Big Brother, here for your convenience

[jducoeur]

So we got home from Colorado this evening, arrived at Logan Airport, and went over to the parking lot. I pulled out my garage ticket, stuck it into the payment machine (they now ask you to pre-pay before going to your car), stuck in my credit card to pay, and got my receipt. Helpfully, the receipt told me which row my car was parked in, in case I had forgotten.

How the blithering heck did it know where my car was parked?

I mean, this was an anonymously-taken ticket from a week ago; they *might* infer which level I might be parked in (since it was the one they were encouraging at the time), but I parked in one of a number of open rows. Yes, I did scribble the location on my ticket, but I'd be damned impressed at any OCR software that can figure out my handwriting.

My best guess (and I'm open to simpler explanations) is that they're going through Long-Term Parking each night, recording the license plate numbers of all of the cars parked there, looking them up, and cross-referencing them with the credit card submitted for payment. (Or that they are photographing your license plate as you take your ticket when entering, and doing the cross-reference that way.) That's a non-trivial piece of engineering, but entirely feasible. But man -- that's kind of creepy, and it wouldn't even have occurred to me that they were doing it if it wasn't for that helpful line on the receipt...

Comments

[herooftheage.livejournal.com]

If you have Fastpass hooked in with your credit card, it wouldn't be too hard to have readers around the garages that noted where the transponder was.

[oakleaf-mirror.livejournal.com]

Not the likely solution, here. They'd need a large enough number of readers to cover most of the rows, and that would be expensive for an ineffective solution - the majority of cars still lack transponders.

[herooftheage.livejournal.com]

Not so many, if they have software, because of triangulation.

As for ineffective, the point would be to get people to use Fastpass, by giving them the find your car service in places like the airport, I would think.

[oakleaf-mirror.livejournal.com]

Fastpass is a ticketing system used by Disney to reduce lines at popular attractions. I'm assuming you're talking about Fast Lane, the Massachusetts name for the EZ Pass toll transponders used along the eastern seaboard states. If you're talking about something else, then the rest of this is irrelevant.

I don't suspect triangulation will work very well. Each lane at every toll plaza that reads Fast Lane transponders has it's own reader (it's the square white plate mounted at an angle, overhead). There's a sensor that tells it there's a car in the lane. The reader sends a query to your transponder, and your transponder sends it's ID back to the reader. It's normal use assumes the location of the car, and merely tries to determine if it has a transponder ID. Every time this sequence is triggered, the battery in the transponder is depleted just a little bit more. That's the main reason the transponders periodically need to be replaced - the batteries aren't user serviceable. Even assuming that they could use triangulation to figure the location of the IDs returned en mass from a query, without a check that there's a new car in the spot, the repeated queries will run down the batteries quickly, which could end up annoying the people with depleted transponders who now have to shell out another $27 for a new one.

Most people who go through toll booths with any frequency will find the convenience of having a transponder to be worth the $27 every few years. Particularly with the toll discounts in places that offer those (25 cents at the Alston and Westin tolls on the Pike, 50 cents on the Tobin bridge, that I know of). I'm always amazed at the number of people waiting in the cash line at the Alston tolls, though. I doubt a 'which row are you parked in' service would entice any of them, if the current benefits don't. And I, at least, would rather save my battery for toll booths.

[herooftheage.livejournal.com]

Wow, not how I would have designed it near a town where techie pranks are expected. You mean any decent wanna-be engineer can take a shot at depleting every transponder in town? Even if they somehow encrypt the handshaking sequence, attempting the handshaking sequence should cause the transponder to do something, thus depleting it a bit.

Really, I think I'd have included a wire to the cigarette lighter to allow for recharging, and a battery you could remove and replace yourself when it wouldn't take another recharge. Having to get another transponder when people know all about recharging tech from their cell phones seems kind of annoying.

[oakleaf-mirror.livejournal.com]

Yeah, it's not how I would have designed it, either. A wire to the cigarette lighter would be too obtrusive, I think, but a user replaceable battery would certainly be an improvement.

[queenortart.livejournal.com]

Why aren't they using RFID which doesn't need power, as the machine that's plugged into the wall in the reader sends out the bit that needs to be powered.

Duh?

[oakleaf-mirror.livejournal.com]

It's a form of RFID, but because of the circumstances of frequency, range, and speed, it needs a power source in the transponder. As to why they used what they did, I have no idea.

[keshwyn]

This would be why, whenever I'm not going someplace where I'm going to need the EZPass transponder to respond, I take the thing OFF my windshield and put it in the antistatic bag it came with in my glove compartment. Saves battery life AND means nobody's going to be pranking/BigBrothering my EZPass. :)

[jducoeur]

Good point. Do we have any idea what the security on these things is? It would be easy to design a system that had decent security on the passes, but somehow I suspect that they didn't...

[jducoeur]

I'm assuming you're talking about Fast Lane, the Massachusetts name for the EZ Pass toll transponders used along the eastern seaboard states.

True -- but he's not the only one who conflates the two names. I make that mistake fairly often (having gone through EZ Pass tolls almost as often as Fast Lane ones).

Each lane at every toll plaza that reads Fast Lane transponders has it's own reader

True, but note that that is *not* how it works down in New Jersey. Highways that have really been redesigned properly for the system (such as the Garden State) just record the thing as you drive, more or less normally, at highway speeds, and not necessarily precisely in-lane. The system doesn't actually require the slow and separated cars that we have here: that's just the way it got retrofitted into the old toll booths.

So that implies that the system can cope with at least a somewhat messier environment if you design it right.

Hadn't known about the battery issue. Dumb design, indeed...

[oakleaf-mirror.livejournal.com]

Yes, there's no reason to force the extra slow speeds that most plazas seem to want. NY is the worst offender on this, I think, at 5 MPH. The system, even as used in Massachusetts, works at highway speeds (don't ask me how I know). I've used the high speed lanes in NJ, and they do work essentially the same way. There may be a bit of lane overlap in the reader field, but it's still a query-response to a vehicle passing under it.

[jducoeur]

True -- I do have Fastpass (having made the conscious decision a few years ago that I *was* willing to trade that particular piece of privacy-for-convenience), so this seems possible.

OTOH, if this project was security-motivated (as I have to suspect it was), it seems like Fastpass penetration isn't deep enough to be appropriate for the task -- they'd want some mechanism that is more comprehensive, that will record *all* of the cars in the garage...