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.
IshKebab|7 months ago
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.)
lonelyasacloud|7 months ago
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.
graemep|7 months ago
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.
pbhjpbhj|7 months ago
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.
rtpg|7 months ago
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.
Mawr|7 months ago
Hilariously wrong. Kinetic energy is equal to mass times velocity squared divided by half. That squaring of velocity kills your argument.
gmac|7 months ago
bluescrn|7 months ago
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.
wafflemaker|7 months ago
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.
aziaziazi|7 months ago
> 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...
exe34|7 months ago
throwaway9832|7 months ago
[deleted]
franga2000|7 months ago
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.