Current system status
The TxTag brand name is used on the following highways:
- Operated by TxDOT:
- the Central Texas Turnpike System, which encompasses Highway 130, bypassing Austin to the east, Highway 45, an east–west road roughly straddling the Austin-Round Rock boundary, and the northern portion of Loop 1 (Mopac) on Austin's north side
- Loop 49, bypass of Tyler
- Highway 255, the Camino Colombia Toll Road, as of June 1, 2009. 
- Operated by the Central Texas Regional Mobility Authority :
- EZ TAG, operated by Harris County Toll Road Authority and Fort Bend County Toll Road Authority (Greater Houston)
- TollTag, operated by North Texas Tollway Authority (Dallas–Fort Worth metroplex)
Since 2003, HCTRA's EZ TAG and NTTA's TollTag have been mostly interoperable, with the exception of Dallas/Fort Worth International Airport and Dallas Love Field airport parking, where NTTA's TollTag is the only ETC system recognized. TxTag transponders are accepted at all designated lanes on HCTRA and NTTA roadways. EZ TAG and TollTag are accepted at any TxTag locations.
TxTag transponders are currently not accepted:
- At tolled border crossings with Mexico, although future interoperability is planned with the Laredo Trade Tag accepted at four crossings.
- By any toll authority outside of Texas.
TxTag uses at least two types of transponders manufactured by TransCore: legacy hard case AT5100 transponders and newer eGo Plus flexible sticker-type transponders. The transponders are mounted on the inside of the vehicle at the top center of the windshield. The TxTag sticker can be used as a portable device, provided it is affixed to a small square of glass instead of a windshield. According to the patent for the device, the sticker was specifically designed such that if removed, among other things capacitor 66 is decoupled from 64, preventing the use of the sticker if it is torn from the glass. It would also appear the sticker can be simply taped to the inside of the windshield for temporary use.
- North Texas Tollway Authority
- EZ TAG
- Pikepass used in Oklahoma
- K-Tag used in Kansas
- Fastrak used in California
- Sunpass used in Florida
- I-Pass used in Illinois
- GeauxPass used in Louisiana
- E-ZPass used in Delaware, Illinois, Indiana, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Virginia, and West Virginia