EZPass Solution

EZPass Solution

Several people have commented on the lack of a windshield pass-through location for a toll transponder. It is supposed to be to the right of the rear view mirror, but most of us have found that it is intermitent at best and our windshield has no spot where it will work. We travel constantly on toll roads and bridges, so searched for a better spot.

There is a ready made location behind the car's plastic nose. The nose cap pops off with a little pressure under either of the lower corners. I used a towel-wrapped flat screwdriver to pop the first panel release. There are standard body panel press-fit attachment points around the panel - they won't break - be forceful, pry outward and it comes right off. Pry only under the shiny black plastic, everything else stays in place.

Interestingly, there is no space immediately in the front part of the panel. Although some on the forum have suggested they don't like the protruding nose (and a few say they plan to replace it with a grille), it is shaped this way to cover a heavy steel crossmember that forms the front of the car's crumple zone. I like the way it looks anyway, but there is no potential to install a fat or recessed grille or other cover. There is about 1/4" between the steel beam and the cover panel, so no place in front to put the pass. However, to the left and right of the beam there is a recess, with a flat steel plate that is the right size to hold an EZPass transponder. A little industrial Velcro, job done!

We had a license-plate mounted EZPass transponder on a prior car, but it is an ugly black bar, and we don't have a tag on the front of the Model S, so prefer the hidden method. A couple pictures here:

dr.jacks.tesla | 10 maart 2013

I thought someone tried this and it did not work.

nickjhowe | 10 maart 2013

@P_D - I have the license-plate-mount version of the Florida SunPass taped/tied to the front bumper behind the nose cone and it works great.

Pungoteague_Dave | 10 maart 2013


Why would it not work? It works great inmy setup.

It is higher than it woudl be for people using the plate-mounted version, and I mounted it on the left side, which is where the toll sensors look in MD & VA. The thin plastic nose material is invisible to the transponder, so it solves the issue completely. Took me less than five minutes, including the pictures.

andykeller | 11 maart 2013

That looks like a good solution. The picture looks like a regular old EZ pass, not the one that's designed for external use. Is that area waterproof? Does it matter? Did you bag it?

DanD | 11 maart 2013

There is one designed for external use, BUT you have to have a letter from your dealer to get one in NJ.

Has anyone secured such a letter?

P4768 | 11 maart 2013

I was able to pop off my nosecone this weekend and I used some industrial velcro to adhere a license plate EZ Pass transponder to the steel cross beam that runs below the nosecone.

The cone popped back on without any issues and my transponder was detected when I went through the toll booth that evening.

Mark Z | 12 maart 2013

After much failure with multiple front window positions, it was time to study Model S for another idea. The REAR hatch speaker grill appeared to be at a good angle, so I opened the hatch and found a perfect place for the transponder with NO modifications necessary. It is attached to the center recessed area on the bottom of the hatch. There is a handhold area where a portion of the transponder can be placed.

I had success when trying this most unique location. The angle is right when the hatch is closed and the recessed area seems as if it was made for a FasTrak device. More testing will be done soon. If it does not work 100% of the time as shown in the photo, then I will return it to the successful upside down position that worked yesterday. The best part is that the device is NOT attached to the window. The speaker grill on the window side appears to be made of plastic and does not interfere with the transponder.

Do NOT attach decals or adhesives to any inside rear window to avoid moisture damage to the heating wires.

CC | 12 maart 2013

@Mark z

Are tints safe for the rear window defroster wires? My son sits in the jump seats in the back and is complaining it's too bright and hot when the sun is shinning behind the car.

Mark Z | 12 maart 2013

I would hope that the manufacturers of most tinted plastic film would be fine. I am glad you asked the question so I could share my experience. I used a small PBS window cling on the rear window of a 1994 Cadillac Eldorado. Years later when I removed the cling, it had hardened to the glass. I figured moisture may have caused the damage to the now corroded conductors that had small cracks in the copper where the cling was placed.

Decreasing the solar heat in the rear seating area is critical and I would not want my comment to cause concern about tints.

Can it happen? Depends on the car model according to this thread:

Vawlkus | 12 maart 2013

It can be done, my old Mustang had the rear window tinted and that did not bother the rear window defrost wiring. Unfortunately, I bought that car used, so I've no idea who or how it was applied.

Mark Z | 12 maart 2013

Just returned from a quick round trip on the 91 Express Lanes. The new transponder location mentioned above has now worked 3 out of 3 times! Appears that it could be the solution for those who must be able to set the number of passengers before driving on our newest Toll Roads. It would require opening the hatch before sitting in the driver's seat, but the access is easy when placing items or passengers in the back.

The double beep is hard or impossible for the driver to hear at the hatch mounting location. To check if it works, I used an extra iPhone and recorded a voice memo. The phone fits nicely in the cover handle, faced the microphone towards the front and took note of the start time and when driving through the toll. The tones are clearly heard when playing the memo back.

Enjoy trying this successful rear hatch FasTrak location. Don't forget that if you sign up with 91 Express Lanes, ZEV Tesla travel is free or discounted on the 91. No discounts or free programs with The Toll Roads.

Mark Z | 14 maart 2013

This should be the last thread to "edit." Sorry for the duplications. If only we could edit our previous entries!

This mirror mount location WORKS PERFECTLY. Here is a photo:

I received a response from "The Toll Roads" today. Please DISREGARD MY SUGGESTION of the rear hatch location. While it works and it's not on the glass, the Highway Patrol could be upset. Here is the reply:

"Thank you for contacting The Toll Roads.

In accordance with the California Vehicle Code, it is not permitted to place the transponder in the rear window.

The internal transponder may be placed on the lower left-hand side or right-hand side of your windshield or behind the rear view mirror where it will not obstruct your sight while driving.

At times, we have found that the polarized windshields have prevented the internal transponder from reading at all times. Therefore, it may be necessary to replace your internal transponder with an external one.

This recommendation is presented in situations when the internal transponder fails to read while properly mounted and generates a significant number of tolls which are paid by the license plate number instead of the transponder number.

The external transponders mount directly to the front license plate brackets and are secured with tamper-resistant screws. A special tool is provided in order to remove/affix the external transponder."

Brian H | 14 maart 2013

You can. Hover the pointer over the logo, and select Edit. Then move to "None Selected".

vivivan | 17 april 2013

If you attach the EZPass transponder to the black stem holding the rear view mirror (on the black plastic, just on top of the mirror), not touching any glass) it will work!

CarlE_P439 | 18 april 2013

Ditto. I've had no problems with mine attached just to the left of the rear view mirror stem (placing it right on the black plastic base). If you look on the outside of windshield near this location you will see a hole (presumably for the Homelink; that may by why this works). Not sure why people are struggling with this (at least the NY EZ Pass folks).

Xerogas | 14 mei 2013

This may sound like a dumb question, but how is it that people on this thread *know* that the transponder is working? When I drive in HOV lanes with my old car, I get no feedback at all when driving under the electronic receiver structures on the freeway. It doesn't beep or anything, but in a few weeks I eventually do get billed on my transponder statement.

So when I get my Tesla, and I put the transponder somewhere on the windshield, how will I know if it's working? For that matter, how does a cop know that it's working?

(Hopefully my white HOV stickers will arrive quickly, so I won't need the transponder any more)

CC | 14 mei 2013


I have been going through the toll booth to test the EZ pass, it will say accepted on the toll booth screen if it works. After i made sure it works, then I started using the EZ pass lanes (fast lanes, no booth).

Pungoteague_Dave | 15 mei 2013

You can tell it works when you get the monthly bill. At Maryland bridges there's also a visual "paid" signal at the toll booths, even the 15mph units. However, there is no indicator on roads like the Dulles toll road in VA or the ICC in MD, so I verify by checking the bill.

Mark Z | 15 mei 2013

@Xerogas; In Califorina the FasTrak responder beeps twice while driving under the sensors. Mounting it on the flat part of the mirror mount has worked perfectly. The Velcro strip must be moved or it can be positioned in a portrait rather than landscape orientation. In landscape position part of the transponder will hang over the mount and be visible through the glass. That will help the CHP if they stop the driver and check for a recommended mounting location.

Xerogas | 15 mei 2013

Thanks, @Mark Z, so that means my FasTrak transponder's beeper is malfunctioning. I pay for the HOV lanes all the time, and I get billed, but no beep...guess that explains my confusion...

JZ13 | 15 mei 2013

I followed the advice of another poster a few months ago who put his transponder in the rear-hatch door. There is a slot on the inside of the hatch that the transponder tucks away and the signal works great. I can tell because I have received my bill and it indicates if the transponder was read or if they needed to bill you to your license plate. On my most recent bill, all of the readings were from the transponder. The only potential problem I face is if an officer is parked on the side of the highgway looking for mounted transponders. If I get spotted and pulled over (IMO very unlikely) I have a very good explanation as to why it's not mounted on my windshield.

Keith72 | 15 mei 2013

I never could get the windshield pass to work, and tried many locations. My neighborhood uses EZ Pass to open the gates, so I needed to find a way for it to work. I finally got the transponder that is supposed to attach to the front license plate, but since I opted not to install a front license plate, I installed it behind the nosecone (actually the Houston Service Center was kind enough to install it there for me). It works fine for the highway, and most of the neighborhood entrance gates. I've found a couple that won't open, but not really an issue.

Hodas | 4 juli 2013

As Mark Z mentioned, our new Los Angeles FastTrak needs to be mounted somewhere convenient, because our transponders have a switch to set how many people are in the car, as HOV access/charges on the 110 and 10 freeways varies for time of day and number of passengers.

Fortunately, the spot next to the rearview mirror seems to be working ok for me.

I was faced with the problem of ALSO having an RFID credit-card-style parking pass for work. I was going to just live with swapping it and the FastTrak as needed (fortunately my FastTrak use is mostly on the weekends), but I discovered that velcroing it to the inside of the small triangle of glass at the front part of the driver door works. You could not fit a FastTrak/EZpass there, but for card-style transponders this appears to be an option.

JimAlger | 21 september 2014

Assuming u have hov stickers no change is necessary. HOV 3+ stays at all times for free access HOT lanes

perlovl | 21 september 2014

Raleigh, NC Tesla Service just told us, "Go get the big ugly transponder, then stop by". They mounted behind the nose cone, washed the car and sent us on our way; no charge.

Also, we checked to make sure the transponder was working in both NC and FL by logging onto the State's websites and looking at the transaction histories. So far, no failures after dozens of uses.

Haggy | 21 september 2014

One problem is that FasTrak transponders in Northern and Southern California are different. The Bay Area ones have no switch. So mounting them permanently means paying tolls in lanes that should be free, if there's no way to turn them off. The Bay Area website is a confusing mess, and makes conflicting statements. It has a list of cars, including those by Tesla, for which it says an exterior (gray as opposed to ivory) toll tag is needed. It also says "Please click here for special instructions for obtaining a toll tag for your hybrid vehicle." That section mentions that EVs qualify, but the page says nothing about how to obtain a toll tag for your Clean Air Vehicle. It simply says that you use the standard one, but use it as if there were multiple passengers. Does anybody know if a "FasTrak for Clean Air Vehicles" exists or ever existed?

The next question I have is whether a southern California transponder could be registered in the Bay Area. California law requires the systems to be compatible, and out of the box, the transponders do nothing. It's necessary to go to an account (or set one up) and put in the Toll Tag Number & Validation Code. So if I buy one in southern CA, and the guts are more or less the same, then would the 10 digit tag number and 8 digit validation code work? I've never looked at the packaging in a retail store such as Costco, but are there any differences in the packaging to indicate that they should be registered in a particular area, aside from the service center address printed on the transponder?

If the systems are supposed to be compatible, it would make sense that a person from Southern California traveling in an HOV lane in the Bay Area, and with the switch sent to 3 passengers, should not be billed. I can't see how the systems could be considered compatible otherwise, and there's no sign saying to remove the transponder. So if the law says they should be compatible systems, I can't see why the Bay Area doesn't simply source parts from the same place and issue new transponders with switches.

If there's a way around it such as registering in the "wrong" part of the state, that would be good to know.

sberman | 21 september 2014

@Haggy, you can contact the Southern California toll agency via email using the form here, or phone (949) 727-4800 during normal business hours.

Haggy | 21 september 2014

I figured I could call them or call the Bay Area one and I suspect that the people who answer the phones may know what happens if I use one with a switch in an area where switches aren't used. But I don't know if they would be able to answer the registration question or if they'd just say that I'm not supposed to do that. That might be how they were trained rather than because of a technical knowledge.

Lpearson | 6 april 2015

I'd like to renew this thread as I am having no luck getting my JANUS-model Kapsch-make E-ZPass to work on the Dulles Greenway.

I've tried mounting it on the license plate, per E-ZPass instructions with no luck. I've tried mounting, literally, on the outside of the windshield, top middle where an internally mounted pass would normally go, except on the OUTSIDE of the windshield. None of these options has registered for me, either in the main lane tolls, or on the smaller exit ramps.

I'm wondering if there are any Tesla owners out there who regularly drive the Greenway and have solved this problem, short of hanging the tag out the window.

What is interesting is that I've had to deal with three different toll operators to try to resolve this. My commute takes me along the Dulles Greenway (operated by the privately owned Dulles Greenway Partners), the Dulles Tollroad (operated by E-ZPass), and the IH-495 Express Lanes (operated by ExpressLane). I call each with my issue and they tell me to call the other guy. Tired of the run-around.

I've also contacted my local Tesla dealer (Rockville, Maryland) to see if they can track down some other Tesla owners in the area. Would love to hear from some Tesla owners in the Leesburg/Purcellville area on this.

murphyS90D | 6 april 2015

What model car do you have? I looked up the Janus interior transponder and it looks exactly like the one issued to me by PA E-ZPass. I have a pre-autopilot car. It is mounted to the right of the mirror base, touching the base and high as possible, and is rotated 90 degrees counter-clockwise from the recommended orientation. It works on the PA Turnpike, the DE tolls on I95, the I95 tolls in MD, and the Fort McHenry tunnel. I have not tried the Express lanes on 495.

When you mounted the transponder outside of the car was the label facing the passenger compartment? The base that normally gets glued to the windshield has to be facing forward. It would have to be on the windshield. If mounted on the aluminum roof the aluminum would absorb the radio signal that it is trying to transmit.

1PT1 GEE | 7 april 2015

@Lpearson: Maybe you have a broken EZPass transponder? Not sure if those break, but my Fastrak transponder broke last year.

brian_in_TX | 7 april 2015

I realize this is probably only marginally helpful, but because I think the transponders are ridiculously ugly, I don't mount mine anywhere. I keep mine in the center storage compartment, where it lives with a box of Altoids and usually a receipt or two. When I come up to an EZ-PASS reader, I pick it up and hold it out of the window or sunroof.

This is less pleasant when it's snowing or raining, but it works every time. Like I said... probably not the most helpful tip, but it works in my world.