I'm coming to the conclusion that the Tesla Model S windshields have a design flaw, in that they were not designed with electronic toll collection devices in mind, such EZ-PASS and the equivalent for other states. I know that the windshield has an infrared reflecting coating that blocks heat and that it also blocks the radio waves emitted by electronic toll collection devices. Other cars, such as Mercedes, have similar coatings, but their windshields have several square spots without such coatings specifically designed for toll collection devices. As one would expect, the service staff of other car companies know about these magic spots, and they are documented in manuals and even on video -see following link:

I've just inspected an S-Class Mercedes windshield at a local dealership and was able to see the square spots when I looked at it from a 30 degree angle in regular indoor light that was not too reflective. The windshield is a slightly different color (darker) within these squares and it is obvious that something is different there.I have spent a long time, under a variety of lighting conditions, looking for something similar on my Model S Tesla and have not seen been able to locate anything resembling the spots on the Mercedes. I can't help but conclude that there are no such spots on the Tesla S.

There are several Tesla threads and Tesla Club blogs that contain a variety of inconclusive personal opinions on where to place EZ-Pass-like transponders on the Model S windshield. The two spots that seem to be most popular are: right below the rear view mirror and on top of the dotted area to the right of the rear view mirror. I've tried both spots in my travels on the New Jersey and Pennsylvania turnpikes and have gotten inconsistent results; sometimes my transmitter registers at the toll booths and sometimes it doesn't. Whenever it doesn't register, I get charged a flat $5 fee instead of the $1-2 fee I should have gotten charged. So far, my EZ-PASS account has overcharged me somewhere close to $40. Talking to the EZ-PASS people about my problem has been a lot of fun. :(

I expect to get misinformation on blogs, but I expect more reliable information from the people who work at Tesla. Most of them have no clue about this issue. The people who work at the Owner Experience 800-line have their own varying opinions on where my EZ-PASS should be placed. One adviser (I'll protect his identity) wrote me the following in his email:

"I spoke with you yesterday regarding the placement of a transponder in the Model S. I talked with several different people before coming to the conclusion, directly under the rear view mirror is the ideal location for a transponder, or toll reader device. The area directly under the rear view mirror is lacking a coating which is applied to the rest of the windshield, thus allowing the signal to transmit more efficient."

Another adviser (I'll protect his identity as well), wrote me the following:

"Here’s the IR transponder install photo. It should help you install" This email included a photo showing that the transponder should go in the dotted area immediately to the right of the rear-view mirror. (I've checked with a local auto glass installer, who told me that the dotted area has a purpose - to block the sun when it is at an angle that would create a blind spot for the rear-view mirror. He could not find any spots on the windshield that looked like they were missing an infrared coating and shrugged his shoulders.)

So, the people on the front line of Tesla don't know any better than the individual owners who blogged about it.


I love driving my Model S and think that for the most part, the car is extremely well engineered. However. I would appreciate it if Tesla would not allow the first few thousand owners to have to spend needlessly wasted time looking for a magic spot on the windshield that doesn't exist and paying many toll violations before discovering that there's something wrong. We're your best sales people- your ambassadors - your partners - be honest with us and get your act together on this.

My next step is to investigate the possibility of installing an outdoor EZ-PASS transponder. It is usually installed on the front license plate, but we don't have front license plates in Pennsylvania. So, I'm going to try to install it underneath the black plastic piece on the front of the car. I'm hoping that my local service manager will help me with that.

nickjhowe | 28 febbraio 2013

Not sure why this needed a new thread rather than this one, but regardless, there is info in that thread about mounting a transponder behind the nose cone. Any transponder that is designated for a license plate install can be installed behind the nose (which pops off and is only held on with auto clips). The transponder can be taped, tied or screwed to the front bumper, works perfectly (in my experience better than any transponder I've had in any of my cars) and is completely invisible.

But I agree with your main point that there is so much misinformation that it points to a screw up of some kind. Seems to fall under Hanlon's Razor - probably more likely cock-up than conspiracy.

DFibRL8R | 1 marzo 2013

Newer transponders in the DC area are selectable if you have more people traveling in your car for reduced rates (free) in "HOT" lanes. This requires access to the transponder which would be pretty tough if mounted in the nose cone. Only solution I can see is holding out the sunroof or window when approaching.

DanD | 1 marzo 2013

I've been struggling mightily with this as well. No good answer from Tesla. NJ EZ-PASSS says I need documentation from the dealer proving why I need a different transponder.

I'm racking up fees and penalties trying to test this dumb thing.

I think we're on our own solving this.

bp | 1 marzo 2013

RFID tags work in the black dot area right of the rear view mirror and the top of the windshield

Norbert.Vienna | 1 marzo 2013

this was discussed already maybe you find an answer here

DanD | 1 marzo 2013

The NJ EZ-Pass tags DO NOT work in the dot area. That is you can't use them on the NJ Turnpike.

That's that thing what should work doesn't seem to be working and certainly not well enough to avoid being fined.

sidney_wang | 1 marzo 2013

I tried to place my community gate transponder at every possible location on the windshield, but none works. However, the place that works for me is placing the transponder on the left-most part of the dashboard, near the tiny triangle window on the driver side. Apparently that tiny window has no coating on it. I guess it also depends on where the receiver is located at the toll booth.

andrea.elwork | 1 marzo 2013

Some people keep repeating that the dotted area to the right of the rear-view mirror or the area below the rear-view mirror is the magic spot, but THAT IS NOT TRUE! Read my original note above- I've tested it extensively and found that the transponders only register their signals some of the time in those areas. Other times result in violations that show up several weeks after going through a toll plaza. Getting these violations straightened out with the EZ PASS folks is a royal pain.

Go look at a Mercedes S-Class and you'll see for yourself how these magic spots are supposed to look. Tesla has not owned up to it yet, but mark my words: they did not design the windshield with these toll collection devices in mind! The engineers goofed and have not told their service people to own up to it. In the meantime, owners are wasting an enormous amount of time and energy on this problem - all for nothing.

The latest news in my very time consuming saga is that the EZ PASS people are telling me that they no longer make available the outside transponders that are designed to go on the front license plate area. I'm now waiting for a supervisor to call me to see what they can do to help.

Having spent $73K on the car and needing to use turnpikes almost every day in all kinds of weather, I hope that I don't have to pull down my windows and stick my arm out with a transponder in hand for the rest of the time I own this vehicle! I wish someone higher up at Tesla would step us to the plate and do the right things! | 1 marzo 2013

Maybe EZ PASS should step up and do the right thing - i.e. make a system that works reliably for ALL cars. Clearly they really don't care, since they make more money because of the poor system design.

Keep in mind that many cars using the metal film, and while it would be great if everyone made a clear space for it somewhere on the windshield, the Tesla (and I suspect many others) don't do this. There isn't any fix for it now that it's made.

I'm not sure how your EZ-PASS system works, but one area that many others with similar issues have done is stick it inside the front bumper (which is plastic).

eelton | 1 marzo 2013

Put it on top of the plastic rear view mirror mount, on the left side, instead of on the glass itself. The glass obscured by that mount is apparently uncoated, and the RFID signals readily pass through the plastic mount.

Mark Z | 1 marzo 2013

With CA FasTrak, the dot location is the place to try. We are lucky that the 91 Express Lanes photograph the plate and doesn't penalize if the transponder doesn't register. I called them and they expect an occasional misread, hopefully less than one a month.

My Toll Roads reads are 100%, but I am still having some missed reads on the 91. Most 91 Express Lanes usage is free for ZEV vehicles, but only if you have an 91 Express Lanes account instead of The Toll Roads account.

Next year, The Toll Roads will be adding license plate accounts. The toll cost will be higher, but no transponder is necessary.

Brian H | 1 marzo 2013

Good observation. On top of the attachment itself, not the glass, not the rear of the mirror!

CC | 1 marzo 2013


Did you make sure your Temp license plate number is registered with your EZ pass??

I had the same issue, and the rep at EZ pass told me the camera's at the toll plaza reads the license plate, and will match it to the EZ pass that it is registered to. If it is not, the EZ pass will not work. I confirmed this because I tried to use my wife's EZ pass which I know it works, and I even stick it out of the pano roof, but the toll booth said "Toll not paid, proceed". I guess this is a way to catch people who steal EZ pass.

I haven't had the chance to try the EZ pass after I registered the TEMP plate number. I hope the toll plaza will read the temp plate which is stuck to the rear hatch glass.

July10Models | 2 marzo 2013

My transponder was installed inside of the nose cone behind the plate. It doesn't work from that position. I am going to move to an area in the nose cone that is not obstructed by the license plate.

dqb | 2 marzo 2013

@eelton, have you tried this already with success? What system(s)?

bp | 2 marzo 2013

The gate to my neighborhood uses RFID - and allows us to register an EZtag to open the gate - and it has worked every time - so at least in my MS - the area at the very top of the black dotted region is clear for RFID tags.

Mark Z | 12 marzo 2013

The dot area wasn't good after all. It worked 80% of the time with The Toll Roads, but the 91 Express Lanes was only 25%.

As posted elsewhere, this location is working perfectly.

The only problem with the recessed rear hatch location is the beep sound is too far from the driver.

RobS | 12 marzo 2013

Not that this helps anyone, but I discovered that the pass system in Georgia (on GA400) reverts to checking your license plate if it can't read the transponder. After seeing that that the transponder didn't get a confirmation light going through the toll, I put the transponder in my glove compartment for storage. I'm charged the regular rate each time I go through. If only all systems were this easy!

DouglasR | 12 marzo 2013

@RobS - The GoodToGo system in Puget Sound operates that way, except they tack on a quarter. You need to register your license plate, of course.

tobys1 | 12 marzo 2013

Fastrak makes an external transponder which attaches to the top of the front license plate.

I am 3146 | 12 marzo 2013

I finally have my NJ Ezpass working. All four times I went thru a plaza on the NJ Turnpike, the transponder was read. I was also succesful in going over the Commodore Barry Bridge. The trick for NJ is one the new smaller tags. I mounted it to the plastic rear view mirror mount (as other posters have suggested) It fits perfectly and is easy to access.

DouglasR | 12 marzo 2013

@I am 3146 - could you please post a picture? Thanks.

noel.smyth | 12 marzo 2013

the first windshield i had i did place it behind the dots next to the mirror and it worked. I had the windsliend replaced (with a tesla factory shipped windshield) and now it does not work at that same spot. Will try the nose cone method next.
about it being an expensive car and having this hassle, that does not bother me a bit for a first generation car. The car is so amazing still after 2 months and 3500 miles of pure joy!

I am 3146 | 12 marzo 2013

@DouglasR...I am heading into a dinner meeting and will upload it in the morning....sorry I can't do it tonight

I am 3146 | 13 marzo 2013

Posted this on other forum...easier than trying to post again...hope it works

DouglasR | 13 marzo 2013


rrios | 13 marzo 2013

"Put it on top of the plastic rear view mirror mount, on the left side, instead of on the glass itself. The glass obscured by that mount is apparently uncoated, and the RFID signals readily pass through the plastic mount."

I tried this today here in SoCal, Orange County Fastrak, and it worked on the first go through on the 261. I had tried all other spots on the windshield and nothing worked. Thanks again eelton!

ThomasK | 13 marzo 2013

I use the black-dotted area on the windshield to the right of the mirror, but with a new fastrak thing, and now it works.

DouglasR | 13 marzo 2013

In Washington, the Good-to-Go pass is the shape of a popsicle stick, and is too long to attach comfortably to the mirror mount. I'm wondering whether it might work on top of the rear view mirror itself, somewhat away from the glass. I'm crossing the bridge tomorrow, so I'll give it a try.

kalel65 | 14 marzo 2013

I have my old (the big one)NY EZ pass on the windshield on the driver's side of the rear view mirror which is where the delivery guy said to put it. When I called EZ Pass yesterday they said they were reading it without a problem.

DouglasR | 14 marzo 2013

It worked! The "popsicle stick" Good-to-Go pass is the same length and width as the top of the rear view mirror. I just stuck it there with a piece of scotch tape, and it was read both directions on the 520 bridge across Lake Washington.

Mark Z | 14 marzo 2013

The 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."

andrea.elwork | 31 marzo 2013

Problem soved! I finally got an EZ-Pass transmitter designed for front plates and it is truly easy. I installed it uderneath the front cone . I tried everything else - only this works every time. Save yourself time and just do the same.

hiroshiy | 5 aprile 2013

Glad I found this thread! Very useful information. I'm still on a waiting list in Japan (late 2013 delivery). Here in Japan automatic toll payment system is very common as in the U.S. but there's one big difference; here, the toll gates have bars and they don't open when you're not authenticated :-) I'll be extra-careful when going through them for the first several times once I get the car delivered.

warton4 | 29 febbraio 2016

I stuck mine (Texas NTTA Toll sticker Tag) on the Sunroof at the front in the middle. No issues there and not on the front Windshield

JPPTM | 1 marzo 2016

FWIW, in NoCA, if you have the white HOV stickers on your S, and you have a FasTrak Flex, you leave the 3 position switch set to '3' all of the time, whether on toll roads, HOV lanes, bridges, etc. That said, the FasTrak Flex (what it is called in NoCA) is not water resistant and did not work well under my nosecone (where I previously had the 'non switched' external license plate version). I was able to mount the Flex to the right of my rear view mirror in the black speckled area on my May 2013 S85, with the unit turned into 'portrait' orientation. As far as my wife's June 2015 S70D, without the specked area, there was no location on the inside front windshield where the Flex would work. I finally mounted it at the bottom center of the rear lift gate window (hidden by the high center setback from view in the rearview mirror).
YMMV. | 1 marzo 2016

Wonder why this ancient thread was resurrected. Florida Sunpass sent me a transponder when I applied and paid online. The document with the transponder noted that it would not work in a Model S. I called and asked why they sent it to me, if it wouldn't work. The person said that it was because I applied online. The form I filled out included the make/model of my car. Duh. I decided to attach its suction cups to my windshield anyway, just to the right of he rear view mirror. It doesn't work as advertised but they have a camera that reads my rear license plate and I get bill appropriately.

EVRider | 1 marzo 2016

@georgehawley: When they bill you after reading your plate, don't you pay more than you would pay with the transponder? It would be nice if SunPass customers paid the same tolls whether or not the transponder is used. Actually, it would be nice if every state did something like that, then we wouldn't need threads like this. :-)

PS: Old threads like this get resurrected when people actually use the search tools we recommend rather than starting new threads all the time. If the old threads are still relevant, I think that's better than starting new ones.