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Comment by mberning | Hacker News Reader

I find it odd that there is so much emphasis on enforcement of speed limits. Studies have shown that speed limits above and below the prevailing speed of most drivers is a much higher risk factor that raw speed. And then there are other behaviors such as using a cell phone and driving that may be criminalized, but do not seem to receive such fervent enforcement.

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Some of it is due to how easily speed can be measured but you're over-simplifying what the studies actually show. Speed is what turns minor accidents into major ones, especially for people who aren't themselves in cars[1] so while it's true that for avoiding vehicular collisions the most important factor is going around the same speed as the rest of the vehicles there's still a significant difference in injury/death rates for anything which isn't a protected highway. As a parent, I think about this a lot when I see people going 45+ MPH (>80% death rate) in the 20mph zone in front of the closest playground where a kid was killed a while back by someone who couldn't stop in time. An aggravating factor here is that drivers now are often quite distracted by touchscreen controls and phones so the window for slowing down to avoid hitting someone is even less favorable.

1. https://one.nhtsa.gov/people/injury/research/pub/hs809012.ht...

There are some newer cars with AEB that have pedestrian detection, though. You can watch videos of IIHS testing those features [0]. It's not a perfect solution but will automatically brake if a collision with a pedestrian (or other VRU) is predicted and the driver is not braking.

[0] https://youtu.be/TJgUiZgX5rE?t=109

Oh, definitely. I’d love to see those become mandatory just like seatbelts, airbags, etc. have because it’s a multi decade process to upgrade the national vehicle fleet.

That usually doesn’t kick in at higher speeds, due to the risk of it suddenly breaking on a motorway. In a way, this makes speeding even worse.

Volvo has developed "large animal" sensors that are designed to avoid collisions with moose at highway speeds. I have no idea how well they actually work in practice however.

It is simple: speeding tickets are a revenue stream.

People who break the law like to say this but I've never lived anywhere where, if that were true, the city wasn't inexplicably leaving tons of money on the table. Usually it's a token effort at addressing safety issues caused by poor road design and an excuse officers like to use to stop someone when they want to search their car.

EDIT: as a thought experiment, imagine that we went full cyberpunk hell-future and they started letting private equity companies put up cameras anywhere some MBA thought their cut of the ticket revenue would pay for the camera. How many speeding/stop sign/red light tickets do you think the average driver would get on their way to work? Now ask how different that is from the average driver's experience almost anywhere.

In Russia this is already the thing, private parties are setting their own licensed and verified speed traps.I don't know their revenue numbers, though

I don't think it's very common, but you can find places where you can plainly see that's the reason: mainly non-local tourist traffic, poor signage, no other warnings about a dangerous area or speed checks, hidden speed cameras but no police present.

This translates to: we don't care you're not going to drive here again, or that you didn't notice the sign. We don't even care if you slow down or not.

Not being sour here. I got caught at a well signed area in my local neighbourhood area - now I'm driving there slower.

In the UK it goes into central government coffers, not to police.

The fatality risk for people outside of cars (e.g. pedestrians, bicyclists, kids playing in the street) is directly correlated with speed: https://aaafoundation.org/impact-speed-pedestrians-risk-seve....

Other suggest revenue source; but I think it's simply because it's easiest to enforce and least prone to personal judgement given it's based on strict numerical limits.

Unsafe driving (braking distance, crossing lines, holding a cell phone) should be as good or even better revenue sources, but they are more difficult to enforce automatically. While nowadays there would be tech for implementing that, historically it has not been so, so the momentum of the history is perhaps making advancements slow?

There were some new cameras introduced here some time back which were advertised to be able to have quality sufficient to detect that seat belts and cell phones: but still, pictures were taken only when exceeding the speed limit, so those factors could not be used as the primary source.

not sure why this is downvoted. I have found it quite hard to find good research tying speeding to accidents. the best you get from NHTSA is accidents where speeding "was a factor". the fraction of accidents where speed was a factor is surprisingly low (around 25% IIRC), and I'm pretty sure they count speeding as a "factor" whenever someone happened to be speeding right before the incident.

I'm inclined to think speeding is enforced much more than other traffic offenses merely because it is the easiest to detect.

When allowing for a reasonable margin of error, speeding is also one of the fairer ways of enforcing traffic offenses. Anyone can be inattentive and touch a wheel to the lane line once. If it happens repeatedly, the driver is likely distracted or impaired. but one time can be a simple mistake that doesn't require intervention unless it leads to a crash or other conflict.

A driver exceeding the speed limit by 20%, to throw out a number, isn't likely to do so as a one-off mistake unless he misses a signed change in the speed limit. If exceeding by 20% was a one-off under an unchanged speed limit, it most likely means the driver was already exceeding the speed limit by 10-15% as a matter of course. I am much more comfortable with a driver being cited in this case.

right, but the question is whether speeding is actually that dangerous in the first place. it's not at all clear that absolute speed is a major contributor to the rate of accidents. we do know from physics that relative speed is a major factor in the severity of accidents, and this is supported by the empirical data. in particular, the probability of death when a pedestrian is struck increases sharply past ~20 mph.

I think we could have a much better discussion (and perhaps policy) if we distinguished more clearly between driving near pedestrians and driving on limited-access roads. I'm actually a big fan of speed cameras in cities and other dense areas, since they allow me to drive at what I consider a safe speed (at or below the posted limit) without worrying about cars flying past me at a high relative speed. on US highways, the situation is kind of absurd. I can exceed the posted limit by 50% without coming close to the limit of my car's mechanical grip. if I have a good line of sight and there's minimal traffic, why shouldn't I?

> using a cell phone and driving that may be criminalized, but do not seem to receive such fervent enforcement

It does in Germany, but then again, they regulate how much your dog is allowed to bark in Bavaria. The truth is most new cars have great phone assist, you'd be dumb to use a phone while driving otherwise and it should totally be enforced. Not criminalized, just classified as a misdemeanor.

Speed kills. It’s fairly easy to enforce as well.

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