Advocacy & Safety - Confessions of a recovering engineer

http://www.strongtowns.org/journal/2010/11/22/confessions-of-a-recovering-engineer.html

Excerpt ...

When the public and politicians tell engineers that their top priorities are safety and then cost, the engineer's brain hears something completely different. The engineer hears, "Once you set a design speed and handle the projected volume of traffic, safety is the top priority. Do what it takes to make the road safe, but do it as cheaply as you can." This is why engineers return projects with asinine "safety" features, like pedestrian bridges and tunnels that nobody will ever use, and costs that are astronomical.

An engineer designing a street or road prioritizes the world in this way, no matter how they are instructed:

1.Traffic speed
2.Traffic volume
3.Safety
4.Cost

The rest of the world generally would prioritize things differently, as follows:

1.Safety
2.Cost
3.Traffic volume
4.Traffic speed

In other words, the engineer first assumes that all traffic must travel at speed. Given that speed, all roads and streets are then designed to handle a projected volume. Once those parameters are set, only then does an engineer look at mitigating for safety and, finally, how to reduce the overall cost (which at that point is nearly always ridiculously expensive).

Is there an inverse relationship between safety and traffic speed?



The rest of the world generally would prioritize things differently, as follows:

1.Safety
2.Cost
3.Traffic volume
4.Traffic speed

I'm sure that if asked, people would prioritize safety in the abstract, but if you get them on the road I have a feeling that getting where they're going quickly would trump all other concerns. I can't think of a better way to seriously piss off drivers than this idea. (http://www.streetsblog.org/2010/11/22/vacca-endorses-life-saving-20-mph-speed-limit/) And apparently it's not clear (http://www.google.com/#sclient=psy&hl=en&safe=off&site=&source=hp&q=20mph&aq=f&aqi=h1g-s4&aql=&oq=&gs_rfai=&pbx=1&fp=3f2d83e828bdfbc) that lowering speed limits actually increases traffic safety.

And apparently it's not clear (http://www.google.com/#sclient=psy&hl=en&safe=off&site=&source=hp&q=20mph&aq=f&aqi=h1g-s4&aql=&oq=&gs_rfai=&pbx=1&fp=3f2d83e828bdfbc) that lowering speed limits actually increases traffic safety.

I have never heard of a traffic fatality who was struck at 1mph. I very much doubt that 1mph crashes are more common and more fatal than 70mph crashes. Speed plays a role.

Thanks for the post, it's interesting.

Is there an inverse relationship between safety and traffic speed?



I'm sure that if asked, people would prioritize safety in the abstract, but if you get them on the road I have a feeling that getting where they're going quickly would trump all other concerns. I can't think of a better way to seriously piss off drivers than this idea. (http://www.streetsblog.org/2010/11/22/vacca-endorses-life-saving-20-mph-speed-limit/) And apparently it's not clear (http://www.google.com/#sclient=psy&hl=en&safe=off&site=&source=hp&q=20mph&aq=f&aqi=h1g-s4&aql=&oq=&gs_rfai=&pbx=1&fp=3f2d83e828bdfbc) that lowering speed limits actually increases traffic safety.

First of all, you're a troll. This thread isn't about that at all. The article doesn't even discuss speed beyond where it ranks in the priority list. He doesn't say one necessarily comes at the cost of the other at all. And he mentions speed limits once, and with it he includes a caveat about their safety.


Second, I think you have a point buried in there. I suspect your typical person wants:
1. Safety for non-motorists where they live and play.
2. Speed for motorists where they don't.

Given people who live at any location, chosen at random, maximize both variables for all. Good luck :).

http://www.strongtowns.org/journal/2010/11/22/confessions-of-a-recovering-engineer.html

Excerpt ...

When the public and politicians tell engineers that their top priorities are safety and then cost, the engineer's brain hears something completely different. The engineer hears, "Once you set a design speed and handle the projected volume of traffic, safety is the top priority. Do what it takes to make the road safe, but do it as cheaply as you can." This is why engineers return projects with asinine "safety" features, like pedestrian bridges and tunnels that nobody will ever use, and costs that are astronomical.

An engineer designing a street or road prioritizes the world in this way, no matter how they are instructed:

1.Traffic speed
2.Traffic volume
3.Safety
4.Cost

The rest of the world generally would prioritize things differently, as follows:

1.Safety
2.Cost
3.Traffic volume
4.Traffic speed

In other words, the engineer first assumes that all traffic must travel at speed. Given that speed, all roads and streets are then designed to handle a projected volume. Once those parameters are set, only then does an engineer look at mitigating for safety and, finally, how to reduce the overall cost (which at that point is nearly always ridiculously expensive).

The proposed order of priority doesn't work. Engineering structures, of whatever nature, are intended to do something. To put safety first simply means that it would be best to have no road at all, for that would eliminate all road accidents.

There is a growing realization in the traffic engineering community that flat, wide, straight roads are not always safer in the general sense. So the situation is changing fairly rapidly.

It really seems to me that the speed limit should be self-enforcing. I.e., the speed limit should be about what people feel is appropriate for the road. I ride on residential roads that are 3 1/2 lanes wide (if nobody is parked on them, which is common) and find myself unsurprised that the traffic is going 50 in a 25 zone.

There is a growing realization in the traffic engineering community that flat, wide, straight roads are not always safer in the general sense. So the situation is changing fairly rapidly.

It really seems to me that the speed limit should be self-enforcing. I.e., the speed limit should be about what people feel is appropriate for the road. I ride on residential roads that are 3 1/2 lanes wide (if nobody is parked on them, which is common) and find myself unsurprised that the traffic is going 50 in a 25 zone.

Self-enforcing speed limits is what we have now: the actual speed limit is what the 85th percentile driver is going. My state DOT explicitly states that drivers will travel at safe speeds. Such sentiments are so contrary to the facts that I could cry. Somehow motorists that kill 40,000 and injure 4 million people per year are safe? That's just nuts. I suspect the only thing that would cause motorists to travel at safe speeds is zero-tolerance enforcement and huge consequences for infractions (loss of car, loss of license, fines of 5-10% annual income).

by self-enforcing speed limits, I mean designing roads in such a way that a motorist recognizes that they should go the speed limit. There are many ways of doing this, such as traffic tables, roundabouts, and others. Putting a road with 14 foot lanes and clear sightlines through a residential area is tantamount to telling motorists that speeding is ok, even if the speed limit is 20mph. Draconian enforcement, stop signs, and illogical speed limits have been tried and I can show you 10 roads here in State College where these methods have failed.

The only success stories of speed tables and bulb-outs in reducing speeds where I live have worked by making the route such a pain that the speeders are choosing an alternate route. It is a rob Peter to pay Paul strategy, since the city won't put them everywhere. I'm not a big fan of such measures since they seem to generally take away the line one would ride a bike in and force multiple poorly designed merge situations.

I avoid road with humps, tables and bulb outs. Too much hassle and the motorists on them are in competition for the remaining too little space left over.

Draconian enforcement, stop signs, and illogical speed limits have been tried and I can show you 10 roads here in State College where these methods have failed.I would guess because the enforcement wasn't there. There are two towns near where I grew up that had reputations of giving tickets if you went 1 mph over the limit. People would speed to the town, then they would slow down to the limit through those towns.

The proposed order of priority doesn't work. Engineering structures, of whatever nature, are intended to do something. To put safety first simply means that it would be best to have no road at all, for that would eliminate all road accidents.

I didn't take him literally since he is writing for the public. I thought of it as more as describing a weighting function (none of the parameters are zero nor infinity) in the context of a constrained optimization problem.

The only success stories of speed tables and bulb-outs in reducing speeds where I live have worked by making the route such a pain that the speeders are choosing an alternate route. It is a rob Peter to pay Paul strategy, since the city won't put them everywhere. in general, I think this is what you want. Most towns have a system of arterials and parallel neighborhood streets. If there is no penalty to go on the quieter neighborhood streets, people will speed down them. If traffic is calmed properly, then these quieter streets should be fine for cycling, leaving the arterials for motorized traffic. As it is now, typically there is a stop sign at every block in the quieter streets, which are commonly ignored by everyone and make the streets unsuitable for bicycle traffic.

Nobody has ever tried this: End prosecution of car thefts that happen on or near roads with chronic speeding problems. Tell drivers that when they behave, we'll treat auto theft like a crime again. Refuse to protect potential homicide weapons, in other words.

In a discussion about upcoming AASHTO guidelines one note was that 10' lanes are safer then 12' and have the same capacity. But stressing speed demands 12'. Side trees and street parking were also noted to slow speeds and improve safety (rarely done.) So in short we design roads so they are very tolerant of (encourage) speed over and above the posted speed limit.

Draconian enforcement, stop signs, and illogical speed limits have been tried and I can show you 10 roads here in State College where these methods have failed.

That's because it wasn't draconian. Draconian enforcement would involve very high penalties, which we don't have, for minor infractions. So speed 1mph over and we, oh let's say, take your car and sell it for state funding.

OP is spot on, except this isn't the way engineers work everywhere, just in the US and the rest of the english speaking world (UK, OZ, NZ and Canada)

The proposed order of priority doesn't work. Engineering structures, of whatever nature, are intended to do something. To put safety first simply means that it would be best to have no road at all, for that would eliminate all road accidents.

I think the priorities are supposed to be applied to a basic road structure (2-lane, 3 lane, 4 lane, shoulder/no shoulder, etc).

But you're right that some amount of traffic volume and speed has to be designed for above safety. I think the point was that even after some reasonable amount of volume is designed for, and some reasonable speed, they continue to work for more volume and speed. Sometimes they do so to lower cost, because they don't want to redesign a wider, safer and faster road but they need more volumne. Sometimes they do so simply because of congestion.

by self-enforcing speed limits, I mean designing roads in such a way that a motorist recognizes that they should go the speed limit. There are many ways of doing this, such as traffic tables, roundabouts, and others. Putting a road with 14 foot lanes and clear sightlines through a residential area is tantamount to telling motorists that speeding is ok, even if the speed limit is 20mph. Draconian enforcement, stop signs, and illogical speed limits have been tried and I can show you 10 roads here in State College where these methods have failed.

I can't remember where I first saw it, but the idea that adding extra stop signs to slow traffic down results in increases peak speeds and increased travel times. I lived in Dallas in the mid 80's, and 4 lane roads through residential areas were the norm. 50 MPH was not uncommon during rush hour on those roads, but everyone slowed down to 20 in the school zones because of the stiff fines. It took a while to get used to driving down there!

Thanks for the link.

The only thing that struck me as strange is the thought of using auto parking as traffic calming- sounds to me like keeping kids off your lawn by hiding sharp objects in the grass.

... competition for the remaining too little space left over.

This is exactly the "market" pressure that should be successful in driving people to biking or public transit. It makes me sick to see my tax money spent by the basket-full on expanding roads to make it easier to cage at higher speeds.

This is exactly the "market" pressure that should be successful in driving people to biking or public transit. It makes me sick to see my tax money spent by the basket-full on expanding roads to make it easier to cage at higher speeds.
Absolutely -- we must stop subsidizing private motor vehicle travel. If gasoline cost around $8 per gallon, to cover the full societal cost of driving, we would see more people opting for human-powered transportation and public transit.

Absolutely -- we must stop subsidizing private motor vehicle travel. If gasoline cost around $8 per gallon, to cover the full societal cost of driving, we would see more people opting for human-powered transportation and public transit.

Calculating the "full societal cost of driving" is fraught with complexities. And most arguments I have seen that attempt to use this basis also ignore the "full societal benefits of driving." In short, most of such arguments are basically anti-motoring arguments. I think that little credence should be placed on such arguments.

What exactly are 'the full societal benefits of (non-commercial/emergency) auto use'? The ability to carry a home theater system around with you at all times? Or are obesity, debt, and a daily reliance on fossil fuels 'benefits'?

When you are King just make gas $100 dollars a gallon. Maybe $1000 dollars a gallon. Put us back to the 10th century, ya that's it.

What exactly are 'the full societal benefits of (non-commercial/emergency) auto use'? The ability to carry a home theater system around with you at all times? Or are obesity, debt, and a daily reliance on fossil fuels 'benefits'?

Your rhetorical question exemplifies precisely the criticism that I made of the anti-motoring ideology. I am not going to present here a course on transportation in society. I suggest that you learn much more before you again display your ignorance so blatantly.

Calculating the "full societal cost of driving" is fraught with complexities. And most arguments I have seen that attempt to use this basis also ignore the "full societal benefits of driving." In short, most of such arguments are basically anti-motoring arguments. I think that little credence should be placed on such arguments.

I would agree, and would point out that gas prices and licensing schemes that seem Draconian by American standards have lowered the personal-motor-vehicle share in the U.K. and much of Europe, but have by no means eliminated personal motor vehicles.

There's no doubt that the current tax-and-subsidies structure in the U.S. leaves motorists subsidized by non-motorists.

Setting fuel taxes to cover the actual costs of roads, freeways, bridges, traffic signals, and emergency services dedicated to motor vehicle response would certainly mean a significant increase in gas costs, and could promote a more balanced transportation mix, but I have no doubt many personal motor vehicles would remain.

Even at $10/gallon, motor vehicles would surely be more efficient, on average, than today, but raising the gas tax well into the punitive range would not eliminate personal vehicles or recreational driving.

Humans have long placed a high value on convenient transportation. Have you ever considered the fuel and maintenance costs that people routinely undertook when personal transportation meant feeding, grooming, and caring for a horse? Or looked at the lengths people went to to find alternatives to rationed gasoline during WW II?

I would agree, and would point out that gas prices and licensing schemes that seem Draconian by American standards have lowered the personal-motor-vehicle share in the U.K. and much of Europe, but have by no means eliminated personal motor vehicles.

There's no doubt that the current tax-and-subsidies structure in the U.S. leaves motorists subsidized by non-motorists.

Setting fuel taxes to cover the actual costs of roads, freeways, bridges, traffic signals, and emergency services dedicated to motor vehicle response would certainly mean a significant increase in gas costs, and could promote a more balanced transportation mix, but I have no doubt many personal motor vehicles would remain.

Even at $10/gallon, motor vehicles would surely be more efficient, on average, than today, but raising the gas tax well into the punitive range would not eliminate personal vehicles or recreational driving.

Humans have long placed a high value on convenient transportation. Have you ever considered the fuel and maintenance costs that people routinely undertook when personal transportation meant feeding, grooming, and caring for a horse? Or looked at the lengths people went to to find alternatives to rationed gasoline during WW II?

I beg to differ. It is correct that current fuel taxes are insufficient to maintain our structure, because they are based on pre-inflation costs. Therefore, they should be raised to reflect current highway costs. But the subsidization is the reverse of what is stated above. Highway motoring taxes are taken for non motoring purposes, such as rail, and to that extent it is the motorists who are subsidizing the rest of society.

I beg to differ. It is correct that current fuel taxes are insufficient to maintain our structure, because they are based on pre-inflation costs. Therefore, they should be raised to reflect current highway costs. But the subsidization is the reverse of what is stated above. Highway motoring taxes are taken for non motoring purposes, such as rail, and to that extent it is the motorists who are subsidizing the rest of society.

Actually, it is the non-motorists who are subsidizing the motorist. Here's a link to one of many articles about this: http://www.grist.org/article/2010-09-27-why-an-additional-road-tax-for-bicyclists-would-be-unfair

This is something that should be intuitively obvious to even the most casual observer. Just look at the monstrous percentage of the public commons that are given over to cars and look at the paltry fees paid. Recent conservative estimates put the break-even gas tax at over $10/gal, and that doesn't even count the portion of the military budget that is used to maintain our drug (oil) supply. If the motoring public had to pay their own way, we would have far less driving, especially if they had to pay for all the externalities. But then, how does one fully pay for creating toxins that damage a child's I.Q.?

I'll note there is some technical differences if you are talking about just one Federal transportation program or all Federal transportation programs or all user fee based transportation programs.

You can point to one program and say oh look motoring user fees pays for mass transit but once you look beyond that and at the system as a whole, motoring no longer pays for it's self and is supplemented by more money then it gives out to non-motoring projects.

I beg to differ. It is correct that current fuel taxes are insufficient to maintain our structure, because they are based on pre-inflation costs. Therefore, they should be raised to reflect current highway costs. But the subsidization is the reverse of what is stated above. Highway motoring taxes are taken for non motoring purposes, such as rail, and to that extent it is the motorists who are subsidizing the rest of society.

Even long before this current age of inflation, highway costs were largely subsidized by general funds... the 1956 highway act for instance was largely paid out of general funds with the "excuse" being a need for national defense...

Of course this "need" was largely driven (OK pun intended) by the former president of General Motors... sure, nothing but a coincidence. :innocent:

Actually, it is the non-motorists who are subsidizing the motorist. Here's a link to one of many articles about this: http://www.grist.org/article/2010-09-27-why-an-additional-road-tax-for-bicyclists-would-be-unfair

This is something that should be intuitively obvious to even the most casual observer. Just look at the monstrous percentage of the public commons that are given over to cars and look at the paltry fees paid. Recent conservative estimates put the break-even gas tax at over $10/gal, and that doesn't even count the portion of the military budget that is used to maintain our drug (oil) supply. If the motoring public had to pay their own way, we would have far less driving, especially if they had to pay for all the externalities. But then, how does one fully pay for creating toxins that damage a child's I.Q.?

TheHen's argument is based on the theory that the urban land used for transportation has a better, higher-paid use, and that the motoring public should be charged and paying to government according to that "better, higher-paid use". So, Hen, from what reputable school of economics does that theory spring?

What exactly are 'the full societal benefits of (non-commercial/emergency) auto use'?

It isn't clear what the bounds are for commercial/emergency travel. That is, how people categorize some purpose of travel would vary.

Nonetheless, if you get from A to B faster and in a more convenient fashion, isn't that a benefit?

Some people might have few or no reasonable alternatives than the auto ... infirm/elderly/infant/toddler/disabled ... is it a benefit if they go from A to B for whatever reason?

Remember, cycling or walking entails pollution too. You have to feed your engine and you produce waste. And if you search the web, you will find (support for) that motorized transportation can be more efficient per mile than people. Especially if you allow more than one person in the vehicle.


Humans have long placed a high value on convenient transportation.

Sure. Although they design their villages/neighborhoods/cities/whatever to fit with their preferences and resources.


I beg to differ. It is correct that current fuel taxes are insufficient to maintain our structure, because they are based on pre-inflation costs. Therefore, they should be raised to reflect current highway costs. But the subsidization is the reverse of what is stated above. Highway motoring taxes are taken for non motoring purposes, such as rail, and to that extent it is the motorists who are subsidizing the rest of society.

You are right that sifting through all of the figures is tricky. Referencing another post of yours, measuring the benefits and costs is also extremely difficult since transportation is thoroughly intertwined; if I make public transportation better, motorized transport could improve as well. But it appears to be a problem worth investigation since getting some rough estimate with the understanding of what we fail to measure is probably a significant improvement over armchair speculation.


Actually, it is the non-motorists who are subsidizing the motorist. Here's a link to one of many articles about this: http://www.grist.org/article/2010-09-27-why-an-additional-road-tax-for-bicyclists-would-be-unfair

This is something that should be intuitively obvious to even the most casual observer. Just look at the monstrous percentage of the public commons that are given over to cars and look at the paltry fees paid. Recent conservative estimates put the break-even gas tax at over $10/gal, and that doesn't even count the portion of the military budget that is used to maintain our drug (oil) supply. If the motoring public had to pay their own way, we would have far less driving, especially if they had to pay for all the externalities. But then, how does one fully pay for creating toxins that damage a child's I.Q.?

$10/gallon ... really? Generally, we should avoid pushing arguments that something is intuitively obvious. Lot's of terrible things, never mind wasteful things, have been pushed forward because it was intuitively obvious.

What if dramatically raising the cost of gasoline today resulted in less children going to the doctor's office?

EDIT: Those are really back of the envelope calculations in the grist article. It doesn't hurt to do them and it helps put certain aspects into perspective; but the problem (IMO) is much bigger than that.


I'll note there is some technical differences if you are talking about just one Federal transportation program or all Federal transportation programs or all user fee based transportation programs.

You can point to one program and say oh look motoring user fees pays for mass transit but once you look beyond that and at the system as a whole, motoring no longer pays for it's self and is supplemented by more money then it gives out to non-motoring projects.

Unfortunately, I have to agree with this observation. At least for me, it has been pretty difficult disentangling all of the flows. I have some fuzzy observations and think that it is probably the case that there has been a net subsidization of drivers and roads. Although to be fair, there are lots of large price distortions regarding transportation.

Even long before this current age of inflation, highway costs were largely subsidized by general funds... the 1956 highway act for instance was largely paid out of general funds with the "excuse" being a need for national defense...

Of course this "need" was largely driven (OK pun intended) by the former president of General Motors... sure, nothing but a coincidence. :innocent:

So the initial funds for starting the Interstate Highway System came from general funds? However, since then, the system has, until recently, paid for itself out of the fuel taxes collected.

So the initial funds for starting the Interstate Highway System came from general funds? However, since then, the system has, until recently, paid for itself out of the fuel taxes collected.

And meanwhile much more freeway has been added, again by using general funds... So the system was never self supporting... as more roadway has been built over time than fuel taxes could ever support. And of course we are talking about the interstate freeway system, while avoiding the ever present "elephant in the room;" the rest of the roadway system, other than interstate freeway... the latter which has never been supported by fuel taxes, but generally funded by developer fees, and local and state general taxes.

A few minor exceptions do however exist. I believe it is Montana that has a roadway system largely supported by fuel taxes.

The other 'concern' is that while there are many good aspects of a low cost transport system, it also enables/encourages frivolous and wasteful (both by my judgment) uses that do not provide benefit. Not an easy concern to address as no one want to tell others what then can or should do - how is is possible to discourage the waste without inhibiting the good?

in general, I think this is what you want. Most towns have a system of arterials and parallel neighborhood streets. If there is no penalty to go on the quieter neighborhood streets, people will speed down them. If traffic is calmed properly, then these quieter streets should be fine for cycling, leaving the arterials for motorized traffic. As it is now, typically there is a stop sign at every block in the quieter streets, which are commonly ignored by everyone and make the streets unsuitable for bicycle traffic.

I think a lot depends on the nature of the location. I typically find driving in the US far less stressful than driving in the UK, specifically because the roads are wider and the volumes of traffic lower.

Traffic calming is a good thing in many ways although will never overcome the problem of locals using side roads as fast short-cuts. You can grow all the overhanging trees you want and introduce bends for the sake of slowing down traffic all you want but local drivers will soon learn the layout of the roads.

Where I live in suburban London (England) it is very common for residential streets to have cars parked down both sides, leaving a single lane through the middle. Meeting a car coming the other way means someone has to back up. But in spite of that people still drive far too fast, especially since parked cars in residential streets present an increased chance of a pedestrian appearing with little if any warning.

The other issue with a lot of traffic calming is that those inclined to the highest speeds (we call them boy racers in the UK) have been known to regard traffic calming as a test of their driving skill. I've seen teenagers in souped up cars apparently attempting 0-60-0 between speed bumps and have also seen similar drivers flying through chicanes and pinch points fast enough that they have visibly come very close to losing control of their car completely. If I'm on two wheels I'd rather have someone scream past in a straight line than scream past swerving side to side desperately trying to regain control.

And meanwhile much more freeway has been added, again by using general funds... So the system was never self supporting... as more roadway has been built over time than fuel taxes could ever support. And of course we are talking about the interstate freeway system, while avoiding the ever present "elephant in the room;" the rest of the roadway system, other than interstate freeway... the latter which has never been supported by fuel taxes, but generally funded by developer fees, and local and state general taxes.

A few minor exceptions do however exist. I believe it is Montana that has a roadway system largely supported by fuel taxes.

Not really, it'd be trivial to get the fuel tax high enough to pay for it all. For some reason people think they already pay more than it costs. Probably because, even with the short fall, we take a big chunk out to pay for the mass transit that is more and more necessary for people without a car as we rebuild our environment at 5 times to size to support cars. And they disagree with the idea that they should subsidize that. Like I said, even without that subsidy, they still don't pay enough. But doubling the gas tax would fix it, and that would be a smaller increase in price than we've seen from just market forces.



I think John's right that interstates easily pay for themselves. Freeways may not, and many of them are on the interstate system. But they're a different sort of beast that grew naturally out of interstates (and some of them are necessary as the city grows around a small chunk of an interstate).


Really, when you add it all up, we spend a pretty reasonable amount on roads. We could easily spend less, and probably be fine. But it's on the order of thousands per household per year for highways, local roads, side streets, etc. Probably less than we spend owning the cars we drive on those roads.

The other 'concern' is that while there are many good aspects of a low cost transport system, it also enables/encourages frivolous and wasteful (both by my judgment) uses that do not provide benefit. Not an easy concern to address as no one want to tell others what then can or should do - how is is possible to discourage the waste without inhibiting the good?

Noisebeam pontificates that some motoring is done for reasons that he does not approve. I suppose that motoring home to one's wife is an approved use, while motoring after work to one's mistress is disapproved?

The other 'concern' is that while there are many good aspects of a low cost transport system, it also enables/encourages frivolous and wasteful (both by my judgment) uses that do not provide benefit. Not an easy concern to address as no one want to tell others what then can or should do - how is is possible to discourage the waste without inhibiting the good?

Doesn't a per use tax as opposed to a per car or per fuel tax address this? That is, a tax on cars affects the number of cars but not the amount of driving after the fixed fee is paid. A gasoline tax affects the amount of fuel used which is clearly correlated with the amount of driving but also other things associated with the amount of fuel consumed. A tax on the amount of driving would most directly affect the amount of miles driven and, if it is applied in a particular way, when and where people drive.

Humans have long placed a high value on convenient transportation. Have you ever considered the fuel and maintenance costs that people routinely undertook when personal transportation meant feeding, grooming, and caring for a horse? Or looked at the lengths people went to to find alternatives to rationed gasoline during WW II?

This all seems radically off topic, but that last part sounds very interesting. Go on please :).



Setting fuel taxes to cover the actual costs of roads, freeways, bridges, traffic signals, and emergency services dedicated to motor vehicle response would certainly mean a significant increase in gas costs, and could promote a more balanced transportation mix, but I have no doubt many personal motor vehicles would remain.

I really don't agree with forcing motorists to pay full road costs. I think the mix we have now is pretty fair (they pay something like 80%). It would be interesting to, in my opinion, to investigate two additional costs accounted for:
1. Military protection for the oil supply
2. Policing and emergency services needed

Number 1 would be very very controversial. Number 2 might be how you finally convince motorists that speed cameras an red light cameras aren't the end of the bill of rights.

...how you finally convince motorists that speed cameras an red light cameras aren't the end of the bill of rights.

The big problem with speed cameras is that they measure one aspect of driver behaviour at one point in time. They have no capability to reason, they simply enforce an arbitrary number with no consideration of the context. So if the threshold is 75mph they will catch the person doing a steady 80 on an empty road in good conditions while ignoring the person doing 73 in appalling conditions who is weaving through heavy traffic and tailgating.

They also tend to encourage people to look at their speedometer rather than at the road, which isn't a particularly good way to improve road safety. I'd rather see someone driving through town at 34 watching the road than 29 watching their speedo.

Doesn't a per use tax as opposed to a per car or per fuel tax address this? That is, a tax on cars affects the number of cars but not the amount of driving after the fixed fee is paid. A gasoline tax affects the amount of fuel used which is clearly correlated with the amount of driving but also other things associated with the amount of fuel consumed. A tax on the amount of driving would most directly affect the amount of miles driven and, if it is applied in a particular way, when and where people drive.

I don't think it would have much affect. The estimates I've read imply that the societal costs of driving are maybe $.50 a mile. So even if you charged $.50 per mile in taxes I don't think you'd change people's driving habits much. That's a similar cost to what your typical motorist is already shoving into their car in insurance, gas, and vehicle costs (including interest on the loan for their chosen status symbol).

You might make an impact on their preferences about distance to location. "Drive till you qualify" would, probably, turn into a shorter distance.

You'd probably put driving out of reach for a few more people as well.


Who cares if people go for pleasure cruises anyway. Or go shopping to buy nothing. The expensive part of all this seems to be that everyone works 9-5, so everyone wants to drive across town at 8:30 and 5:00 each day... Often all in the same direction, on the same high speed facility.

And since they work, live, and shop in 3 different spots there is parking for their car in 3 different spots. Probably more if you add in the residential street parking (which some use quite a bit, and in other areas it goes mostly unused).

Noisebeam pontificates that some motoring is done for reasons that he does not approve. I suppose that motoring home to one's wife is an approved use, while motoring after work to one's mistress is disapproved?

No less "disapproved" than a peloton of cyclists using the roadway for their own entertainment on a Sunday afternoon... AND representing the majority of the road users (hence "traffic") at the time.

The big problem with speed cameras is that they measure one aspect of driver behaviour at one point in time. They have no capability to reason, they simply enforce an arbitrary number with no consideration of the context. So if the threshold is 75mph they will catch the person doing a steady 80 on an empty road in good conditions while ignoring the person doing 73 in appalling conditions who is weaving through heavy traffic and tailgating.

They also tend to encourage people to look at their speedometer rather than at the road, which isn't a particularly good way to improve road safety. I'd rather see someone driving through town at 34 watching the road than 29 watching their speedo.

Pfft, every bit of that is fixable.

1. It can easily account for the speed of traffic on average and penalize those speeding through at absurd speeds. No one cars, now, if you do 5 over. But everyone gasps when there's no cop to catch the guy doing 15-30 over. And traffic will slow for poor conditions, where the speed limit may be (reasonably speaking) speeding if everyone is doing half that. You can still capture the guy doing that.
2. You can combine data points over time trivially. It's easy to get the plate in the scan and use multiple cameras to get a picture for how they were driving in general.
3. Obsessive speedometer checking will go away as soon as drivers realize they're not getting tickets for driving how they used to.


You could probably spot tailgating with cameras as well. There's a lot of traffic enforcement that's very automatable. A speed camera doesn't have to be a super simple radar gun that also takes pictures.

Noisebeam pontificates that some motoring is done for reasons that he does not approve. I suppose that motoring home to one's wife is an approved use, while motoring after work to one's mistress is disapproved?
I carefully phrased that to say that some roadway use is wasteful/frivolous in my judgment and that addressing this goes into the uncomfortably territory of telling what others should or should not do. I am not willing and did not say my judgment is the only or correct one.
Some of that 'wasteful/frivolous' use I am thinking of includes excessive/aggressive speeding and jackrabbit starting and unnecessarily fast stopping in urban areas that I see every day. I can not judge the purpose of a trip as I can not know it, but I can judge the manner in which it is motored. With people wasting fuel every day multiple times leads be to believe it is undervalued by many.

I don't think it would have much affect. The estimates I've read imply that the societal costs of driving are maybe $.50 a mile. So even if you charged $.50 per mile in taxes I don't think you'd change people's driving habits much. That's a similar cost to what your typical motorist is already shoving into their car in insurance, gas, and vehicle costs (including interest on the loan for their chosen status symbol).

Hmmmm? Some of those are not per mile costs on the margin. That is, they generally don't vary with how much driving one does (insurance might though). You want the price on the margin to match the true cost.

Actually, I could care less if it is for pleasure or not. But the costs to society, hence why the price should vary, does change if one decides to drive during rush hour or other peak loads versus alternatives.

Generally, I think that if you want people to drive less, you should raise the price of driving. If you want people to park less, you should raise the price of parking. If you want people to use less fuel, raise the price of fuel.

I carefully phrased that to say that some roadway use is wasteful/frivolous in my judgment and that addressing this goes into the uncomfortably territory of telling what others should or should not do. I am not willing and did not say my judgment is the only or correct one.
Some of that 'wasteful/frivolous' use I am thinking of includes excessive/aggressive speeding and jackrabbit starting and unnecessarily fast stopping in urban areas that I see every day. I can not judge the purpose of a trip as I can not know it, but I can judge the manner in which it is motored. With people wasting fuel every day multiple times leads be to believe it is undervalued by many.


:D Yup, until they have to pay $5 or more a gallon... Then it's "drill baby drill." :innocent:

Pfft, every bit of that is fixable.

1. It can easily account for the speed of traffic on average and penalize those speeding through at absurd speeds. No one cars, now, if you do 5 over. But everyone gasps when there's no cop to catch the guy doing 15-30 over. And traffic will slow for poor conditions, where the speed limit may be (reasonably speaking) speeding if everyone is doing half that. You can still capture the guy doing that.
2. You can combine data points over time trivially. It's easy to get the plate in the scan and use multiple cameras to get a picture for how they were driving in general.
3. Obsessive speedometer checking will go away as soon as drivers realize they're not getting tickets for driving how they used to.


You could probably spot tailgating with cameras as well. There's a lot of traffic enforcement that's very automatable. A speed camera doesn't have to be a super simple radar gun that also takes pictures.

I don't doubt that it is all fixable. But if you go the way we've gone in the UK then every speed camera will be called a "safety" camera, all the while focussing purely on speed and not on the overall standard of driving.

Even if someone is doing 30 over, on an empty interstate who cares? 125 on an empty interstate in a decent car is probably safer than 25 past a primary school on a sunny Friday afternoon.

Traffic usually will slow for poor conditions but there's usually at least one bonehead who thinks that it's still safe to drive at 70 in torrential rain and heavy traffic that's doing 55. He's the one driving six inches off the back of the car and weaving through the traffic. In theory a camera can capture it but in practise it probably won't.

Then you've got the final flaw in law enforcement by camera. All it takes is for someone to take their license plates off or hide them, and the cameras are useless. When cameras do the job of traffic cops it's only a matter of time before the traffic cops aren't there any more. Just for good measure it also means if your car gets stolen you can look forward to endless fines coming through over the course of the next several days or weeks as the thief probably doesn't care about speed cameras.