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>Set extremely low speeds that don't make sense on highways. Allow most people to go 10-15 above. I doubt people really speed because the limits have been set

>Set extremely low speeds that don't make sense on highways. Allow most people to go 10-15 above. I doubt people really speed because the limits have been set too low and the people know better what is an ideal speed limit. I think people_think_ they know better what the speed limit is, and/or reason "well if 60mph is okay, 75 mph can't be that bad, I'm barely speeding and I'm in a rush". At least, that's the attitude I've seen with people who regularly speed. If you were to raise the speed limit to 75mph, people would just use the same logic to drive 90mph instead.

scarface74 8y ago
http://www.sehinc.com/news/truth-about-speed-limits-explained-engineer http://www.sehinc.com/news/truth-about-speed-limits-explaine... There is no guarantee that a speed limit will have any effect on driving behaviors. The fact is, when driving, most motorists choose a speed in which they personally feel both comfortable and safe.
- Joeri 8y ago
  https://en.m.wikipedia.org/wiki/Autobahn#Travel_speeds https://en.m.wikipedia.org/wiki/Autobahn#Travel_speeds on a free-flowing section in 1992, the recorded average speed was 132 km/h (82 mph) with 51% of drivers exceeding the recommended speed. The autobahn has a long history proving that people feel comfortable and safe at excessive velocities.
  - scarface74 8y ago
    The autobahn is different. The people who drive on the autobahn self select because they want to drive fast and they have a disproportionate number of cars that can handle the speed. I doubt I would have been driving my first car - a Mercury Tracer - on the autobahn. But 80 miles per hour is not an abnormal speed on the highway. The posted speed limit is so rarely enforced, that it still isn’t a deterrent. For instance, the speed limit on GA 400 is 70. But you’d better be in the slow lane if you only go 70mph. https://www.11alive.com/article/news/local/commuters-respond-to-sheriffs-hilarious-and-true-ga-400-speeding-post/85-540154004 https://www.11alive.com/article/news/local/commuters-respond...
    - philwelch 8y ago
      I'm not sure I understand this point. The autobahn is just the German highway system. Do Germans who don't want to drive fast and don't own fast cars all emigrate to Denmark or something?
      - NegativeLatency 8y ago
        When most Americans talk abou the autobahn like this they actually mean the sections without speed restrictions
        rconti 8y ago
        So do Germans who want to get from one city to another exit the Autobahn and drive on surface streets to avoid the de-restricted sections? Of course not.
        gehwartzen 8y ago
        They just get into the correct lane.
      - scarface74 8y ago
        I thought it was understood in context and because Americans usually refer to "the Autobahn" as the parts without speed limits.
        rconti 8y ago
        The criticism of your comment stands, regardless of whether you're talking about a section that is restricted vs derestricted. Do people driving on derestricted sections self-select and have cars better able to handle the speeds? Does anyone in Germany only drive on restricted sections? You comment as if the derestricted sections are just some racetrack in the middle of nowhere for which people self-select. No, they're just roads going from one place to another, like any other road. And Germany doesn't kick out citizens who don't want to drive fast, or offer easy citizenship for those who do.
  - sDlEzAtyoNAz 8y ago
    Are you suggesting those "excessive" velocities are not actually safe?
    - Joeri 8y ago
      If you look at the stopping distances at 80+ mph I don't see how you can argue those speeds are safe.
      - sDlEzAtyoNAz 8y ago
        If you look at the low level of fatalities on the autobahn, I don't see how you can argue those speeds are unsafe.
        jschwartzi 8y ago
        It's a lot harder to get a license in Germany than in the US, and there's more of an expectation that you keep your vehicle in good repair. I could argue that the speed limit on the Autobahn is a result of selecting for more conscientious and capable drivers rather than proof that higher speeds are safe in general.
        sDlEzAtyoNAz 8y ago
        I'm not sure what it would mean for a speed to be "safe in general". What is the general case? Whether a particular speed is safe or not is situation dependent, and the situation absolutely includes the quality of the drivers and vehicles involved.
        jschwartzi 8y ago
        Which is essentially what I'm saying, that higher speeds on the Autobahn may be safe because the drivers are better and the cars are in better condition, but that that wouldn't work here in the US because our drivers aren't as competent and their cars are more likely to fail at Autobahn speeds.
  - tomsmeding 8y ago
    Here in the Netherlands, and I think also in other places in Europe, 130 km/h is the normal highway speed limit, though in places it's at 120 or 100 instead. This was raised from some time ago, when the normal maximum was 120 instead of 130. So it seems that 130 km/h (81 mph) is not all that excessive.
  - deleted 8y ago
    [deleted]
  - thescriptkiddie 8y ago
    The recommended speed on the Autobahn is 130 km/h, but in the unrestricted sections you can technically drive as fast as you want, conditions permitting. The fact that the average speed in an unrestricted section with light traffic was only 132 km/h suggests that the vast majority of drivers don't actually want to drive much faster than that.
quasse 8y ago
> If you were to raise the speed limit to 75mph, people would just use the same logic to drive 90mph instead. Luckily there are plenty of places that have done just that that we can learn from. WI just raised a lot of its highway speed limits to 70mph for example. Anecdotally, people used to drive in the 75mph range before the speed limit was raised and would deal with the occasional ticket for 10 over. In the general case, the average highway speed seems to have stayed at 75mph after the change. I've noticed something similar in South Dakota where the speed limit is 80. I rarely saw someone go more than 5 over, and would frequently encounter people driving at 75mph.
- zip1234 8y ago
  Also in Michigan, they just raised the speed limit on some Michigan expressways to 75 from 70 because they found that was the speed most people went.
chrischen 8y ago
Perhaps for places with realistic speed limits, but there are places with unrealistic limits: http://articles.chicagotribune.com/2013-12-17/opinion/ct-enforce-speed-limits-edit-1217-jm-20131217_1_speed-limit-70-mph-state-troopers http://articles.chicagotribune.com/2013-12-17/opinion/ct-enf...
- dionian 8y ago
  Still true to this day - I've been pulled over for speeding just over 80, and the State Police knocked my recorded speed down to just below 80 so I wouldn't get a very serious "aggravated" speeding ticket (something like 15mph over limit)
cortesoft 8y ago
I think you have a fundamental misunderstanding about how people drive. People don't look at a speed limit and then drive 15 over; they drive the speed they feel comfortable with, regardless of the speed limit. Studies have shown this: Q. Wouldn’t everyone drive faster if the speed limit was raised? A. No, the majority of drivers will not go faster than what they feel is comfortable and safe regardless of the speed limit. For example, an 18-month study following an increase in the speed limit along the New York Thruway from 55 to 65 mph, determined that the average speed of traffic, 68 mph, remained the same. Even a national study conducted by Federal Highway Administration also concluded that raising or lowering the speed limit had practically no effect on actual travel speeds https://www.motorists.org/wp-content/uploads/2015/05/speed-limit-fact-sheet.pdf https://www.motorists.org/wp-content/uploads/2015/05/speed-l...
- dyarosla 8y ago
  I don’t think dismissing the parent comment based on a study is fair. Anecdotally, I drive the way the parent describes, and several comments also corroborate with that. Likely that a non negligible portion of the population drive this way.
  - mikestew 8y ago
    I don’t think dismissing the parent comment based on a study is fair. Well, there's a surprising turn of events on HN: an appeal to discard the findings of a study in favor of one poster's suppositions, and another's anecdata. :-)
    - dyarosla 8y ago
      The irony is def not lost on me ;)
  - cortesoft 8y ago
    If you look at the studies, they actually show this. There is a small percentage of drivers (something like 5-15%) that always try to drive at the speed limit, even if that is lower than the speed they would naturally drive at. This is one of the reasons experts argue that you NEED to set the speed limit at the natural speed people will drive at; otherwise, you will have a big speed difference between the majority who drive at the comfortable, faster, speed, and the 15% who are driving slower at the speed limit. You want the two groups to drive at the same speed.
jchw 8y ago
Generally in my experience people drive around 70-75 mph regardless of the speed limit. At 50mph some people may lean lower, but it's generally usual to see people on 75mph highways going 75mph. There were some in Michigan.
packet_nerd 8y ago
Just my observation, in my state the highway speed limit is 80 and people drive at right around 80, and drop down to 75 at night. Then, on a Texas road where it was 85, I was surprised to see most people still going about 80. And in a neighboring state where the speed limit is 70 for similar roads, people still drive right around 80. And once I drove through Chicago at night through a stretch where the speed limit was 45, and people were still going 75 - 80... not sure what the deal with 80 is, but it seems to be the sweet spot a lot of the time.
- zzzeek 8y ago
  it's the cars. the relative motion that is transferred into the cab, the handling, etc. back in the 70s/80s when folks drove huge metal deathtraps with barely any seatbelt that nobody wore anyway, on top of a giant floating weight distribution that would easily spin out, 80mph was an insanely high speed.
zzzeek 8y ago
I live in a state that has 55 mph limit, and I've spent lots of time in states that have a 70mph limit. everyone drives the same speed regardless, around 75-80 on a straight and wide highway in the left lane, around 65 in the right lane. the sign means nothing.
AcerbicZero 8y ago
Surprisingly enough, that tends to not be the case - http://www.sehinc.com/news/truth-about-speed-limits-explained-engineer http://www.sehinc.com/news/truth-about-speed-limits-explaine... My personal anecdotal evidence on this, having recently driven cross country on I-80 (mostly 80MPH speed limits) and through Montana on I-90 (Again, mostly 80 MPH) shows that people drive at a speed that is safe for them. My car, and those that also seemed to drive a few MPH over the limit were all newer, highly capable vehicles, and the largest added risk was the chance of running into excessively slow moving traffic. When the visibility dropped, I slowed down, and when the visibility was clear, there was no additional risk in pushing it up a few MPH.
imgabe 8y ago
> If you were to raise the speed limit to 75mph, people would just use the same logic to drive 90mph instead. I've driven in parts of the country where the speed limit is 75 or even 80 and that wasn't my experience. There were not a lot of people blowing past me doing 95.
- zrobotics 8y ago
  Drive on I25 north of Cheyenne WY on a Sunday, and I guarantee ~50% of out of state cars are going that speed.
mikestew 8y ago
If you were to raise the speed limit to 75mph, people would just use the same logic to drive 90mph instead. This is easily tested in the western U. S., where there exist states with speed limits of 75mph or higher. There's a point at which I quit getting passed, and start being the one doing most of the passing. That point is just a bit north of 80mph. Anecdotally, same point it was when speed limits were lower. IOW, when I'd ride the interstates of AZ or WY twenty years ago, my ratio of passed/passing at 90mph was about the same as it is now. But surely someone has done an actual study on this.
volkk 8y ago
Anecdotally speaking, I've driven a lot and 75-80 is ideal speed for me. When I drove in texas where in certain areas, the speed limit is 80-85, I still drove around 80. Once you hit 85/90, a car just becomes too shaky/unstable feeling.
- 2trill2spill 8y ago
  > Once you hit 85/90, a car just becomes too shaky/unstable feeling. Not my car, I often look down and see that I'm going 90 when it feels like I'm going 70.
- grkvlt 8y ago
  I think Ferrari, Porsche, et al would beg to differ. Most high end Mercedes, Audi or BMW cars are limited to 155 mph but you'd be hard pressed to tell the difference in ride quality between the top 50 mph of the range and the bottom 50. If your car gets shaky and unstable when you hit 90 mph then I'm sorry but you just don't have a very good vehicle.
  - volkk 8y ago
    you can't assume that most of the general population has these cars, though. a 2013 camry going 90 MPH is not something i want to be in, nor do i trust anyone going that fast to be in control of their vehicle and making high speed decisions
    - dingaling 8y ago
      I've been up to 130mph as a passenger in mid-2000s Kia Magentis saloon ( Camry-sized sedan ) on a track and it was rock-solid. Car chassis are very performant nowadays.
  - Aramgutang 8y ago
    The car is not all that's at play here. Road surface quality is a huge factor. I've pushed a rental Merc past 180 km/h (110 mph) on a reasonably well-paved outback road, and it was downright unpleasant to drive at that speed from the vibration. On a smoother highway I would guess it'd still become unpleasant past 200 km/h (125 mph). Personally, I also found driving at those speeds too mentally taxing. The lack of time to react, the lack of maneuverability, and the huge braking distance were just too stressful. You couldn't let your thoughts, let alone your eyes, off the road for even a second. On that particular trip, I had driven for 18 hours (excluding short breaks and a 3-hour nap), most of it at ~100 km/h. If I had the option of driving 180 km/h the whole time and save 8 hours, I would not take it. That said, if there were no speed limits, I'd probably drive 130-150 km/h (80-95 mph), depending on the road, which isn't far from what volkk said.
gwbas1c 8y ago
It's regional. I've seen an interview on MA TV with a State Trooper where the cop basically said that 5-10 over was totally OK on a newly-opened freeway. Then again, MA speed limits tend to be lower than surrounding states.
closeparen 8y ago
Many speed limits were set at a particular percentile of observed speeds early in the road’s life, then lowered in the 1970s to conserve fuel. Safety-oriented calibration is less common than you’d think. Drivers mostly go the speed they are comfortable with, which is a function of the roadway’s design and conditions. Traffic engineers are learning that you can’t just slap a 30mph limit sign on something that feels like an interstate highway, but must instead use the road’s physical characteristics to slow drivers down.
rconti 8y ago
That's not what the evidence shows. Also, it goes against traffic design principles, even in the US. (see: 85th percentile)

scarface74 8y ago

http://www.sehinc.com/news/truth-about-speed-limits-explained-engineer http://www.sehinc.com/news/truth-about-speed-limits-explaine... There is no guarantee that a speed limit will have any effect on driving behaviors. The fact is, when driving, most motorists choose a speed in which they personally feel both comfortable and safe.

Joeri 8y ago
https://en.m.wikipedia.org/wiki/Autobahn#Travel_speeds https://en.m.wikipedia.org/wiki/Autobahn#Travel_speeds on a free-flowing section in 1992, the recorded average speed was 132 km/h (82 mph) with 51% of drivers exceeding the recommended speed. The autobahn has a long history proving that people feel comfortable and safe at excessive velocities.
- scarface74 8y ago
  The autobahn is different. The people who drive on the autobahn self select because they want to drive fast and they have a disproportionate number of cars that can handle the speed. I doubt I would have been driving my first car - a Mercury Tracer - on the autobahn. But 80 miles per hour is not an abnormal speed on the highway. The posted speed limit is so rarely enforced, that it still isn’t a deterrent. For instance, the speed limit on GA 400 is 70. But you’d better be in the slow lane if you only go 70mph. https://www.11alive.com/article/news/local/commuters-respond-to-sheriffs-hilarious-and-true-ga-400-speeding-post/85-540154004 https://www.11alive.com/article/news/local/commuters-respond...
  - philwelch 8y ago
    I'm not sure I understand this point. The autobahn is just the German highway system. Do Germans who don't want to drive fast and don't own fast cars all emigrate to Denmark or something?
    - NegativeLatency 8y ago
      When most Americans talk abou the autobahn like this they actually mean the sections without speed restrictions
      - rconti 8y ago
        So do Germans who want to get from one city to another exit the Autobahn and drive on surface streets to avoid the de-restricted sections? Of course not.
        gehwartzen 8y ago
        They just get into the correct lane.
    - scarface74 8y ago
      I thought it was understood in context and because Americans usually refer to "the Autobahn" as the parts without speed limits.
      - rconti 8y ago
        The criticism of your comment stands, regardless of whether you're talking about a section that is restricted vs derestricted. Do people driving on derestricted sections self-select and have cars better able to handle the speeds? Does anyone in Germany only drive on restricted sections? You comment as if the derestricted sections are just some racetrack in the middle of nowhere for which people self-select. No, they're just roads going from one place to another, like any other road. And Germany doesn't kick out citizens who don't want to drive fast, or offer easy citizenship for those who do.
- sDlEzAtyoNAz 8y ago
  Are you suggesting those "excessive" velocities are not actually safe?
  - Joeri 8y ago
    If you look at the stopping distances at 80+ mph I don't see how you can argue those speeds are safe.
    - sDlEzAtyoNAz 8y ago
      If you look at the low level of fatalities on the autobahn, I don't see how you can argue those speeds are unsafe.
      - jschwartzi 8y ago
        It's a lot harder to get a license in Germany than in the US, and there's more of an expectation that you keep your vehicle in good repair. I could argue that the speed limit on the Autobahn is a result of selecting for more conscientious and capable drivers rather than proof that higher speeds are safe in general.
        sDlEzAtyoNAz 8y ago
        I'm not sure what it would mean for a speed to be "safe in general". What is the general case? Whether a particular speed is safe or not is situation dependent, and the situation absolutely includes the quality of the drivers and vehicles involved.
        jschwartzi 8y ago
        Which is essentially what I'm saying, that higher speeds on the Autobahn may be safe because the drivers are better and the cars are in better condition, but that that wouldn't work here in the US because our drivers aren't as competent and their cars are more likely to fail at Autobahn speeds.
- tomsmeding 8y ago
  Here in the Netherlands, and I think also in other places in Europe, 130 km/h is the normal highway speed limit, though in places it's at 120 or 100 instead. This was raised from some time ago, when the normal maximum was 120 instead of 130. So it seems that 130 km/h (81 mph) is not all that excessive.
- deleted 8y ago
  [deleted]
- thescriptkiddie 8y ago
  The recommended speed on the Autobahn is 130 km/h, but in the unrestricted sections you can technically drive as fast as you want, conditions permitting. The fact that the average speed in an unrestricted section with light traffic was only 132 km/h suggests that the vast majority of drivers don't actually want to drive much faster than that.

quasse 8y ago

> If you were to raise the speed limit to 75mph, people would just use the same logic to drive 90mph instead. Luckily there are plenty of places that have done just that that we can learn from. WI just raised a lot of its highway speed limits to 70mph for example. Anecdotally, people used to drive in the 75mph range before the speed limit was raised and would deal with the occasional ticket for 10 over. In the general case, the average highway speed seems to have stayed at 75mph after the change. I've noticed something similar in South Dakota where the speed limit is 80. I rarely saw someone go more than 5 over, and would frequently encounter people driving at 75mph.

zip1234 8y ago
Also in Michigan, they just raised the speed limit on some Michigan expressways to 75 from 70 because they found that was the speed most people went.

chrischen 8y ago

Perhaps for places with realistic speed limits, but there are places with unrealistic limits: http://articles.chicagotribune.com/2013-12-17/opinion/ct-enforce-speed-limits-edit-1217-jm-20131217_1_speed-limit-70-mph-state-troopers http://articles.chicagotribune.com/2013-12-17/opinion/ct-enf...

dionian 8y ago
Still true to this day - I've been pulled over for speeding just over 80, and the State Police knocked my recorded speed down to just below 80 so I wouldn't get a very serious "aggravated" speeding ticket (something like 15mph over limit)

cortesoft 8y ago

I think you have a fundamental misunderstanding about how people drive. People don't look at a speed limit and then drive 15 over; they drive the speed they feel comfortable with, regardless of the speed limit. Studies have shown this: Q. Wouldn’t everyone drive faster if the speed limit was raised? A. No, the majority of drivers will not go faster than what they feel is comfortable and safe regardless of the speed limit. For example, an 18-month study following an increase in the speed limit along the New York Thruway from 55 to 65 mph, determined that the average speed of traffic, 68 mph, remained the same. Even a national study conducted by Federal Highway Administration also concluded that raising or lowering the speed limit had practically no effect on actual travel speeds https://www.motorists.org/wp-content/uploads/2015/05/speed-limit-fact-sheet.pdf https://www.motorists.org/wp-content/uploads/2015/05/speed-l...

dyarosla 8y ago
I don’t think dismissing the parent comment based on a study is fair. Anecdotally, I drive the way the parent describes, and several comments also corroborate with that. Likely that a non negligible portion of the population drive this way.
- mikestew 8y ago
  I don’t think dismissing the parent comment based on a study is fair. Well, there's a surprising turn of events on HN: an appeal to discard the findings of a study in favor of one poster's suppositions, and another's anecdata. :-)
  - dyarosla 8y ago
    The irony is def not lost on me ;)
- cortesoft 8y ago
  If you look at the studies, they actually show this. There is a small percentage of drivers (something like 5-15%) that always try to drive at the speed limit, even if that is lower than the speed they would naturally drive at. This is one of the reasons experts argue that you NEED to set the speed limit at the natural speed people will drive at; otherwise, you will have a big speed difference between the majority who drive at the comfortable, faster, speed, and the 15% who are driving slower at the speed limit. You want the two groups to drive at the same speed.

jchw 8y ago

Generally in my experience people drive around 70-75 mph regardless of the speed limit. At 50mph some people may lean lower, but it's generally usual to see people on 75mph highways going 75mph. There were some in Michigan.

packet_nerd 8y ago

Just my observation, in my state the highway speed limit is 80 and people drive at right around 80, and drop down to 75 at night. Then, on a Texas road where it was 85, I was surprised to see most people still going about 80. And in a neighboring state where the speed limit is 70 for similar roads, people still drive right around 80. And once I drove through Chicago at night through a stretch where the speed limit was 45, and people were still going 75 - 80... not sure what the deal with 80 is, but it seems to be the sweet spot a lot of the time.

zzzeek 8y ago
it's the cars. the relative motion that is transferred into the cab, the handling, etc. back in the 70s/80s when folks drove huge metal deathtraps with barely any seatbelt that nobody wore anyway, on top of a giant floating weight distribution that would easily spin out, 80mph was an insanely high speed.

zzzeek 8y ago

I live in a state that has 55 mph limit, and I've spent lots of time in states that have a 70mph limit. everyone drives the same speed regardless, around 75-80 on a straight and wide highway in the left lane, around 65 in the right lane. the sign means nothing.

AcerbicZero 8y ago

Surprisingly enough, that tends to not be the case - http://www.sehinc.com/news/truth-about-speed-limits-explained-engineer http://www.sehinc.com/news/truth-about-speed-limits-explaine... My personal anecdotal evidence on this, having recently driven cross country on I-80 (mostly 80MPH speed limits) and through Montana on I-90 (Again, mostly 80 MPH) shows that people drive at a speed that is safe for them. My car, and those that also seemed to drive a few MPH over the limit were all newer, highly capable vehicles, and the largest added risk was the chance of running into excessively slow moving traffic. When the visibility dropped, I slowed down, and when the visibility was clear, there was no additional risk in pushing it up a few MPH.

imgabe 8y ago

> If you were to raise the speed limit to 75mph, people would just use the same logic to drive 90mph instead. I've driven in parts of the country where the speed limit is 75 or even 80 and that wasn't my experience. There were not a lot of people blowing past me doing 95.

zrobotics 8y ago
Drive on I25 north of Cheyenne WY on a Sunday, and I guarantee ~50% of out of state cars are going that speed.

mikestew 8y ago

If you were to raise the speed limit to 75mph, people would just use the same logic to drive 90mph instead. This is easily tested in the western U. S., where there exist states with speed limits of 75mph or higher. There's a point at which I quit getting passed, and start being the one doing most of the passing. That point is just a bit north of 80mph. Anecdotally, same point it was when speed limits were lower. IOW, when I'd ride the interstates of AZ or WY twenty years ago, my ratio of passed/passing at 90mph was about the same as it is now. But surely someone has done an actual study on this.

volkk 8y ago

Anecdotally speaking, I've driven a lot and 75-80 is ideal speed for me. When I drove in texas where in certain areas, the speed limit is 80-85, I still drove around 80. Once you hit 85/90, a car just becomes too shaky/unstable feeling.

2trill2spill 8y ago
> Once you hit 85/90, a car just becomes too shaky/unstable feeling. Not my car, I often look down and see that I'm going 90 when it feels like I'm going 70.
grkvlt 8y ago
I think Ferrari, Porsche, et al would beg to differ. Most high end Mercedes, Audi or BMW cars are limited to 155 mph but you'd be hard pressed to tell the difference in ride quality between the top 50 mph of the range and the bottom 50. If your car gets shaky and unstable when you hit 90 mph then I'm sorry but you just don't have a very good vehicle.
- volkk 8y ago
  you can't assume that most of the general population has these cars, though. a 2013 camry going 90 MPH is not something i want to be in, nor do i trust anyone going that fast to be in control of their vehicle and making high speed decisions
  - dingaling 8y ago
    I've been up to 130mph as a passenger in mid-2000s Kia Magentis saloon ( Camry-sized sedan ) on a track and it was rock-solid. Car chassis are very performant nowadays.
- Aramgutang 8y ago
  The car is not all that's at play here. Road surface quality is a huge factor. I've pushed a rental Merc past 180 km/h (110 mph) on a reasonably well-paved outback road, and it was downright unpleasant to drive at that speed from the vibration. On a smoother highway I would guess it'd still become unpleasant past 200 km/h (125 mph). Personally, I also found driving at those speeds too mentally taxing. The lack of time to react, the lack of maneuverability, and the huge braking distance were just too stressful. You couldn't let your thoughts, let alone your eyes, off the road for even a second. On that particular trip, I had driven for 18 hours (excluding short breaks and a 3-hour nap), most of it at ~100 km/h. If I had the option of driving 180 km/h the whole time and save 8 hours, I would not take it. That said, if there were no speed limits, I'd probably drive 130-150 km/h (80-95 mph), depending on the road, which isn't far from what volkk said.

gwbas1c 8y ago

It's regional. I've seen an interview on MA TV with a State Trooper where the cop basically said that 5-10 over was totally OK on a newly-opened freeway. Then again, MA speed limits tend to be lower than surrounding states.

closeparen 8y ago

Many speed limits were set at a particular percentile of observed speeds early in the road’s life, then lowered in the 1970s to conserve fuel. Safety-oriented calibration is less common than you’d think. Drivers mostly go the speed they are comfortable with, which is a function of the roadway’s design and conditions. Traffic engineers are learning that you can’t just slap a 30mph limit sign on something that feels like an interstate highway, but must instead use the road’s physical characteristics to slow drivers down.

rconti 8y ago

That's not what the evidence shows. Also, it goes against traffic design principles, even in the US. (see: 85th percentile)