Why speed limits don't matter

[256bits]

TL;DR Summary

Design of roads, municipal and highway, to make drivers more engaged.

This is Civil Engineering so I am posting here.
I found it quite interesting, so I am sharing.

Why speed limits don't matter

She covers road hazards alongside the roads, such a trees, poles, boulders, and why in years past a 30 foot hazard free area along side the road was thought to be the best to lower accident death and grave injury. Instead, as she explains, the open road concept, in cities, towns, rural and highway, was an ill-conceived method to lower fatal accidents, as drivers felt the need to travel faster.​

Speed limits are pretty much useless, as drivers act upon what they see down the road. Police may be able to give more tickets, but the signage does little itself for actual safety, as drivers who see a fast looking road want to drive fast, and frustrated if the signage does noy match the road.

I could carry on with what she discusses, but any synopsis by me would do the video injustice.

At the end, she list 4 objections from citizens to speed slowing methods. I do not agree entirely to her explanations, as some of the methods that have been adopted where I live, can be hazardous and confusing and frustrating, leading to drivers taking chances.

The 30 foot road clearance was expressed to a vulgar degree with the recent building of the new Champlain Bridge and access. The designers were definitely of the mindset that the wider the road the better. The access on the Montreal side seems like a mile wide, and before you know it, you are on the bridge over the water without any visual clues. Dumb as dumb can be. And to think the professionals are out there still designing and building, living and working like its 1964.

 

[Baluncore]

Non-hazardous obstacles, that will damage vehicles, should be used to mark and restrict the roadway. The presence of the obstacles gives pedestrians and cyclists somewhere safer to travel. Careless and entitled drivers, would be liable to pay more for repairs.

 

[256bits]

Non-hazardous obstacles, that will damage vehicles, should be used to mark and restrict the roadway. The presence of the obstacles gives pedestrians and cyclists somewhere safer to travel. Careless and entitled drivers, would be liable to pay more for repairs.

One example the video where a car runs up onto a ramp protecting a crosswalk.

 

[Borg]

Great video - I agree 100% with her. The town where I live has been doing exactly what she discussed on many of its high-traffic roads. They've been installing traffic circles, curb bumpouts, lumps and bumps. I've been driving those roads for years both before and after the modifications and the change in driver behavior is very noticeable. There are still a lot of dumb, distracted drivers but at least they're not going 45 in a 25.

Here's an example of a very minor change that was done in the area that clearly changed driver behavior. I drive through this T-intersection every day on the way to and from work. The sign in the middle of the intersection here is telling people to keep right. That sign got mowed down nearly every week from drivers who were cutting the corner on their left turn. The town was very active in replacing it such that I would see it down on the way to work in the morning and when I returned in the afternoon, it would be back in place. Then, they decided to install the small yellow poles around it and the hit rate dropped from once per week to around 3 or 4 times per year.

 

[Baluncore]

I prefer calming things like this, not only at tram stops, but in much greater numbers. The vehicle damage is proportional to speed, and the funniest ever is a marked police car, mounted with all four wheels off the ground.

 

[jack action]

It feels like she mixes two different things.

The observation made by Kenneth Stonex (at 2:20 in the video) called for a 30-foot clearance beside the lanes. But I never saw a sidewalk in the city 30 feet from the driving lane. Saying it doesn't work seems like comparing apples and oranges (the 30-foot clearance on highways doesn't reduce pedestrian deaths in the city !!?).

One thing not mentioned is that creating obstacle courses also creates new challenges for drivers. Of course, when entering a new setting, the driver becomes confused and slows down a lot. But drivers who are used to speed will always increase their speed more and more when they take the same road daily. The new problem is that now we are mixing extremely careful drivers - i.e., slow - with more daring drivers, which can lead to road rage from either side. They've installed a roundabout in my town, on a 90 km/h road that just encourages me to exit with the pedal to the floor. I don't floor the pedal anywhere else (anymore!).

The last thing I hate is that we pay to make the roads easier to drive, then we pay again to fill them with obstacles. It seems like a waste of work: just let the street unpaved and don't fill the holes too often to get the same effect for less money.

 

[256bits]

But I never saw a sidewalk in the city 30 feet from the driving lane

Houses in most cases are to be set back from the roadway. Besides the green grass lawn fascination, there may be some of the 30 foot aspect in municipal bylaws in play. Who likes to be the corner house on a fast street?

 

[256bits]

That sign got mowed down nearly every week from drivers who were cutting the corner on their left turn.

Yep.
"That sign just came out from nowhere officer!"

 

[256bits]

The vehicle damage is proportional to speed, and the funniest ever is a

On an expressway, a car was sitting nicely balanced on top of the median, a median 4 or so feet high. How it got up there is mysterious. Speed would have to involved, maybe from the 'kids' rushing or racing, darting in and out of lanes, in a group, to get downtown, before they turned into a pumpkin. Could have been something else, so maybe I shouldn't blame the kids, but it was a nice kid style car.
A 70 kph road, but straight and fast looking, but other cars in the way, hence the weaving in and out. Don't let me tell you that normal traffic flow speed is the posted 70; its a road tested 100kph (60mph). Doing less and one will get honked at.

 

[256bits]

The last thing I hate is that we pay to make the roads easier to drive, then we pay again to fill them with obstacles. It seems like a waste of work: just let the street unpaved and don't fill the holes too often to get the same effect for less money.

I often have the same thought.

 

[sophiecentaur]

TL;DR Summary: Design of roads, municipal and highway, to make drivers more engaged.

Speed limits are pretty much useless, as drivers act upon what they see down the road. Police may be able to give more tickets, but the signage does little itself for actual safety, as drivers who see a fast looking road want to drive fast, and frustrated if the signage does not match the road.

That video misses a huge part of the problem and the conclusions are pretty irrelevant.

It seems there is a difference between the road-using situations in US and UK. If you want to reduce deaths and serious injury in UK conditions then evidence shows that slower speeds cause fewer of both. The Kinetic Energy of any collision will be proportional to the square of the speed which is something we can't argue against. Of course, we can discuss what happens to both parties involved in a collision and whether or not both are moving but the 'square' relationship is pretty reliable. Reduced speed zones really work, however annoying to the boy (and even grandad) racers. The video above seems to be looking for largely irrelevant rules for large parts of most journeys. It's very mechanistic.

The theory that drivers take risks according to the observed conditions is reasonable enough and many drivers have a generally dangerous and competitive attitude to their driving; the video addresses them, mainly. Speed limits seem to be treated as a speed at which you should drive as near as possible rather than a speed suitable under the best conditions of the road and the driver at any time. Without education, drivers will have an unacceptable number of collisions because of this.

This is all motherhood and apple pie of course and, apart from the demands these things make on our 'fun time' they're hard to object to on the grounds of Rights.

 

[sbrothy]

I have no doubt that the future is fully automatic cars; driver-less vehicles. People will hate it. But some driver's are simply flabbergasting in their entitlement. I've had to jump for my life countless times as drivers seem to think they have the right to run people over if they're impeding their race car mentality. Along with nicotine it's a thing I wont miss. And I say that even though I myself have a driver's license and enjoy driving.

There will always be race tracks where you can risk your life for a relatively small fee.

EDIT: And I smoke and "enjoy" it.

 

[sophiecentaur]

I have no doubt that the future is fully automatic cars; driver-less vehicles. People will hate it. But some driver's are simply flabbergasting in their entitlement. I've had to jump for my life countless times as drivers seem to think they have the right to run people over if they're impeding their race car mentality. Along with nicotine it's a thing I wont miss. And I say that even though I myself have a driver's license and enjoy driving.

There will always be race tracks where you can risk your life for a relatively small fee.

I do agree with you but is there no way to regulate behaviour? The whole boy-racer thing is so strongly marketed by the auto industry that reckless or careless driving is normalised. Since my teenage years I have never understood what's so "enjoyable" about driving. It's a necessary skill of course but aren't there much more rewarding ones in life?

 

[Baluncore]

Since my teenage years I have never understood what's so "enjoyable" about driving. It's a necessary skill of course but aren't there much more rewarding ones in life?

Driving is a legal liability. Why would anyone volunteer to drive?
Is it risk-taking males, between the ages of 18 and 28, who use it as a substitute for tribal warfare, in the hope they will be seen as an alpha male by a trophy mate.

 

[sbrothy]

I do agree with you but is there no way to regulate behaviour? The whole boy-racer thing is so strongly marketed by the auto industry that reckless or careless driving is normalised. Since my teenage years I have never understood what's so "enjoyable" about driving. It's a necessary skill of course but aren't there much more rewarding ones in life?

I enjoy the freedom inherent in being able to go where I want but of course an automated vehicle can do for me too. So at it very basic it's the same joy I get out of busying my subconsciousness while my consciousness wander. A little like playing an instrument or any other skill you've trained consciously but exercise subconsciously. That doesn't mean I have to drive like an idiot though, but then again I'm not 20 anymore.

With regards to regulating the behavior I suspect that nothing short of limiting the speed is going to work, and that doesn't even eliminate the potential idiot driving behavior. There's an ongoing debate about crazy drivers here in Denmark. They keep upping the punishment, but teenagers seem to think they're immortal and just don't take the law into account when the adrenaline is pumping through their bodies.

No, I think the future is fully automated cars. There's a Danish invention called The RUF which looks promising in that regard. FYI: the word "ruf" in Danish means loosely "in a hurry". So there's some wordplay going on there. I seem to remember the system is in a test phase, but I'm in a hurry now and can't seem to find the specifics.

EDIT: Found this one:

https://www.cga.ct.gov/2003/olrdata/tra/rpt/2003-R-0579.htm

EDIT2: Looking closer I think the test phase I mentioned is rather old news. It's probably never going to get anywhere unless there's a paradigm shift. And even then....

 

[PeroK]

Where I live speed limits definitely don't matter. The whole of Westminster, London, has a blanket 20mph speed limit, but almost no one obeys it. Most vehicles drive at 30-40mph, unless slowed by congestion. After dark, many drivers go even faster.

There are speed monitors by the roadside, which continually advise drivers to slow down. No one pays any attention to these.

 

[Hornbein]

I live in Bali. Driving is anarchistic, approaching madness, but surprisingly safe. Drivers are considerate. It helps that there is a shortage of roads so speeds seldom exceed 35 mph. Most vehicles are light motorbikes without much momentum. Nevertheless I never have driven a vehicle there. I leave that to people who have been doing that their whole lives. If they've made it this far then they must be doing something right. I don't want to learn the unwritten rules the hard way. Indeed I've been told tourists are no longer going to be allowed to rent motorbikes.

I have also lived for years in Tokyo, which has remarkably little traffic. Public transportation dominates and bicycles are popular. Everyone obeys the traffic rules to the letter. However if J people think a law is foolish then they go out of their way to thumb their nose at it. I have a collection of photos of bicycles chained to "no bicycle parking" signs. They don't tolerate authoritarianism. They've had enough centuries of that.

 

[jack action]

[Moderator's note: Some content has been deleted.]

When someone who drives fast is involved in an accident, the consequences can be dramatic, but most people who drive fast don't die or have accidents.

There were big studies done locally, about 20 years ago, by the government about speeding. These were their finding:

• 51% of drivers said they were speeding in the city [1];
• 61% of drivers said they were speeding on the highway [1];
• Speeding was directly involved in 30-50% of lethal accidents and 25% of those with serious injuries [2].

sources:

1. Rapport d’étude présenté à la Société d’assurance automobile du Québec, p. 13;
2. La vitesse au volant : son impact sur la santé et des mesures pour y remédier - Synthèse des connaissances, p. III.

The point of that was to show how dangerous speeding is. But to me, it shows the opposite. If speed did not affect the accident rate, 51-61% of accidents would involve speeding drivers. If speed caused more accidents than driving slowly, then more than 51-61% of accidents would involve speeding. So, speeding drivers being involved in proportionally fewer accidents would lead to the conclusion that they are better drivers.

This correlates more with my experience, where I consider myself a more dangerous driver when I drive slowly, because I'm usually less alert to my surroundings. But if I'm driving 50 km/h over the speed limit, I can guarantee that I'm 100% focused on the road and I'm not playing with the radio.

And I'm not sure the 30-50% lethal accident rate doesn't include other causes like DUI and inexperience, both of which often come with speeding, but are, in my opinion, a greater influence in causing an accident.

 

[sbrothy]

Where I live speed limits definitely don't matter. The whole of Westminster, London, has a blanket 20mph speed limit, but almost no one obeys it. Most vehicles drive at 30-40mph, unless slowed by congestion. After dark, many drivers go even faster.

There are speed monitors by the roadside, which continually advise drivers to slow down. No one pays any attention to these.

What I meant by speed-reduction was limiting the cars' abilities to drive above a certain threshold. I know they're limited already but that's somewhere in the vicinity of 250 km/h, which is ridiculously faster than normal persons have any use for or are able to even control. Especially, if the person is an inexperienced driver or intoxicated.

 

[Averagesupernova]

Especially, if the person is an inexperienced driver or intoxicated.

Since when should the design of a vehicle be dependent on the likelihood of the driver being drunk? That is some messed up logic.

 

[sbrothy]

What is so difficult to understand about (my personal opinion that) speeds above 250 km/h being too fast for normal transportation needs especially if the driver is inexperienced or intoxicated.

You really think my logic is messed up? Is it the second part you take issue with? As I mentioned: the cars' speed is already limited. I guess the logic of the people who made that law is also messed up?

EDIT: So following your logic there should be no limit. Cars should be able to drive 500 km/h if the manufacturer thinks so?

EDIT2: I guess you have a point about the second part. I'll admit as much. That shouldn't really make a difference.

 

[Averagesupernova]

Especially, if the person is an inexperienced driver or intoxicated.

I quoted the above and then said this:

Since when should the design of a vehicle be dependent on the likelihood of the driver being drunk? That is some messed up logic.

It seems you finally made the connection on your second edit. It was my first post in this thread. Nowhere prior would any indication have been given to my opinion on speed limits. Why you would seem to form that opinion I have no idea.
-
What exactly do you mean concerning this:

I guess you have a point about the second part. I'll admit as much. That shouldn't really make a difference.

To me it implies drunk driving is acceptable.
-
I stand by my previous comment.

 

[sbrothy]

I realize my logic fallacy in the second part but stand by my opinion on the weirdness of cars being able to drive above 250 km/h for simple transportation needs (There may be a case to be made for accelerating out of a dangerous situation but then we're bordering on the academic).

Needless to say drunk driving is unacceptable and flat out despicable. I sincerely hope that nothing in my previous posts could be understood as endorsement of that.

 

[Averagesupernova]

I sincerely hope that nothing in my previous posts could be understood as endorsement of that.

I don't know how it could do anything but.

 

[sbrothy]

I kinda feel this is getting personal so I'm opting out.

 

[PeterDonis]

I don't know how it could do anything but.

I kinda feel this is getting personal so I'm opting out.

I don't think it was personal. Your post was ambiguous. You said that the driver's state of intoxication shouldn't matter. That could be taken to mean that you think people should be free to choose to drive while intoxicated.

I don't think that's what you actually meant; I think what you actually meant is that you think cars should be designed with inherent limits in how fast they can go, and those limits should not depend on the driver's state of intoxication. But what you actually said does not make that meaning clear.

 

[sbrothy]

Yes. That's it exactly. Thanks for the clarification. I'd like to blame my non-native English speaking "skills", but I'm not sure. My apologies to everyone involved. Especially @Averagesupernova


EDIT: I'd especially like to point out that I'm not inebriated.

 

[Averagesupernova]

EDIT: I'd especially like to point out that I'm not inebriated.

Lol. It had crossed my mind. With the subject matter involved here that's an easy assumption to make.

 

[Baluncore]

When someone who drives fast is involved in an accident, the consequences can be dramatic, but most people who drive fast don't die or have accidents.

Fast drivers may be safe when on the road alone, but fast drivers surprise slower drivers, because they overtake and add to the complexity faced by the slower drivers, who then further slow down, in fear of the faster drivers.

The Security Services train drivers to drive fast, so nothing can follow, or appear from behind. That way, the fast driver only needs to look forwards, while they swerve through the unsuspecting vehicles ahead.

It feels very safe to drive at 140 mph on a highway with a 70 mph speed limit. You just don't notice the trail of confusion and disruption left behind. At 140 mph you only need about 1 second to overtake a legal speed vehicle, and with good timing you can fit that in between two oncoming vehicles that are 2 seconds apart. When driving gets that simple, it is easy to convince yourself that you are an exceptionally competent driver, when in reality you are nothing but a terrorist, an anarchist on the road.

One important thing about safe driving is to maintain the smooth flow of traffic. That reduces the complexity of the forward prediction needed by others to drive safely near you. The speed limit has the effect of reducing the complexity of the driving task, by reducing overtaking. Regulations blame the following vehicle for any rear-end collision. That acknowledges the fact that drivers have two eyes in the front of their head, so can best watch where they are going. A "brake check" is a way to disturb the smooth flow of traffic, in effect, to deliberately increase the probability of accidents.

Qualified drivers should have learned to drive, in such a way that they can avoid an accident. Defensive drivers learn to avoid accidents when other drivers fail to look, or simply ignore the rules.

A speed limit should reduce overtaking and encourage the smooth flow of traffic. It really does not do that very well.

 

[sophiecentaur]

. But if I'm driving 50 km/h over the speed limit, I can guarantee that I'm 100% focused on the road and I'm not playing with the radio.

You have made several statements in a similar vein. But no, you can't guarantee that at all. F1 drivers have accidents when racing. But in their case, the conditions can be relied on to minimise danger to life or limb (but not the car). No driver can be aware of the much more complex set of possibilities in regular traffic.

Why would you drive 50mph over the limit? At best, it is anti-democratic.

 

[russ_watters]

Driving is a legal liability. Why would anyone volunteer to drive?

You're right, it's a completely pointless risk if there's alternatives that make it optional. As is the skydiving I've done once, and my pilot's license. Why indeed....

Is it risk-taking males, between the ages of 18 and 28, who use it as a substitute for tribal warfare, in the hope they will be seen as an alpha male by a trophy mate.

I think that's pushing it. For the record, I started flying lessons in earnest(minus two "discovery" flights) at age 44.

 

[Baluncore]

For the record, I started flying lessons in earnest(minus two "discovery" flights) at age 44.

All the biggest mistakes we make in life, are made in the very short period between the first and second childhood.

 

[PeterDonis]

Moderator's note: All thread participants, please refrain from comments about other people's motives or choice of language. If you see something that does not seem appropriate, use the Report button. Do not respond to it in the thread. Several posts have been either deleted or edited to remove content of that sort.

 

[jack action]

But no, you can't guarantee that at all.

Yes, I can guarantee I'm 100% focused on the road. But no, I cannot guarantee I won't have an accident ... like it is the case for any other driver.

Why would you drive 50mph over the limit?

First, I said 50 km/h; Second, in any case, pleasure.

Also, as I said in a previous post, driving below a certain speed (different for each driver in different conditions) gives you a false sense of security, your mind starts wandering out of boredom, and you are thus less alert.

At best, it is anti-democratic.

Wouldn't that imply that a democratic choice has been made at some point about what the speed limit should be? I can't even imagine what the criteria are to set one. For example, what is an acceptable death rate before we say "this is fast enough"?

What do you think about autobahns in Germany, where vehicles restricted to speeds in the range 60-100 km/h (buses, trucks, cars & motorcycles pulling trailers) share the road with vehicles driving the suggested 130 km/h, and even a few going over 250 km/h?

There is no evidence that German highway safety is much worse than anywhere else, even if you can find better somewhere else. (Although worldwide comparison can be difficult as there are many differences between countries in their geography, economy, traffic growth, highway system size, degree of urbanization and motorization, and so on.)

German organizations calling for a speed limit on autobahns often have more arguments about reducing pollution and improving traffic flow rather than road safety.

 

[jedishrfu]

When everyone follows speed limits, there is a predictability to traffic flow that reduces the chance of accidents. When some drivers break that compact, the chance of an accident increases.

In my opinion, arguing to the contrary is simply incorrect. We have many freedoms, but the freedom to speed faster than others on the road is not one of them.

One case I've observed in Houston is the desire to get on and off the freeways as quickly as possible. Some drivers will pass on the left, while others will do so on the right, or worse, hide in your blind spot. So, although you may know a car is there, it becomes very dangerous to switch to the right lane for slower traffic or to exit the freeway.

In another case, attempting to pull out onto a street with traffic moving at varying speeds is inherently dangerous without the predictability of speed limits; yet, some drivers fail to recognize the importance of these limits in regulating traffic flow. This is when traffic accidents are most likely to occur.

In any case, this is a good time to close this thread, as we have exhausted the topic to the point where our cars are worn out, and it's time to switch to walking and public transportation.

Thank you all for the stimulating conversation.

Jedi