Odometer: 1069 miles

I tried the parcel shelf mounting suggested previously on the way into Boston today, and got a 50% (i.e., 1 out of 2 reads) green light success rate, which is better than my success rate on the windshield. I’ve adjusted it again this morning for what I hope is better visibility to the transponder readers and will see what the response rate is on the way home.

For those of you suggesting holding the transponder up through the sunroof, I did try that on the way to Maine and got no response. I really do think my 12-year-old transponder batteries are at least part of my specific problem (even if the Mass EZ-Pass folks say the transponder responds just fine in their testing box).

More data when I pass through more tollbooths.

Odometer: 941 miles

A bane of a Tesla-owner’s existence is the EZ-Pass transponder.

This seemingly routine bit of hardware used to pay tolls on the practically every major toll road and bridge in the east usually just gets fastened to your windshield, and you are off to toll-booth-free nirvana. It’s typically a “5 minutes and you’re done” operation.

The above is true provided you are not a Tesla owner.

After taking my one week old S90D from Massachusetts to Maine and back, I discovered that my 11-year-old MA FastLane transponder (it predates the EZ-Pass transition) mounted in the black area of the windshield (no dots on the new windshield — you get transparent or black) was read in NH, but not in Maine.

Figuring it was the battery, I brought it to the Boston EZ-Pass office today and asked for a replacement. They tested it and said that it works fine and therefore will not replace it with a new interior transponder — only with the big black license plate one. Knowing the problems people have had with license plate mounts and autopilot hardware (my model S has that), and not having a nosecone to hide it in (I have a refreshed design model S), I’ve decided to keep my FastLane transponder and try the rear parcel shelf mounting, but given the age of the transponder and its batteries, I’m skeptical it’s going to work.

A colleague here offered a good solution that I might consider if the parcel shelf mounting doesn’t work: register with the Pennsylvania Turnpike to get one of their new interior EZ-Pass transponders. The claim is that they don’t care if your plate is from out of state, and they would give me a more modern interior transponder.

I’ll write up the results after I’ve tested the parcel shelf mounting with some Boston tollbooths.