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Comment by chaboud | Hacker News Reader

This is a classic application of the mean value theorem. Because your position is a differentiable function, you must, at some point, have been going your average speed over a window of time, and you can be ticketed accordingly.

It's interesting to me that Fastrak transponders (electronic toll tags in the Bay Area) in express lanes aren't used to automatically generate tickets given the same understanding.

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If tickets were regularly given out in this way I think it would lead to even worse driving behavior. Sometimes I find myself going 10mph over the speed limit because that is the rate that traffic is going. If I knew that there was some MVT ticketing checkpoint coming up, I might be inclined to suddenly slow way down, stop, pull over, or otherwise freak out.

The data could be used to generate and mail warning tickets to the registered owner of the vehicle, in cases of egregious/reckless mean or a pattern of high speed trips.

Whatever that magic “bad” number is could be derived from crunching one or more of their massive data sets on tolls, driver history, violations, traffic volume, crashes with injuries, etc.

It could be combined with data from a radar camera at the toll reader to verify the license plate for the transponder account, and identify the owner who is nominally responsible.

In some cases where a family/friend is using someone else’s car to drive at highly excessive speeds over multiple trips, the vehicle owner is not aware and may like very much to know!

I don’t see how using transponder data in that way is any more or less Orwellian than speed cameras or redlight cameras. In my US city these levy actual, cumulative $100+ fines on the car’s owner.

These are “non-moving” violations, so the only impact on driving privileges is from failure to pay the fine.

That's exactly what this sort of enforcement avoids: You're averaging across multiple transponders, so unlike a cop with a LIDAR gun taking a single reading (where people do already suddenly slow down) you'd need to consistently not speed across every single one you pass.

In some areas there are several transponders less than a mile apart, so unless you plan on slamming your brakes every few thousand feet you're better off just not speeding

I'm someone who chronically speeds, but I'm also for blanket highway speed enforcement. Right now speeding seems to be about what you can get away with in a really frustrating way: If can learn the right speed traps, or you can chat a cop the right way, or your car even looks a certain way, you can get away with some ridiculous things.

Blanket enforcement wouldn't necessarily be regressive either: Regardless of how many tickets you can afford, eventually points stack up and you lose your license

> It's interesting to me that Fastrak transponders (electronic toll tags in the Bay Area) in express lanes aren't used to automatically generate tickets given the same understanding.

This would be the best imaginable way to generate a legion of single issue voters leading to an election day apocalypse for the people who implemented such an idea.

It's interesting how many laws need to be selectively enforced because consistent enforcement would enrage people.

"Average Speed Check" cameras are widely used in Britain, mostly on motorways. They are always well signed, and they are very effective at reducing speed.

At first, they were used in construction areas, which was probably acceptable to most people. I rarely drive there, so I'm not sure how much they've spread.

https://en.wikipedia.org/wiki/SPECS_(speed_camera)

Fastrak: they would fight it tooth and nail, of course. It's against their economic interest to force a ticket on their customers.

You mean the Department of Transportation that administers Fastrak (and also the CHP), the individual toll agencies, or the contractors that do various aspects of administration like billing and customer service?

At least some of them do have a positive interest in traffic enforcement beyond tolls.

Considering the revenue incentive behind express lanes, this is likely the reason. The most salesworthy point of buying your way into that lane is so you can go faster than the flow of traffic. Capping that at the speed limit is the same as capping the marginal utility.

That said, I use the lanes regularly on my motorcycle, and I've witnessed triple-digit speeds (estimated, as I would never violate the law so egregiously) from vehicles in those lanes. At some point, license plate readers and toll tags tell a tale of recklessly high speed.

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