Speed enforcement has been extensively studied, and there are a lot of publicly available articles on the subject. The results are basically universally in favour of speed enforcement reducing motor vehicle collisions, reducing injury and cost.
> The results are basically universally in favour of speed enforcement reducing motor vehicle collisions, reducing injury and cost.
Yeah this argument comes up a lot in the UK from people advocating 20mph speed limits everywhere. It's a super dumb argument though. Obviously increasing speed is never going to decrease danger. But if "slower is safer" is the only argument for 20mph then the logical conclusion is 0mph.
Clearly there are other factors at play, but the 20mph people never acknowledge that for some reason...
(To be clear I'm not advocating for 30mph everywhere. I feel like 25mph is actually the best trade-off for most suburban roads.)
It is very hard to think clearly about driving too fast given both how much fun it is and the monumental amounts of money that the car industry has pumped over decades into promoting their empty road, drive fast without consequences propaganda within our societies.
However, as with tobacco, the evidence cannot be papered over forever and there are many studies that indicate they are a bad idea (tm) in urban environments. And in particular with respect to the setting of speed limits that they should be lower than many of us have been influenced to think because the rate of injury and death increases disproportionately with speed.
For instance https://www.who.int/news-room/fact-sheets/detail/road-traffi... states that a "1% increase in mean speed produces a 4% increase in the fatal crash risk and a 3% increase in the serious crash risk". And that for pedestrians "The risk of death for pedestrians hit by car fronts rises rapidly (4.5 times from 50 km/h to: 65 km/h.".
So yes, slower is safer - not in some reductio ad absurdum sense that implies '0mph', but in a public health sense where a fair and practical compromise should be sought.
To my mind, 15 - 20mph in urban areas is that compromise.
It allows practical vehicle use, while also respecting the rights of other road users - especially pedestrians and cyclists - to exist and move about without significantly elevated risk.
The idea that some people should be granted the ability to move through shared space at speeds that make them dangerous beyond anyone else simply because they're encased in a car is not just unfair - it creates noisy, dangerous, and ultimately unliveable environments.
My problem with the 20mph speed limits in the UK is that they seem to be imposed fairly randomly.
There are many cases where wide roads with good visibility and few pedestrians crossing have 20mph limits. In one egregious case I experienced recently near identical stretches of the same road (it was a main road, I think an A road, passing through a built up area) switched between 20 and 30 mph limits. If anything it created a significant distraction keeping track of the limits.
There are a number of other roads like that have 20mph limits. On the other hand narrower side roads in the same areas has 30mph limits.
My road has a 20mph limit. On the bit I live on it makes no difference - narrower, parked cars etc. means you drive very slow anyway. Further down the road is broader and clearer. I think the reason maybe to encourage people to use the bypass instead of driving through the village so it may be reasoned- although I suspect the speed bumps are more effective at doing that.
20-to-30 causes a step change in pedestrian outcomes, so no, the logical conclusion isn't 0mph. Also the average speed on 30mph roads before the changeover was around 20mph.
It improves traffic flow and reduces pollution too.
My only objection is that it's been applied in a somewhat blind way. Long sections of road with no houses and no reported accidents should probably be 30, or even 40mph.
I think we do in practice apply 0mph (i.e. banning cars) in some major cities, turning roads into pedestrian areas! 0mph happens!
It's obviously a trade between various participants, who have their own interests. 30km/h limits have had good success. If people think the number of fatalities is a problem, there's a solution waiting for you.
Speed, of course, affects not just how many accidents there are but also how bad they are. A key argument for 20mph is that collisions with pedestrians at this speed are mostly survivable. https://publications.parliament.uk/pa/cm200102/cmselect/cmtl...
But without transport significantly more people will die from other things, due to reduced access to healthcare, employment, food, etc.
In a modern society, road transport is a critical part of our life support system. Those pushing for a what they see as a car-free utopia tend to ignore this.
30 km\h limit in densely populated and heavily used by pedestrians first\last 2-5 minutes of your travel does what? Extends your travel time by 1 minute? At the same time making it nearly impossible to kill a kid, cat, dog or human in these places.
Same goes with the right of way in these places. You're in a car, you're getting where you're going much faster anyway, so you let pedestrians go first. On pedestrian crossings, and often even without them in such "last leg" places.
It's completely logical. You don't go faster in places where somebody can suddenly walk out from behind a parked car, bush, whatever. But it's a cultural thing in Scandinavia.
There was a study [0] in Paris that demonstrates a signifiant life expectancy and positive benefit/risk ratio of bicycling or commuting by public transports: the effect on physical and psychic health largely outweighs (sometimes to x30) the risk of accidents and pollution disease.
> without transport
Nobody argues to remove all cars altogether, and certainly not other forms of transport. However we certainly can rethink the millions of individual cars in each cities: does everybody needs its own 1ton vehicle to bring food back from the local supermarket? To go to work 2-20km away?
As for trucks having the same speed limit as cars in general: 1) a lot of the time there is a lower limit, 2) the truck itself has a lower max highway speed, 3) there a far fewer trucks on the road so it doesn't matter a much, 4) they are driven by professional drivers with things like electronically enforced daily driving limits, so many of the common causes of accidents are less likely.
I see that you're not from Scandinavia. Here in Denmark the weeks around the first frost are infamous for people crashing in heaps because they were too slow to get their winter tires on and drove as usual. People here generally overestimate their ability to drive in bad weather, likely because we have so much of it.
The good thing is a large fraction of accident involving frozen roads usually happen at much smaller speeds which mean they are less likely to impact injuries and death statistics than car bodywork repairs statistics.
Tell that to all the (usually Southern) Finns who seem to think that you’re supposed to drive at or above the speed limit and at too short following distances even in terrible conditions… with predictable consequences.
Since there really are no traffic jams in Finland, my experience is that the phenomenon is worse here. In more populated countries drivers must deal with sometimes occurring reduced speeds like adults, but in Finland there usually is enough space for a single driver to keep their speed at 115% of the limit, due to other drivers facilitating the selfishness. If someone does not facilitate, the speeder will get aggressive and has to find someone to blame for their (actually, his and his car’s, which has more civil rights than a leftist) misfortune.
In Germany all drivers have to accept that there isn’t enough road capacity so everyone could drive as fast as they want and the Staus cannot be blamed on the car in front of you. It’s also common to drive under the limit, in Finland 115% of the limit is the socially acceptable minimum.
I responded to the "People drive more carefully on frozen roads." part. Which was not qualified with any particular geographical context. The point is that insofar as people drive more carefully in poor conditions in absolute terms, they still drive less carefully relative to the actual difficulty of said conditions.
I am from the alps, with my share of knowledge about frozen roads. I would add to that: "People drive more carefully on frozen roads, *if they are not used to frozen roads and/or know roads are frozen.*"
For point one: In Austria I have seen (local) cars drive 30 km/h over the speed limit on the Autobahn while it was snowing at sub zero, with exactly the same (too close) breaking distance to others. In my experience for many people used to snow/ice the speed limit is still the orientation for many during ice/snow. If anything I'd expect the increase in defensive driving to be offset by the increase in accidents due to bad view, longer breaking distances, etc.
As for the second point: In Austria the second it snows or rainfall happens at subzero amadas of snow/ice clearing vehicles hit the road, yet during my lifetime I experienced black ice multiple times. To those who don't know what this is, it is a invisible layer of extremely smooth ice coating the road, which can happen of air + road temperatures and rainfall just align in the worst way possible. The resulting road is so slippy as if god had toggled off the "simulate friction"-checkbox. I remember a time where no-one could leave my village because they couldn't get up that one hill on foot. I managed to get to school by stomping through half a meter of snow next to the road and slipped 10 times on the way to the school while wittnessing multiple (minor) car crashes. I have seen such conditions happen on the Autobahn as well and the results are not
pretty.
Zero traffic casualties in a cold climate therefore has to mean absolutely lightning fast road maintenance and/or stellar information on the current road conditions and is certainly an extremely impressive feat. I can't imagine this is possible without adaptive speed limits (and rhe infrastructure that is needed to pull that off). The Finns have reason to be proud (aside from them being really nice people in my personal experience).
I am familiar with black ice hving lived a large part of my life in Switzerland. Black ice usually involve having temperatures swinging around zero + rain. It doesn't happen if you are at -10°C.
Also. Finland has a long history of maintaining both dirt roads all year and ice roads in the winter on top of body of water so I guess drivers are much more used to them. It is also a relatively flat country.
One of my principles is that we gain control of an uncontrollable environment by relinquishing control to that environment. It may not be obvious, but icy roads are an uncontrollable environment. Hence, the rally driver gains control by relinquishing control, allowing the car to have an imaginary and symbolic role in her success (all hail Michelle Mouton). Think of the best Scandinavian WRC champ. In the real world, abandoning driving is advisable for many, or if continuing to drive in obviously unsafe conditions, controlling what can be controlled by lowering speed, etc.
This may seem improvisational, as some of it is indeed. However, these control schemes may be orchestrated as well. How? By ranking tires by performance in the worst winter conditions on Tire Rack before making a choice. Do that and everyone wins.
I'm not the person you're replying to, and I have no idea what the data says about frozen roads, but it's certainly possible that two things are both true:
- There are more accidents (per active vehicle) on frozen roads
- There are fewer fatalities on frozen roads due to the lower speeds
Yes, that is a pretty fair characterization. The reasons is because most accidents happens due to inattention and over confidence, hazardous roads makes people pay more attention. A distracted person is more dangerous than a drunkard on the road.
People not used to it. On my school run some will do 20-60 depending on where along the road and how narrow and what the sight lines are. Others will just do 20-30 for the whole 10 miles.
At a couple of locations there’s morning room but lots of room to overtake (as long as nothing comes the other way), the road is nearly wide enough to have a line down the middle. Most drivers are fine but some of the 20-30 lot will swerve all over the road to try to block overtaking.
These aren’t super narrow, you can get a tractor or hgv down the whole road, and even at some passing places get one past another.
Speed enforcement has been extensively studied, and there are a lot of publicly available articles on the subject. The results are basically universally in favour of speed enforcement reducing motor vehicle collisions, reducing injury and cost.
> The results are basically universally in favour of speed enforcement reducing motor vehicle collisions, reducing injury and cost.
Yeah this argument comes up a lot in the UK from people advocating 20mph speed limits everywhere. It's a super dumb argument though. Obviously increasing speed is never going to decrease danger. But if "slower is safer" is the only argument for 20mph then the logical conclusion is 0mph.
Clearly there are other factors at play, but the 20mph people never acknowledge that for some reason...
(To be clear I'm not advocating for 30mph everywhere. I feel like 25mph is actually the best trade-off for most suburban roads.)
It is very hard to think clearly about driving too fast given both how much fun it is and the monumental amounts of money that the car industry has pumped over decades into promoting their empty road, drive fast without consequences propaganda within our societies.
However, as with tobacco, the evidence cannot be papered over forever and there are many studies that indicate they are a bad idea (tm) in urban environments. And in particular with respect to the setting of speed limits that they should be lower than many of us have been influenced to think because the rate of injury and death increases disproportionately with speed.
For instance https://www.who.int/news-room/fact-sheets/detail/road-traffi... states that a "1% increase in mean speed produces a 4% increase in the fatal crash risk and a 3% increase in the serious crash risk". And that for pedestrians "The risk of death for pedestrians hit by car fronts rises rapidly (4.5 times from 50 km/h to: 65 km/h.".
So yes, slower is safer - not in some reductio ad absurdum sense that implies '0mph', but in a public health sense where a fair and practical compromise should be sought.
To my mind, 15 - 20mph in urban areas is that compromise.
It allows practical vehicle use, while also respecting the rights of other road users - especially pedestrians and cyclists - to exist and move about without significantly elevated risk.
The idea that some people should be granted the ability to move through shared space at speeds that make them dangerous beyond anyone else simply because they're encased in a car is not just unfair - it creates noisy, dangerous, and ultimately unliveable environments.
1 reply →
My problem with the 20mph speed limits in the UK is that they seem to be imposed fairly randomly.
There are many cases where wide roads with good visibility and few pedestrians crossing have 20mph limits. In one egregious case I experienced recently near identical stretches of the same road (it was a main road, I think an A road, passing through a built up area) switched between 20 and 30 mph limits. If anything it created a significant distraction keeping track of the limits.
There are a number of other roads like that have 20mph limits. On the other hand narrower side roads in the same areas has 30mph limits.
My road has a 20mph limit. On the bit I live on it makes no difference - narrower, parked cars etc. means you drive very slow anyway. Further down the road is broader and clearer. I think the reason maybe to encourage people to use the bypass instead of driving through the village so it may be reasoned- although I suspect the speed bumps are more effective at doing that.
2 replies →
20-to-30 causes a step change in pedestrian outcomes, so no, the logical conclusion isn't 0mph. Also the average speed on 30mph roads before the changeover was around 20mph.
It improves traffic flow and reduces pollution too.
My only objection is that it's been applied in a somewhat blind way. Long sections of road with no houses and no reported accidents should probably be 30, or even 40mph.
3 replies →
I think we do in practice apply 0mph (i.e. banning cars) in some major cities, turning roads into pedestrian areas! 0mph happens!
It's obviously a trade between various participants, who have their own interests. 30km/h limits have had good success. If people think the number of fatalities is a problem, there's a solution waiting for you.
> But if "slower is safer" is the only argument for 20mph then the logical conclusion is 0mph.
Hilariously wrong. Kinetic energy is equal to mass times velocity squared divided by half. That squaring of velocity kills your argument.
1 reply →
Speed, of course, affects not just how many accidents there are but also how bad they are. A key argument for 20mph is that collisions with pedestrians at this speed are mostly survivable. https://publications.parliament.uk/pa/cm200102/cmselect/cmtl...
1 reply →
Zero MPH = zero traffic = zero road deaths.
But without transport significantly more people will die from other things, due to reduced access to healthcare, employment, food, etc.
In a modern society, road transport is a critical part of our life support system. Those pushing for a what they see as a car-free utopia tend to ignore this.
30 km\h limit in densely populated and heavily used by pedestrians first\last 2-5 minutes of your travel does what? Extends your travel time by 1 minute? At the same time making it nearly impossible to kill a kid, cat, dog or human in these places.
Same goes with the right of way in these places. You're in a car, you're getting where you're going much faster anyway, so you let pedestrians go first. On pedestrian crossings, and often even without them in such "last leg" places.
It's completely logical. You don't go faster in places where somebody can suddenly walk out from behind a parked car, bush, whatever. But it's a cultural thing in Scandinavia.
10 replies →
There was a study [0] in Paris that demonstrates a signifiant life expectancy and positive benefit/risk ratio of bicycling or commuting by public transports: the effect on physical and psychic health largely outweighs (sometimes to x30) the risk of accidents and pollution disease.
> without transport
Nobody argues to remove all cars altogether, and certainly not other forms of transport. However we certainly can rethink the millions of individual cars in each cities: does everybody needs its own 1ton vehicle to bring food back from the local supermarket? To go to work 2-20km away?
[0] (2012, french) https://www.ors-idf.org/nos-travaux/publications/les-benefic...
It's almost as if a balance could be achieved, both by reducing the number of cars and increasing the number of trains/busses.
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[flagged]
Where did anyone say that???
As for trucks having the same speed limit as cars in general: 1) a lot of the time there is a lower limit, 2) the truck itself has a lower max highway speed, 3) there a far fewer trucks on the road so it doesn't matter a much, 4) they are driven by professional drivers with things like electronically enforced daily driving limits, so many of the common causes of accidents are less likely.
9 replies →
I see that you're not from Scandinavia. Here in Denmark the weeks around the first frost are infamous for people crashing in heaps because they were too slow to get their winter tires on and drove as usual. People here generally overestimate their ability to drive in bad weather, likely because we have so much of it.
The good thing is a large fraction of accident involving frozen roads usually happen at much smaller speeds which mean they are less likely to impact injuries and death statistics than car bodywork repairs statistics.
Tell that to all the (usually Southern) Finns who seem to think that you’re supposed to drive at or above the speed limit and at too short following distances even in terrible conditions… with predictable consequences.
I think this is universal.
Since there really are no traffic jams in Finland, my experience is that the phenomenon is worse here. In more populated countries drivers must deal with sometimes occurring reduced speeds like adults, but in Finland there usually is enough space for a single driver to keep their speed at 115% of the limit, due to other drivers facilitating the selfishness. If someone does not facilitate, the speeder will get aggressive and has to find someone to blame for their (actually, his and his car’s, which has more civil rights than a leftist) misfortune.
In Germany all drivers have to accept that there isn’t enough road capacity so everyone could drive as fast as they want and the Staus cannot be blamed on the car in front of you. It’s also common to drive under the limit, in Finland 115% of the limit is the socially acceptable minimum.
[flagged]
I responded to the "People drive more carefully on frozen roads." part. Which was not qualified with any particular geographical context. The point is that insofar as people drive more carefully in poor conditions in absolute terms, they still drive less carefully relative to the actual difficulty of said conditions.
> People drive more carefully on frozen roads.
I am from the alps, with my share of knowledge about frozen roads. I would add to that: "People drive more carefully on frozen roads, *if they are not used to frozen roads and/or know roads are frozen.*"
For point one: In Austria I have seen (local) cars drive 30 km/h over the speed limit on the Autobahn while it was snowing at sub zero, with exactly the same (too close) breaking distance to others. In my experience for many people used to snow/ice the speed limit is still the orientation for many during ice/snow. If anything I'd expect the increase in defensive driving to be offset by the increase in accidents due to bad view, longer breaking distances, etc.
As for the second point: In Austria the second it snows or rainfall happens at subzero amadas of snow/ice clearing vehicles hit the road, yet during my lifetime I experienced black ice multiple times. To those who don't know what this is, it is a invisible layer of extremely smooth ice coating the road, which can happen of air + road temperatures and rainfall just align in the worst way possible. The resulting road is so slippy as if god had toggled off the "simulate friction"-checkbox. I remember a time where no-one could leave my village because they couldn't get up that one hill on foot. I managed to get to school by stomping through half a meter of snow next to the road and slipped 10 times on the way to the school while wittnessing multiple (minor) car crashes. I have seen such conditions happen on the Autobahn as well and the results are not pretty.
Zero traffic casualties in a cold climate therefore has to mean absolutely lightning fast road maintenance and/or stellar information on the current road conditions and is certainly an extremely impressive feat. I can't imagine this is possible without adaptive speed limits (and rhe infrastructure that is needed to pull that off). The Finns have reason to be proud (aside from them being really nice people in my personal experience).
I am familiar with black ice hving lived a large part of my life in Switzerland. Black ice usually involve having temperatures swinging around zero + rain. It doesn't happen if you are at -10°C.
Also. Finland has a long history of maintaining both dirt roads all year and ice roads in the winter on top of body of water so I guess drivers are much more used to them. It is also a relatively flat country.
Could we recreate these optimum safety conditions by legislating for ice-feel tires? Then everyone would be in the slippery mindset all year.
You seem to be suggesting that frozen roads paradoxically make for safer driving?
Is that a fair characterization of your comment?
If so, that's interesting.
Why?
One of my principles is that we gain control of an uncontrollable environment by relinquishing control to that environment. It may not be obvious, but icy roads are an uncontrollable environment. Hence, the rally driver gains control by relinquishing control, allowing the car to have an imaginary and symbolic role in her success (all hail Michelle Mouton). Think of the best Scandinavian WRC champ. In the real world, abandoning driving is advisable for many, or if continuing to drive in obviously unsafe conditions, controlling what can be controlled by lowering speed, etc.
This may seem improvisational, as some of it is indeed. However, these control schemes may be orchestrated as well. How? By ranking tires by performance in the worst winter conditions on Tire Rack before making a choice. Do that and everyone wins.
I'm not the person you're replying to, and I have no idea what the data says about frozen roads, but it's certainly possible that two things are both true:
- There are more accidents (per active vehicle) on frozen roads
- There are fewer fatalities on frozen roads due to the lower speeds
[flagged]
Yes, that is a pretty fair characterization. The reasons is because most accidents happens due to inattention and over confidence, hazardous roads makes people pay more attention. A distracted person is more dangerous than a drunkard on the road.
People widely believe this about stick-shift cars, too. I don't, but people do.
And narrow lanes make drivers more cautious.
People not used to it. On my school run some will do 20-60 depending on where along the road and how narrow and what the sight lines are. Others will just do 20-30 for the whole 10 miles.
At a couple of locations there’s morning room but lots of room to overtake (as long as nothing comes the other way), the road is nearly wide enough to have a line down the middle. Most drivers are fine but some of the 20-30 lot will swerve all over the road to try to block overtaking.
These aren’t super narrow, you can get a tractor or hgv down the whole road, and even at some passing places get one past another.