not required to stop if the computers like it.
	>
	> Sometimes there are signs saying "follow signal in cab" or something
	> like that.


It is part of the weigh station bypass system.   <http://tinyurl.com/4hqc5>   If
the truck has a participating transponder, it can usually skip the weigh
station if everything is in order.  The transponder will display a green
light to bypass, a red means a trip to the weigh station.  The light stays on
for a few minutes so that compliance can be checked, if needed.  Some
stations have weigh-in-motion equipment to verify that the weight

There are two major weigh station bypass programs in North America: PrePass
and NorPass.  You can see what states they are used here:
<http://tinyurl.com/48twn>   Connecticut's weigh station(s) have been
compatible with NorPass for several years and they just joined NorPass as a
full member a few weeks ago.    <http://tinyurl.com/3oj99>

NorPass doesn't have any fees once you buy your transponder.  (PrePass
charges for each bypass with a daily maximum).  All systems use a compatible
transponder, and it is possible to buy a transponder that also speaks the IAG
protocol so it can be used at E-ZPass locations for tolls (after the
transponder is registered with E-ZPass).


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