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Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

arstechnica.com

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Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#41

Post by UnoriginalGuy »

steveax wrote: post #19
nsxwolf wrote: post #4

If the police are measuring with ultrasonic rangefinders, then cars need them too. How are human drivers supposed to judge that distance? The article makes the analogy of trying to enforce speed limits without a radar detector. Fine, but cars have speedometers that give the driver the same information. We don't demand drivers just get a feel for how fast they are going.

There are many laws like that, following too close comes to mind. If in doubt, wait to pass until you're sure you have room.

Following too close is rarely enforced, and it is a big problem. It appears like technology might help mitigate this one, radar-based systems are becoming more standard and several systems are designed to warn when you travel too close for a given speed. Additionally radar based cruise control means that even if you DO travel too close, the faster reaction of the system might avert a collision.

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#42

Post by jonahx »

rubyfan wrote: post #9

What I find more interesting than the device is a quote from the officer, "Their attitude will determine whether I issue a citation. If they take it and just throw it on the seat, then I know I wasn’t effective. Then in that case I would issue a citation." Does this seem extremely subjective and arbitrary to anyone else?

In practice, I'd think you'd see lots of false negatives (people able to feign remorse and concern well enough) but not many false positives (if you can't even be bothered to pretend to care in the face of a ticket, you probably don't).

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#43

Post by minikites »

to3m wrote: post #23
minikites wrote: post #21

Earlier quoted context omitted.

Should we treat speed limits the same way, so everyone drives around at a crawling pace?

You could do that. But most cars come with a handy dashboard-mounted speed indicator device, often in plain view of the driver - so you could use that to determine your car's speed instead.

You should, uh, read the whole thread, it's an analogy.

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#44

Post by reneherse »

plorkyeran wrote: post #7
nsxwolf wrote: post #4

If the police are measuring with ultrasonic rangefinders, then cars need them too. How are human drivers supposed to judge that distance? The article makes the analogy of trying to enforce speed limits without a radar detector. Fine, but cars have speedometers that give the driver the same information. We don't demand drivers just get a feel for how fast they are going.

As a cyclist I don't mind cars that are only two feet away, or even only one foot if they're not going that much faster than me. It'd be pretty awful to be ticketing people for only being 35" away (especially since riding in a 1" band is not feasible on most streets, so most of them wouldn't even be the car's fault), but on a lot of streets you could be pretty much continuously writing tickets for passing 6" away, an…

Close distance passing may be more tolerable for experienced and fully competent cyclists, but it's still unnecessarily risky. And the risks are much higher for those with less sure bike handling skills: new and casual riders, and the very young. It's not uncommon to see these kinds of riders wobbling back and forth, "salmoning" their way down the road, obviously lacking good situational awareness.

There are just so many reasons why it's a good idea to give cyclists a wide berth, but perhaps they all come down to this: The extra space provides a more adequate margin for error in the event of unforeseen and emergency circumstances, for both driver and cyclist.

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#45

Post by OrdaGarb »

The whole thing seems fragile, both in terms of the physical properties and legalities. Some thoughts:

Cost: $1400 for $12 worth of parts obviously hacked together in a project box seems a bit much. While not for this specific application, it's a really common project for people starting out with Arduinos: Arduino+ultrasonic sensor+display and a beeper. Usually used as a parking distance alarm in a garage. In this case the police add their own GoPro for evidence purposes I assume. Hopefully it clearly shows the position of the bicycle as well, and that he was fully to the right of the lane at the time of the measurement.

Safety: Could the possibility of a citation for uncertain margins with a bicycle cause the same nervous reactions that red light cameras cause possibly increasing the number of accidents?

Prior art: My car has an ultrasonic backup alarm with display and beeper that serves this exact purpose (measuring distance before impact). That was done in 2002, so not at all a new idea.

Value as evidence: Isn't a common defense to speeding tickets the lack of recent calibration of the RADAR gun? This thing is probably subject to all manner of interference and inaccuracies.

Countermeasures: It could be easily jammed/confused by a transmitter designed for that purpose, and that should be legal since we're talking about audio frequencies, and inaudible ones at that. Ever see those ultrasonic deer transducers that go on the bumper? They don't work for deer, but they do emit sound in the ultrasonic range at certain speeds. I could see designing one specifically as a passive jammer mounted to the right-hand mirror.

My own experiences: I've biked thousands of kilometers in the US and been hit a few dozen times, nothing very serious. Some were my fault, most the driver's fault. None were malicious, just poor observations/judgement/conditions. I ride defensively and don't really care about these laws and behave as though they don't exist since it's not wise to count on the driver, and the driver shouldn't count on me either.

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#46

Post by jonahx »

herbig wrote: post #34
sosuke wrote: post #30

How do you tell the difference between cars breaking the 3 foot rule, and cyclists breaking the 3 foot rule?

"Will this law prohibit a bicyclist from passing a car closely? No." https://bikeeastbay.org/GiveMeThree

This seems arbitrary and dangerous. A car being passed may not notice the passing cyclist in his mirrors, and attempt a lane change. Forcing the 3 foot buffer on the cyclist as well gives a chance for both cyclist and car to notice and avoid the collision.

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#47

Post by steveax »

UnoriginalGuy wrote: post #41
steveax wrote: post #19

Earlier quoted context omitted.

There are many laws like that, following too close comes to mind. If in doubt, wait to pass until you're sure you have room.

Following too close is rarely enforced, and it is a big problem. It appears like technology might help mitigate this one, radar-based systems are becoming more standard and several systems are designed to warn when you travel too close for a given speed. Additionally radar based cruise control means that even if you DO travel too close, the faster reaction of the system might avert a collision.

Yep, it's the cause of many accidents. I noticed that Tesla's new cruise control uses radar and adjusts the speed to maintain adequate distance [1]

[1]: http://arstechnica.com/cars/2015/05/review-teslas-new-model-...

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#48

Post by steveax »

rubyfan wrote: post #9

What I find more interesting than the device is a quote from the officer, "Their attitude will determine whether I issue a citation. If they take it and just throw it on the seat, then I know I wasn’t effective. Then in that case I would issue a citation." Does this seem extremely subjective and arbitrary to anyone else?

Remorse is often considered in criminal matters. I don't see how this is any different.

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#49

Post by URSpider94 »

wheaties wrote: post #13
URSpider94 wrote: post #2

California has the same law. This is a great way to get tools into the hands of police to help them enforce the law and educate drivers.

And if you decide to ride in the middle of a lane while on a bike, should the car drive in the other side of the road to pass you? This tool is arbitrary and will not change the problem, lack of dedicated bike lanes.

I agree that it would be great to have segregated bike lanes everywhere, but realistically that's not going to happen any time soon.

Re: Police use ultrasonic device to make sure drivers stay 3 feet from cyclists

#50

Post by herbig »

jonahx wrote: post #46
herbig wrote: post #34

Earlier quoted context omitted.

"Will this law prohibit a bicyclist from passing a car closely? No." https://bikeeastbay.org/GiveMeThree

This seems arbitrary and dangerous. A car being passed may not notice the passing cyclist in his mirrors, and attempt a lane change. Forcing the 3 foot buffer on the cyclist as well gives a chance for both cyclist and car to notice and avoid the collision.

Cars not noticing cyclists in their mirrors before they change lanes is the fault of the driver, not the cyclist.

Motorists should always check their mirrors before changing lanes. There could also be other cars there.

The onus is on the two ton shielded metal vehicle, not the bicycle.

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