is an electronic toll collection
Electronic toll collection , an adaptation of military "identification friend or foe" technology, aims to eliminate the delay on toll roads by collecting tolls electronically. It is thus a technological implementation of a road pricing concept...
system in Houston, Texas
Houston is the fourth-largest city in the United States, and the largest city in the state of Texas. According to the 2010 U.S. Census, the city had a population of 2.1 million people within an area of . Houston is the seat of Harris County and the economic center of , which is the ...
, United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
that allows motorists to pay tolls without stopping at toll booths. Motorists with the Tags are allowed to use lanes reserved exclusively for them on all Harris County Toll Road Authority
The Harris County Toll Road Authority maintains and operates a toll road system in the Houston/Harris County area...
roads. As of late 2003 the EZ TAG can also be used on all lanes of tolled roadways in Texas that accommodate electronic toll collection.
How it works
To participate, drivers sign up through the EZ TAG website, via telephone, or at one of the store locations. Next, the customers receive a small, white radio frequency transponder
In telecommunication, the term transponder has the following meanings:...
which must be affixed to the insides of their windshields behind their rear view mirrors. Finally, when passing through a toll plaza, drivers choose lanes specially equipped with sensors that can read EZ TAG transmitters and deduct the appropriate amount from their accounts.
EZ TAG users are also unwitting participants for Houston TranStar, which provides transportation management and emergency management services to the Greater Houston Region.
Houston Transtar uses EZ TAG sensors all over the city for their Automatic Vehicle Identification (AVI) traffic monitoring system. By tracking the movement of individual transponder tags (EZ TAG users) over the city, the system can generate real time traffic information for use by the general public. The personal information about the EZ TAG customer is not compromised in this process because the EZ TAG database and the AVI system are not interconnected. To the AVI system, an individual is 'just a number'.
The "New" EZ TAG
In May 2006, HCTRA introduced a new version of the transponder tag. Instead of battery-powered radio transmitters, the new tags are adhesive stickers with a button-sized microchip in the middle of, and a reflective antenna system throughout the tag. These new tags are sold, rather than rented, so they help save money over the life of the tag by eliminating the monthly $1 rental fee. The battery tag's $15 security deposit can be applied to the purchase of the sticker tag.
Removing the sticker after placement has a high probability of either separating the chip from the antenna, and/or de-tuning the antenna from its designated frequency, therefore invalidating the tag for future use. The tag also relies on the windshield for an amplification effect, and its effective range is greatly reduced if it is not mounted on a glass substrate. This range reduction is so much that not having a tag properly mounted will result in it not reading at all in toll lanes.
These characteristics are much different compared to the old battery tags, which would read fine if not mounted properly. As such, some toll patrons are attempting to 'hold up' their sticker tags when driving through the toll lanes, and appear mystified when they do not work as their old tags did.
The new tag uses three different protocols, or communications methods, with the tag readers - ATA, eGo and SeGo. The protocol used in Houston is ATA, however a driver in Houston can conceivably use the tag in another state where the other protocols are used. HCTRA is working on the interlocal agreements that will make this happen.
New EZ Tag Variations
As of January 2008, three different sets of EZ Tags have been released. The differences are purely cosmetic.
Despite the similarity in the names, EZ Tags are not compatible with the EZ-Pass system in the northeast U.S.