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Comment by stellar678 | Hacker News Reader

The real way to make people drive a certain speed - is to design a road that makes people drive that speed.

It's been a really slow process, but bit by bit we are beginning to recover from the mistake of treating the design of transportation networks as a technical engineering problem rather than a social design problem.

If you want people to drive 25mph, you have to design a 25mph road. You can't treat it like an engineering problem and include a "50% safety buffer", because then you designed a 37.5mph road and that's how fast people will drive.

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In the UK we have "average speed cameras". They are dotted along a road, and monitor cars individually by their license plate.

I would argue they make drivers far less safe, because whilst on such a road, drivers are glued to their speedometers to make sure they're not going over the limit.

Drivers should be concentrating on driving safely. Not on driving at a specific arbitrary speed.

Surely this isn't something we need to guess at, there are roads with such systems and similar roads without and those can be compared.

Also I would think the majority of cars have cruise control (the last three cars I owned were all less than £2000 second hand and all had it) - driving at a specific speed is a button press away.

> Surely this isn't something we need to guess at, there are roads with such systems and similar roads without and those can be compared.

It's mainly done for political reasons or money raising reasons rather than safety. These cameras are usually on motorways which are the safest roads to drive on. It's all just for show, it doesn't actually make us any safer.

At least in Scotland, they're predominantly used during road works (and they do vanish afterwards). I can imagine they're worried about incidents especially when there's at times only a line of cones separating cars from workers.

Or they could just, you know, use cruise control.

I almost never touch the gas pedal once I've reached the speed limit: I just turn on cruise control and focus on the road, rather than my speedometer. Makes me a far safer driver, with the added bonus of also being a law-abiding one.

I would also say Cruise control results in more dangerous driving. If you're traveling at a constant speed, things get boring FAST. It's easy to just get bored, stop paying attention and zone out.

Cruise control isn't as big a thing in the UK. We have bendy roads and drive manual cars not automatics.

My suggestion for people who find cruise control makes driving boring, disengaging, and thus more dangerous is to instead focus on other aspects of driving - perhaps unobvious ones. It's surprisingly effective.

Personally, I use cruise control very often, and the attention freed up by it I typically put toward maintaining lane position and checking my mirrors more often. It keeps the trips engaging and makes me a safer, more consistent driver.

I'm also convinced that traffic flow would be much better if people used cruise control more often. Speed variability seems to cause excessive lane changes as a driver inadvertently slows down and the cars following attempt to pass so that they don't have to slow down too.

I rarely ever use cruise control. I actually find it useful to be able to modulate the speed of the vehicle via the accelerator. I find that not using it also helps me to adjust to potential situations that may be developing ahead e.g., letting up on the accelerator to reduce speed before even having to apply the brakes). I also will speed up while passing in order to reduce the time I have to spend in the passing lane.

I don't know whether or not this is related to the use of cruise control, but I have observed many drivers using their brakes on the highway even when it's clearly not necessary. For example, they'll slow down behind a car before switching lanes instead of anticipating the traffic situation and either letting up on the accelerator before catching up to the vehicle in front of them or adjusting their speed and moving into the adjacent lane to pass.

Some of this is simply the fact that it's still the case that many cars in Europe don't have cruise control: it isn't driver perception, it's simply the car not having it. On many cars it's something still restricted to higher trim levels or an optional extra.

I'll also say that by and large my experience in the UK is on most motorways traffic is sufficiently busy that cruise control is of relatively little use: there's enough variability in the speed of the traffic in front that you can't actually stay at a constant speed and there's enough traffic that you can't just pull out to overtake.

"Lane changes" aren't really much of a thing in the UK either.

Firstly, in the UK they aren't 'equal' lanes. They are for overtaking only. Undertaking is illegal. So we don't just change lanes willy-nilly. We change lane to overtake someone, and then change back.

Secondly, only motorways and dual-carriage ways are multi-lane. Most roads are single lane.

What makes a road a 25mph road? One dangerous enough that people don't feel comfortable driving faster -- how is that a solution?

Yes, basically. You make traffic lanes narrower, with much wider shoulders that are textured to discourage use. If there are bike lanes, you separate them with rounded dividers. Trees in the center divider also help. As do curves, and bumpouts around on-street parking.

People will just drive over textured bumps, I've seen it. You need to design the road such that people will damage their vehicle if they drive dangerously (things like on street parking, concrete bollards, tall curbs etc).

Bollards 3, bozos 0. [1]

The Sidney Harbor Tunnel had a serious problem with oversized trucks getting wedged in the tunnel. Watch a truck drive past two sets of giant flashing overhead warning signs. They stop only when they reach the final sign at the tunnel mouth, a water curtain with a giant STOP sign projected on it.[2]

[1] https://www.youtube.com/watch?v=i_Cw0QJU8ro [2] https://www.youtube.com/watch?v=pRKA7m-tbqM

That water screen is really brilliant.

An earlier bridge for them to crash into will also do the job quite nicely.

To be nice make it out of crumpling noisy material, not concrete.

> An earlier bridge for them to crash into will also do the job quite nicely.

Except for the part where it requires significantly more maintenance to fix up the bridge and it's incredibly dangerous for drivers following, whether the truck hard-stops or gets its top sheared off.

Hanging bars seem to solve this problem. Makes a loud terrifying noise when you hit them, but doesn't leave any permanent damage.

Truckers may not notice if the problem is at the rear trailer, as it was in the video. The water curtain, although unusual, is not expensive. It's just a sprinkler pipe and a very bright slide projector.

Also, it's at the start of a blind curve -- the road design naturally leads you to slow down as you approach, so stopping short be won't be as much of a problem.

Those are good points. Bollards, tall curbs, etc are appropriate for urban streets, because they protect pedestrians on sidewalks. But curbs are hazardous to bicyclists. More generally, you want streets that seem more dangerous than they actually are.

"seems more dangerous" probably only works for so long... Surely people would get used to the "dangerous" streets and realize they aren't as dangerous as they seem.

> But curbs are hazardous to bicyclists.

You can easily cut a bypass through the curb or chicane.

True. I've gone down hard, though. At night, they can be hard to see.

In neighborhoods near me we have gently sloping curbs. They are about a foot wider than the normal 90 degree curbs I see in more dense urban areas. It is easy to notice from the car if you pull partially up onto them. I suspect it also makes it slightly easier for cars to go of the road, but that hasn't been a real problem. Cars, bike and people seem to be at less risk from the curb directly.

You could think this way: When you are driving at day on a parking lot full of cars you drive slowly, right? And when you drive on a empty highway you drive fast. Regardless of law or street signals, you would drive at this same speed, right? Why? Because the environment are different. This is the point of the article. We have been giving tickets since forever and yet nothing has really changed, and nothing will change, unless we started to design the roads with the speed they need to have.

Yes but I don't see how making every road as safe to drive in as a parking lot (i.e. not very safe) vs. a big empty highway is a solution. The problem we're trying to solve is safety, not speed. Slowing people down by making roads less safe misses the point.

Traffic calming doesn't make roads less safe.

Advocates of traffic calming measures aren't trying to literally make roads as unsafe as parking lots. What makes parking lots unsafe is the constant threat of someone pulling out in front of you, no one is advocating simulating that.

Think about roundabouts, they force you to slow down because they prevent you from driving directly though an intersection. They are statistically much safer than 4 way stops.

> Traffic calming doesn't make roads less safe.

It absolutely does when you measure it against the alternatives instead of the status quo.

The only way you can get an apparent benefit from it is through people overcompensating for danger. People are driving 30MPH, you add some danger, people overcompensate for the danger by driving 25MPH, so the result is as though people were driving 28MPH on the original road. You call this a benefit.

The problem is that it's crazy. You're designing an intentional safety reduction and paying the full cost of it just so that people will overcompensate for it.

What you should be doing is designing a safety improvement that people will undercompensate for. Make the road as safe to drive at 35MPH as it was at 30MPH, but don't make that fact obvious, so that people only drive 2MPH faster even though the road is 5MPH safer. Then people drive 32MPH and the safety level is as though they were driving 27MPH on the original road. Compared to traffic calming you have a safer road and people get where they're going 7MPH faster.

Traffic calming isn't decreasing the safety of a road, it's decreasing the perceived safety of driving at higher speeds.

>Make the road as safe to drive at 35MPH as it was at 30MPH, but don't make that fact obvious

What would that even look like? What would you do to increase the safe speed of road? You'd widen the lanes, limit access etc... All of these things are antithetical to making a road safer for non-motorists.

> Traffic calming isn't decreasing the safety of a road, it's decreasing the perceived safety of driving at higher speeds.

It is decreasing the actual safety of driving at higher speeds. And at lower speeds for that matter. The hope is that people will overcompensate for the danger, so that the safety improvement from driving at lower speed is more than the safety loss from the inherently dangerous design. That is obviously not a desirable trade-off, even when that actually happens.

> What would that even look like? What would you do to increase the safe speed of road? You'd widen the lanes, limit access etc... All of these things are antithetical to making a road safer for non-motorists.

You separate the motorists from the non-motorists. Put sidewalks and bike lanes on the opposite side of each building from the road, so that a building has motorist access on the north and east and non-motorist access on the south and west. Then the building to the north has motorist access on the south and pedestrian access on the north etc.

Build pedestrian tunnels or bridges at busy intersections so that pedestrians and cyclists are never in the road at all.

Houston has a system of underground pedestrian tunnels: https://en.wikipedia.org/wiki/Houston_tunnel_system

None of those pedestrians has ever been hit by a car at any speed.

Safer for drivers - maybe. Safer for pedestrians? No.

>Think about roundabouts, they force you to slow down because they prevent you from driving directly though an intersection. They are statistically much safer than 4 way stops.

That's not entirely true, with half decent vision I can drive straight onto and off the roundabout again. Certainly in a 30/40mph limit I don't have to slow down particularly. The point of roundabouts isn't to slow people down, it's to keep traffic moving efficiently and safely.

Four way stops are just obviously an awful solution that I've never understood

The second benefit of well-made roundabouts is that they impede head-on and T-bone collisions. All accidents become side-by-side accidents.

Depends on the size of the roundabout, some are designed for 40 mph others for a more sane 20 mph.

I mean, a roundabout is a system for efficient "giving way". 20mph is only "more sane" when a roundabout is in a low speed limit area. We've got plenty of them on 60mph zones - you've got no interest in having cars slow down and accelerate again when not necessary (if nothing else because it's a waste of energy as well as time).

How is it efficient for "giving way"? If one entry is highly traficated, entries between the traficated one and the popular exits cannot get in.

By god, I hate roundabouts. Not because I have to slow down. If your exit is 45-90 degrees to the right (which a few of the roundabouts I have to go through are), you can commonly go in a straight line towards it without slowing down the slightest anyway, and going in as straight a line as possible is encouraged over here to make your intentions clear.

However, I feel much less safe going through a traficated, small-radius two-lane roundabout than I do going through a traficated intersection (making a turn or not). First of all, you have to find a gap, which is stressful and entirely unnecessary in a normal intersection. Traffic usually mean that just don't get a large enough gap to get in without accelerating hard, which isn't really safe. If you want an exit that is not the first (sometimes also the second), you have to use the inner lane, meaning that you need to find a gap in two lanes, rather than one. It seriously lacks some fair scheduling.

Depending on the roundabout, exiting can only be done by going "LEEROY JEENKIIIINS". Your mirrors point at nothing useful due to the turn of the roundabout, so the lane change back out involves going fast forward to the left, with your neck twisted as far as you can back to the right. Everyone is moving at their own random, highly variable pace, so a quick orientation is immediately invalidated. On a straight road, you can rely almost entirely on your mirrors so your peripheral vision still covers what's ahead of you.

Collisions between cars are likely milder, as the vehicle velocity is limited by the roundabout geometry, but side collisions are awful, and the chance of collision seems much higher, feeling like a game of Russian roulette. I'm normally (over)confident behind the wheel, with no problem driving like an idiot, around other driving like idiots, and have several hundred thousand kilometers of driving experience, but I get uncomfortable and stressed in those roundabouts.

Some two-lane roundabouts have fixed this by drawing the lines so that the lanes spiral out, with the outer lane going to the next exit, and the inner lane going to the one after it. In this way, going around the roundabout is a constant lane change to the left with no one beside you, and an exit is simply keeping your lane. This helps a lot, but is by no means common. Entry still sucks, though

>Collisions between cars are likely milder, as the vehicle velocity is limited by the roundabout geometry, but side collisions are awful, and the chance of collision seems much higher,

One study of 17 intersections found an 84% reduction in injury accidents. And a 100% reduction in fatal accidents. And every study I've seen is pretty similar in terms of injuries avoided.

Hmm. Those seem like very solid numbers. I wonder how the total accident count compares. Scratched cars are of course not important in comparison to a human life, but I'm curious whether my gut feeling of not being able to obtain an appropriate overview actually translate to accidents.

Fatal traffic injuries are quite rare over here (175 in 2015, which gives about 1/4th of the fatal injuries in traffic per capita of USA), with most seemingly being bicycles killed in intersections by trucks turning right in the city (We have far more bicycles than cars, and they seem to enjoy ignoring rules while simultaneously going "I HAVE THE RIGHT OF WAY AND PRIORITY OVER MOTORISED VEHICLES, SO I SHALL PROCEED BLINDLY").

I might be underestimating the intersection problem as a result of our "gentler" traffic (I don't recall ever actually seeing an intersection incident - I mostly see two-car incidents on the highway, where some idiot is too busy on their phone to see that the car in front is braking).

I agree that neighborhood roads should have roundabouts and so on. But that doesn't apply to major arteries, highways, etc.

I would agree, but my father used to drive a bottled water delivery truck. And he's seen lots of neighborhoods where roundabouts are simply not built large enough to accommodate anything with more than two axles. In California, roundabouts tend to be added into new construction, but squeezed into a space that is no larger than a normal intersection.

If they're designed properly, they should be low, almost the same height as speed bumps. That way something with 16 wheels can go straight over them while regular cars will probably go around them.

A neckdown or narrow lanes do not make a road less safe. Instead we see the opposite, traffic naturally slows down and thus the road becomes safer.

They also make the road less useful -- you have to balance safety with something. If not, it's just safer if everybody stays at home.

If the road has to close because of a traffic accident, that makes it less useful too - especially when it seems to happen almost every day. A road with less throughput that at least keeps moving can be better.

I'm a pedestrian. Many roads around me have been made more useful to you, to the point where they're useless to me. If they're all made useful, then I'll be the one who has to stay at home.

>They also make the road less useful

And that's the real goal here. This is just another avenue of attack for anti-car zealots.

You say "anti-car" like it's a bad thing.

I guess it depends on if you value freedom of movement or not.

But thanks for dropping by as an example.

I value freedom of movement - but not only through car accessibility. I value being able to walk / bike / take a bus safely and within a reasonable distance from my destination. The modern American suburb is terribly designed from this perspective.

This is not an uncommon opinion: https://likewise.am/2016/05/08/why-suburbia-sucks/

There are tricks to making roads feel smaller / trickier / slower. Search for the phrase "traffic calming" to find material on the subject.

There is a layer of perception here. People drive faster when they see lots of open space. For example, adding some barriers that obstruct sight but aren't horrible to crash into makes people drive slower without making the road much more dangerous to drive on.

Adding some trees and shrubbery between the road and the sidewalk also does a lot. Because sidewalks next to a road visually widen the road. This has the added benefit of making pedestrians feel a lot safer. No-one likes walking 2 meters next to cars driving at near-highway speeds.

>For example, adding some barriers that obstruct sight

This sounds like a recipe to increase accidents, just saying.

Experience shows they're just the opposite.

The point is not to have much of the environment hidden from sight. The point is to prevent the 'All I see is open road' feeling. On a slightly too simple note, the point is to make you feel like you need to be more careful without actually adding a lot of risk.

One might say the current road design makes roads feel so safe that the actual safety benefits get canceled out by changed behaviour.

Yes. This is a reason why a lot of one way streets are being made into 2 way streets. And why closing streets temporarily increases traffic but decreases fatalities (and eventually decreases traffic)

There is evieence that removing safety devices reduces speeds. Drivers compensate to the conditions. I found this article interesting: https://www.theguardian.com/commentisfree/2016/feb/04/remova...

Case in point: the traffic lights at the bottom of Ludgate Hill were out this morning so cars and bicyles had to negotiate the intersection without any form of communication or signalling. Nobody died.

Traffic lights are not there for safety, they are there to make cars go faster, while being dangerous for pedestrians and cyclists. People are often killed by cars turning right at traffic lights.

Well, here in Sweden the 30km/h roads are often enforced by speed bumps if the cars wouldn't slow down enough by themselves.

Here in the USA, we have speed bumps too. This is why we need to buy huge SUVs with high clearance. With a big enough vehicle, the speed bumps are not an issue. You should try it.

I often wonder what the environmental cost of speed bumps is. It is normal to drive huge SUVs. It is normal to slam on the brakes, go over the speed bump, and then hit the gas. There is also an environmental cost for broken parts that need to be replaced and oil that leaks from broken oil pans.

I bet if you combined speed bumps with a decent gas tax (with tax discounts for business use) and eliminated the "light truck" tax loophole for SUVs [1], you'd probably wipe out the huge SUV syndrome.

Of course, SUVs are highly profitable for the auto and petroleum industries, heavily represented in lobbyist circles, so it's pretty much a no-go.

[1] https://turbotax.intuit.com/tax-tools/tax-tips/Small-Busines...

> gas tax

"How to not get re-elected in the USA 101"

Combining two things Americans hate very much, gas prices and taxes.

While I generally think speed bumps are a good thing your comment made me think.

Also I like the matter-of-factly / deadpan style.

It's a solution, obviously, because people will drive the speed you want them to, 25mph, on it!

Better idea: make the road actually safe at higher speed.

If you don't want people getting hit by cars, you need to make them visible. Get rid of parallel parking. Get rid of bushes and mailboxes near the road. If there is a sidewalk, put it 10 feet from the road. Get rid of roadside advertising.

With those changes, highway speeds are perfectly safe. People don't pop out from behind opaque objects if there are no opaque objects near the road, and people don't fall into the road if the sidewalk is set back. Drivers have plenty of warning when somebody approaches the road, and there they can pay full attention because the distractions have been removed.

Giving drivers sight of pedestrians is good, but giving drivers to much open sight lines is bad. Open sight lines are exactly what make people drive faster. Mailbox near the road seem like a great idea to me. It communicates that people might be here, creates a visual obstacle that will get people to drive slower, and if you hit one, it doesn't cause a shit ton of damage (unlike, say, a tree).

As a counterpoint, having mailboxes right next to the road is a great way to wind up with your mailbox absolutely obliterated by the snowplow as it goes by...

Many ways to skin a cat. Design roads properly, sure. But I'm pretty confident that more aggressive ticketing would decrease speeding. Red light cameras certainly have that effect on red light running, and the negation just seems absurd to me. As a bonus, aggressive ticketing requires no new infrastructure.

What you propose is taking something that has essentially 0 effect on speed right now. And then doing that thing harder. Furthermore the result of not having an effect on speed but posting an authoritative sign that has little to no reflection of the actual speed has a detrimental effect on safety for pedestrians and non-automotive traffic.

There's a famous saying that goes something like this: "The definition of Insanity is doing the same thing and expecting a different result."

The article is proposing not doing the insane thing and instead doing something that studies show have the actual effect desired.

I don't think either of the following have been established:

1. We should expect existing lax enforcement to have a significant effect on speed.

2. Existing lax enforcement has a nonexistent effect compared to the baseline (no enforcement at all).

Even if you established both of these, it still wouldn't be sufficient to make the logical inference that rigorous enforcement would be ineffective for decreasing speeds. It would not be at all surprising that behavior goes unchanged if enforcement rates are below 0.1%. It would be very surprising if enforcement rates closer to 10% had no power to change behavior.

The problem is that it's really an economic problem. The existing enforcement is a revenue generation method -- everybody exceeds the speed limit, so you can put a cop anywhere who can just sit there and hand out tickets. It's net income for the government, but there isn't enough enforcement to actually change behavior.

If you added more police then people would stop speeding, but then people stop speeding -- there is no more ticket revenue. Now how are you paying for all the traffic cops?

That's an interesting technical problem. PID controllers answer a similar problem in control theory. I don't have the answer here, and I'm not certain there is one. It really depends on how many more cops we'd need to get to a state where enforcement can be rigorous, and whether we as a society prefer the tradeoff of paying for those enforcers to get safer roads. Tough question. But I like tricky questions aimed in a true direction better than easy, wrong answers like, "ticketing people has no effect on speeding."

If people were to stop speeding, perhaps there'd emerge a culture in which speeding is considered bad, reducing the need for traffic cops.

As soon as you stopped enforcing, people would speed again.

In cultures where e.g. drunk driving is considered an awful thing to do, people mostly self-regulate - there's some policing necessary, but it's not like the police are trying to stop something everyone wants to do. There's no reason it would be impossible to create a culture in which speeding is treated similarly.

There's quite a few countries in which people avoid speeding, even when there's no cameras around.

Aggressive enforcement isn't how you do that. And it's a lot harder to do it with speeding than drunk driving because it actually is a lot more dangerous to drive drunk than to drive the 85th percentile traffic speed even though the speed limit is set 10MPH lower than that.

In most of the existing places with a culture of respect for the speed limit, they have a higher speed limit.

Fair enough. The article may not have sufficiently established such a thing. But enforcement when it works is likely to only work when enforcement is frequent enough to create an expectation of getting caught. Given that this would require a significant increase in manpower to truly be effective I'm not sure it's sustainable.

I suppose you could find a way to automate it similar to red light cameras but even those have been shown to be rather ineffective at actually lowering the incidence of violations so I'm not sure anything less than the presence of a police vehicle with flashing lights that pulls up behind you would have an effect.

> But I'm pretty confident that more aggressive ticketing would decrease speeding.

It's also a good way to push people onto alternate roads which may be more dangerous or go through a neighborhood. It's also a good way to get people to completely avoid your roads and make your city or town dry up and blow away along with anybody that your roads connect.

The question is: What's the goal?

The article shows you how to increase safety.

What is your goal in busting speeders?

Where in the article is there any experimental evidence, or evidence of any kind, that increasing speed limits increases safety? They found one guy who thinks it does, which is not very convincing.

My goal in busting speeders is to increase safety. I just think the article is poorly reasoned and unconvincing in its claim that raising speed limits is an effective way to do that.

>When the speed limit is correctly set at the 85th percentile speed, the minority of drivers that do conscientiously follow speed limits are no longer driving much slower than the speed of traffic. The choice of the 85th percentile speed is a data-driven conclusion -- as noted Lt. Megge and speed limit resources like the Michigan State Police’s guide -- that has been established by the consistent findings of years of traffic studies.

>This is important because, as noted in a U.S. Department of Transportation report, “the potential for being involved in an accident is highest when traveling at speed much lower or much higher than the majority of motorists.”

And again, because everyone thinks a speed it's safe doesn't mean a speed it's safe.

People may believe it is, but phisics laws are hard to fool. Meanwhile people are well known to not understand risk and probability.

Posting speed limits that reflect actual traffic speeds decreases speed variance and decreases the frequency of crashes.

That's actually safer.

speed and severity of crashes correlation is quite established in literature, so I'm gonna wait for a study to come up with conclusive statistical data stating speed variance correlates more with injuries than absolute speed.

until then, it's conjecture, feelings and wishful thinking.

edit: then again urban and highway situations are different, so there's that. but you have truck and slow traffic on the highway anyway thus increasing car limit does increase speed variation in that situation and would be detrimental whether variance or absolute speed are considered

> speed and severity of crashes correlation is quite established in literature, so I'm gonna wait for a study to come up with conclusive statistical data stating speed variance correlates more with injuries than absolute speed.

That is if a crash happens. If you compare crash rates and fatality rates on limited access highways where speeds are higher to other types of roads, you'll find that the former is lower on both counts.

> but you have truck and slow traffic on the highway anyway

Trucks do not drive that much slower than cars unless they're going uphill or have a speed limiter. With higher speed limits, slower traffic will most likely speed up to some extent and trucking companies may remove their limiters (or increase the speed where they kick in).

Which studies? What did they show? Again, the fact that some guy claims a study shows he is right does not count for evidence.

The way to go are automated radars, that are clearly visible.

They recently installed a new radar at a local highway, right at the beginning of a speed limit.

Everyone sticks to the speed limit now.

A different section of the highway has "section control". (Cameras at the beginning and end of a section that record license plates and determine average speed). Nobody speeds there either.

With todays technology it is trivial to enforce speed limits everywhere, and people really do stick to the speed limit if they know that there are consequences.

So you like the fact that the police know exactly where and when you drove? Because the licence plate tracking cameras require that, you know.

Also, the notion that there is some universal speed limit that makes driving safe on a particular road is silly.

Two scenarios with speed limit of x: 1) sunny day, brand new porsche, new tyres. I'm driving at a sped of x+5 2) windy, snowy day, nissan sunny from the 80s with almost worn out tyres. I'm driving at x-5

Pick the safer one. I doubt anyone would think option 2 is safer, yet 1 is illegal and 2 is perfectly fine.

I see. Your'e saying: since speed limits aren't perfect in all cases, so lets not have them at all.

I do believe in increasing personal responsibility of people and having less of a nanny state, so I do tend towards that answer, but it's really not that black and white. On highways and places where pedestrians and bicyclists are not allowed - yes, no speed limit makes a lot of sense (and is available in Germany for example)

In cities and suburbs where kids can run into the street in unexpected places - more thought is needed what is the best solution.

I've actually gotten a speeding ticket because I was going 35km/h in a "construction" zone with a temporary 30km/h limit on a freaking Sunday with nobody around. That is also clearly ridiculous.

> They recently installed a new radar at a local highway, right at the beginning of a speed limit. > Everyone sticks to the speed limit now.

Has this also resulted in traffic bunching up? That is, long lines of vehicles tailgating each other?

I live near a couple of rural small-town speed traps. Yes, I have learned to set my cruise control to 45mph at the sign that is a ridiculous distance from town on otherwise normal highway to avoid tickets. The problem is, not everyone is a local, so you have people driving 45 and people trying to drive 60+ on a two lane highway with all the tailgating and reckless driving that entails. The speed trap isn't making anyone safer, it's just making those police departments richer.

Red light cameras increase accidents because people speed up if they think they are even slightly close to the limit.

Think of it this way, which changes behavior getting a ticket in 4-6 weeks by mail or having a cop pull you over today. Or worse watching someone get a ticket, or possibly noticing a flash and having no idea what it's from.

Your ideas about what red light cameras do are contradicted by the actual studies done to see what red light cameras do. https://www.fhwa.dot.gov/publications/research/safety/05048/...

Red light cameras increase rear end collisions and decrease side impact collisions; but side impact collisions are more dangerous.

The problem, of course, is that there is a better way to reduce side impact collisions -- and red light running in general -- which is to increase the length of the yellow light.

But because doing that actually does reduce the number of people who run a red light, the intersections with red light cameras do the opposite of that, because they need people to run red lights in order to generate revenue and pay for the cameras. And if you compare the results at red light camera intersections with short yellow lights against normal intersections with appropriately timed yellow lights, the cameras are killing people.

In my experience, I don't see that longer yellow lights really help much - people just keep going through until the light turns red. At least in this state, as long as you have already entered an intersection before the light turns red, you haven't run the red light.

I would think that a better strategy would be to increase the delay before turning the next light green, after the last one turned red.

> In my experience, I don't see that longer yellow lights really help much

Studies done in Virginia and Texas contradict that assertion. Increasing the yellow phase time decreased the incidence of red light running and the effect was sustained over time.

I'm interested to read a citation that shows that increasing yellow light length is superior to RLCs. Please send it my way. Thank you.

Compare the percentages for right-angle crashes on page 63 of your link to the numbers here:

http://saferstreetsla.org/wp-content/uploads/reports/A%20Com...

Assuming the number of right-angle crashes is proportional to the number of people who run red lights, the reduction due to having a longer yellow light is larger than the reduction due to the RLC. And that's before considering the rear-end collisions, which a red light camera increases but a longer yellow light reduces.

This is interesting, but it seems to mostly be focused on violations rather than crashes. I can see how the two might be related. But I also somewhat suspect that early into red violations may not be the type of red light running that causes accidents the most.

That's not what your link says, there is a modest aggregate crash cost benefit of RLC systems. It found this by: The economic analysis examined the extent to which the increase in rear end crashes negates the benefits for decreased right-angle crashes.

Rear end crashes cost less than right angle crashes. Further this does not mean there was a lower severity of crashes simply fixing doors costs more.

It examined the extent to which the rear end crashes negated the economic advantages, and found that they did not fully negate the economic advantages. They instead had an economic advantage of ~40-50k USD per site per year. See pages 5, 68, 74. This is why it's important to go further into papers than just reading the abstract.

I say they increase accidents you say, that's not true they lower costs. I say that does not mean they lower accidents. You respond yes they do, they lower cost. Do you really want me to say that's not my argument using different words?

If your point is sure they cause more accidents but that's ok because X then use that argument don't pretend there are zero costs.

PS: Economic arguments are very easy to manipulate based on what you do and do not count. So, yes I also disagree with the study, but that's not the argument I am making.

Around here red light cameras where removed. I heard it was because they where found to significantly increase accidents.

It's a complex matter. The company demands to retain control over the camera and makes the municipality pay rent if not enough tickets are issued.

Rlc issue is that incentive structure is all wrong, which lead to shortened yellows and people doing emergency braking at the slightest hint of light change.

Around here is not US and while I haven't seen anything written about such incentives I think that might be because any setup like that would be found illegal.

Your "I heard" is not a relevant response to my linked meta-analysis.

You have a constitutional right to face your accuser. Traffic cameras have got to go.

This has been covered to death on here, but your accuser is the officer of the court who signs the ticket, not the camera.

For traffic violations where a law enforcement officer initiates a traffic stop, it's clear that the officer witnessed the violation and when issuing a citation, list details such as the make and model of the vehicle, the identity of the driver, the location of the offense and what what the offense was.

If the case is taken to court, the officer will testify that he observed the vehicle committing a traffic violation (the vehicle appeared to be exceeding the speed limit), the supporting evidence of his assertion (e.g., RADAR tracking history), the fact that he initiated a traffic stop, then identified the driver, etc.

He cannot testify, under oath, that he did these things based on video or pictures that someone else took. The person that did take the video can testify to that effect though.

Has there been something more recent than this case?

http://www.thenewspaper.com/rlc/docs/2011/ca-macias.pdf

"Here, Officer Berg did not qualify as the appropriate witness and did not have the necessary knowledge of the underlying workings, maintenance, or recordkeeping of the Redflex Traffic System. The foundation for the introduction of photographical evidence and the underlying workings of the Redflex Traffic System was outside the personal knowledge of Officer Berg.

In absence of a proper foundation, the photographic evidence was held inadmissable."

The officer cannot be the accuser and introduce the evidence if he has no expertise in how the evidence was obtained.

Yes, there have been a lot of unsuccessful defenses based around the camera being your accuser, here's the first one I found.

http://caselaw.findlaw.com/ca-supreme-court/1669146.html

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