The E-ZPass Interagency Group (IAG) consists of member agencies in several states, which use the same technology and allow travelers to use the same transponder on toll roads throughout the network.

E-ZPass tags are active[1] RFID transponders, historically made by Kapsch TrafficCom (formerly Mark IV Industries Corp—IVHS Division) under a competitively bid contract.

They communicate with reader equipment built into lane-based or open-road toll collection lanes by transmitting a unique radio signature.

New York also offers green-colored E-ZPass tags (and a 10% toll discount plan) to qualifying low-emission and zero-emission vehicles.

This network provides the means to exchange tag data and process toll transactions across the various agencies.

[10][11] As of 2022[update] this is a partial list of states that will expire an E-ZPass account for inactivity: Some issuing agencies offer a packaged E-ZPass transponder preloaded with toll funds sold over-the-counter at a retail setting such as a supermarket or pharmacy service desk that is valid immediately.

According to the Port Authority of New York and New Jersey, 83.4% of vehicles crossing its six bridges and tunnels used E-ZPass for toll payment during all of 2016.

[41] On October 6, 1998, a U.S. patent for an automated toll collection system was issued to Fred Slavin and Randy J.

[50] On December 16, 2008, Rhode Island joined the network by activating E-ZPass lanes in the state's only toll booth, at the Claiborne Pell Newport Bridge.

[52] On November 9, 2017, the Central Florida Expressway Authority (CFX) announced that it was joining the E-ZPass group.

Under MAP-21, passed in 2012, all ETC facilities in the United States were supposed to have some form of interoperability by October 1, 2016; however, no funding was provided for this effort, nor were penalties established for failure to meet this deadline, and as of September 2018[update] this has yet to be accomplished.

[58] The Pennsylvania Turnpike Commission, which had been studying going towards all-electronic tolling in order to cut costs, implemented such a system for non-E-ZPass users in 2020 due to the on-going COVID-19 pandemic.

[61] The Port Authority reports that drivers save an average of 15 seconds by opting to pay for airport parking using E-ZPass.

[63] In late 2012, the I-495 HOT (high occupancy toll) lanes in Virginia introduced the E-ZPass Flex transponder.

[65] As of 2021[update], E-ZPass Flex devices are currently issued only by Virginia, Maryland,[66] Minnesota,[67] and North Carolina.

[75] A study published in the American Economic Journal: Applied Economics, "Traffic Congestion and Infant Health: Evidence from E-ZPass", compared fetal health outcomes for mothers living near congested and uncongested toll plazas on three major highways in Pennsylvania and New Jersey.

The researchers focused on areas where toll plazas had instituted E-ZPass, which, because cars travel through more efficiently, diminishes congestion and pollution.

The study drew its conclusions by looking at the health outcomes of nearly 30,000 births among mothers who lived within two kilometers of an E-ZPass toll plaza.

The researchers state that their findings "suggest that the adoption of E-ZPass was associated with significant improvements of infant health."

[77] Civil liberties and privacy rights advocates have expressed concern about how the position data gathered through E-ZPass is used.

As of August 2007[update], several states that employ E-ZPass had provided electronic toll information in response to court orders in civil cases, including divorces and other non-criminal matters.

The New York State Department of Transportation (NYSDOT), for example, collect transponder information to provide real-time estimates of travel times between common destinations.

This information is also used to determine the best times to schedule maintenance-related lane closures and for other traffic management purposes.

According to NYSDOT, the individual tag information is encrypted, and is deleted as soon as the vehicle passes the last reader, and is never made available to the department.

[84] The Triborough Bridge and Tunnel Authority (TBTA) in New York City once imposed a monthly account fee starting on July 1, 2005, claiming to defray the administrative costs.

Since the lots only charge for parking during the twelve days of the State Fair, mobile, self-contained E-ZPass units were used to process vehicles.

The units were mounted on trailers with a collapsible gantry for the E-ZPass antennas, used a cellular wireless connection to send transactions to the NYSTA back-office system, and were powered by batteries that were kept replenished by photovoltaic solar panels, with a generator for backup.

[126] In 2018, a one-year pilot project with the startup Verdeva was announced to test drive-thru and gas station payments via separate accounts set up with the E-ZPass system.

[127] In December 2021, PayByCar launched a pilot program to accept E-ZPass (or its own RFID stickers) at 27 Alltown gas stations in the Boston area.

[131] However, the congressional legislation did not include any penalties for agencies and states that failed to comply with the implementation of such a system.