When driving through a toll both with a transponder, it is common to have some form of display feedback to the driver. For example, the US state of Maryland has an explanation here showing the three key components of the system (from a user perspective), including #3, the Driver Feedback Display.

Apparently, the US state of Pennsylvania used to have such indicators, but removed them in 2017, and now drivers going through an equipped tollbooth have no way of knowing whether or not the read was successful without going online to check their account a sufficient number of days later to allow time for the read to post, or phoning the turnpike authority.

This seems like a pretty bad UX decision. Yet it was intentionally made, reportedly "due to a change in federal guidelines." The change in guidelines also seems to have been intentionally made for some reason or set of reasons. What are those reasons? Why is this change considered a good thing to expend time/money/effort on?

Hypothesis: This change could impact speeds at tollbooths. For example, if a tollbooth is signed 5mph, and a driver is approaching it at 10 but sees the light acknowledging their tag was read, the driver may just continue through without slowing down further. In the new condition without the lights, drivers may be more likely to slow down more and go through at a crawl to try to increase the probability of a successful read (assuming higher fines for read failures, as is often the case). Any studies about that are welcome in answers.

This would seem likely to increase congestion around tolls and increase environmental costs of tolls, but speed enforcement at 5mph tolls may be a public policy goal, to promote strict rule-following in general. (Is that the reason?)

  • Do you have boom barriers on US toll towers? Commented Jan 19, 2020 at 13:29
  • @ADOConnection The Pennsylvania tolls in question do not.
    – WBT
    Commented Jan 19, 2020 at 22:35
  • what will happen if you pass toll tower and your transponder will not work? Commented Jan 20, 2020 at 21:28
  • 1
    @ADOConnection Apparently they take a picture of your license plate and impose a hefty fine, if you do not yourself notice (by checking the account online) and call them within a short window of time between when transactions post (days after they happened) and a deadline. Or, you could skip the transponder-only lane and go to a cash lane, where you pay cash in addition to having the same amount deducted from the transponder account.
    – WBT
    Commented Jan 21, 2020 at 13:20

1 Answer 1


These changes were made by the DOT to facilitate traffic flow and improve vehicle safety in and around toll plazas.


Green, amber, and red lights are part of standardized system to communicate right of way to drivers via traffic control signals, i.e., stoplights or traffic lights.

Toll plazas like those mentioned in Pennsylvania have been repurposing these same lights to provide toll payment feedback, using green to indicate success, amber to indicate low balance, and red to indicate failure.

The original choice to repurpose traffic lights in these installations introduces the risk of drivers interpreting them as traffic control signals. For example, a driver with a low prepaid EZ-Pass balance could interpret the amber light as an instruction to slow down or yield, resulting in an unintended disruption of traffic flow.

The change only impacts toll plazas that rely on indicators which closely resemble traffic control lights, i.e., stoplights. For example:

Fort Washington interchange of the Pennsylvania Turnpike. Notice how the toll indicator lights are actually just horizontally-mounted traffic control lights

Recommended Feedback System

The DOT recommended payment feedback mechanism is the Driver Feedback Display seen below:

The EZ-Pass Driver Feedback Display. Visible only to the vehicle passing through the toll, this system communicates information to the driver about their payment and EZ-Pass balance.

Details on New Regulations

Guidance on these systems is provided by the DOT via the Manual on Uniform Traffic Control Devices for Streets and Highways. Within this document, Section 4K.01 Traffic Signals at Toll Plazas states that:

Standard: Traffic control signals or devices that closely resemble traffic control signals that use red or green circular indications shall not be used at toll plazas to indicate the open or closed status of the toll plaza lanes.

Guidance: Traffic control signals or devices that closely resemble traffic control signals that use red or green circular indications should not be used for new or reconstructed installations at toll plazas to indicate the success or failure of electronic toll payments or to alternately direct drivers making cash toll payments to stop and then proceed.

Related Research

In 2006, DOT commissioned a consulting agency to prepare State of the Practice and Traffic Control Strategies at Toll Plazas: Best Practices.

The full history of the change is in National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for Streets and Highways; Revision; Final Rule.

  • I appreciate the detailed answer and the recommendation to have a Driver Feedback Display with the "EZ Pass Paid" as shown, even though that is perhaps less accessible to those with low English literacy. However, in the time at least preceding my question post, the driver feedback indicators had been completely removed leaving no feedback about whether or not the transponder read was successful or if a lack of prompt followup action after the trip would result in a fine by mail. Is there guidance that nothing is also better than the red/yellow/green?
    – WBT
    Commented Dec 24, 2020 at 19:46
  • @WBT: Looking at this through that lens of prioritizing safety, it is in fact better to remove the red/amber/green indicators even if an alternative mechanism is not yet in place. I'm wondering if the toll plaza(s) you're referring to are in the process of being converted to use the Driver Feedback Display system. Commented Dec 25, 2020 at 20:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.