| ▲ | gwbas1c 7 days ago |
| If anyone's still reading this: As I read this, I think it makes more sense for the police to replace radar with a high-resolution camera and a computer that can determine speed of vehicles. Any thoughts on that? |
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| ▲ | EA-3167 7 days ago | parent | next [-] |
| It's hard to find exact stats because of how procurement and statistics works across jurisdictions, states, etc... but from what I CAN find it seems that LIDAR is more common than Radar these days. Over the whole country it looks like a slight majority lead for LIDAR, but in some (quite populous) states they almost only use LIDAR (PA for example had 93% of their tickets come from LIDAR, and I believe most of the rest used speed cameras or 'clocking' rather than RADAR). Sources: https://www.legis.state.pa.us/WU01/LI/TR/Transcripts/2018_00... https://en.wikipedia.org/wiki/Lidar_traffic_enforcement https://www.ojp.gov/ncjrs/virtual-library/abstracts/lidar-sp... |
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| ▲ | toomuchtodo 7 days ago | parent [-] | | LIDAR can't be used in motion, the LEO has to be stopped to be pointing it. Your laser detector will warn you, but it's already too late at that point; my two cents is using Waze/Google LEO alerts is state of the art at this point (until someone starts multilateration of patrol cars using their radio RF emissions and SDR networks). | | |
| ▲ | bob1029 7 days ago | parent | next [-] | | > LIDAR can't be used in motion To be clear, the reason for this is because the width of the beam requires aiming it like a sniper rifle, not because we can't compensate for operator motion. | | |
| ▲ | misswaterfairy 4 days ago | parent [-] | | Most speeding offences require the use of a speed measuring device to detect and 'prove' an offence. However, a number of jurisdictions have a separate offence where 'speeding' can still be charged, including 'in motion', without lidar or radar. For example an officer following or pursuing an offender can apply a 'negligent' or 'wreckless' driving charge based in context of the officer's observations and evidence gathered, such as following or pursuing an offender well above the speed limit, observing the calibrated speedometer in the patrol car, without the use of a speed measuring device. It's been a while since I've looked at it though some Australian police forces have a calibrated speedometer installed on the dash that reads out the vehicle's speed based from the rear differential[1], separately to the vehicle's 'stock' speedometer. The reasoning, I understand, is that this is more precise, as legally the stock speedometer can display a speed up to 10 km/h lower than actual (but not above). [1] https://www.drive.com.au/news/inside-a-highway-patrol-car-th... | | |
| ▲ | barrkel 3 days ago | parent [-] | | It's the other way around: the speedo can overestimate your speed but not underestimate it. If you follow the limits with an overestimating speedo, you drive under the limit. With an underestimating speedo, you end up over. | | |
| ▲ | SoftTalker 3 days ago | parent | next [-] | | Anecdotally, when I pass those roadside speed alert signs, the speed they show and the speed on my speedometer is rarely more than +/- 1 mph. I think modern speedometers are pretty accurate, as long as the OE tire size is used. | | |
| ▲ | EA-3167 3 days ago | parent [-] | | That my experience too, the speedometer, speed my phone thinks I'm going, and static radar signs all more or less agree. Plus the only times I've been nailed for speeding, I was speeding, not "just kissing" the limit. Point being I don't think +/-1mph really matters in practice 99%+ of the time, it's usually getting tagged when being overconfident in the passing lane or something like that. |
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| ▲ | misswaterfairy 3 days ago | parent | prev [-] | | Oops, I got my words mixed up. |
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| ▲ | dreamcompiler 4 days ago | parent | prev [-] | | This is why I don't see LIDAR used much in the western US. Cops are lazy like everybody else and they'd rather fish with a net. Radar is a net. LIDAR is a speargun. It's too much work. |
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| ▲ | stefan_ 4 days ago | parent | prev | next [-] |
| Its like the dumbest product manager meme. “Humans use eyes for this right, why can’t our gadget?” “It must work at night? Oh we will just use a thermal camera” “Pixels in an image are not all from the same time instant? We will just pay 10x for a global shutter camera” The list goes on and on and on. No, they will not just be replaced by whatever is producing loose AI facsimiles of the real world in a smartphone. |
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| ▲ | adgjlsfhk1 4 days ago | parent [-] | | you can also just use a normal rolling shutter camera at a higher frame rate and blur the frames together. |
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| ▲ | netsharc 7 days ago | parent | prev | next [-] |
| It's fine... if you're fine with constant video surveillance. |
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| ▲ | gwbas1c 6 days ago | parent | next [-] | | There's a huge difference between a network of cameras on a road, versus a device that an officer has to set up and take down. | |
| ▲ | FridayoLeary 7 days ago | parent | prev [-] | | welcome to the UK. | | |
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| ▲ | SoftTalker 3 days ago | parent | prev | next [-] |
| It's been done manually for decades. Read about VASCAR[1] Yes with modern cameras and computers I would think it should be pretty doable. [1] https://en.wikipedia.org/wiki/VASCAR |
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| ▲ | foxglacier 4 days ago | parent | prev [-] |
| Average speed cameras exist and are basically that. ANPR at two locations and measure the time it took you to get between them. It's actually more fair because an occasional accidental overspeed won't get you but continuous speeding will. |
