What speed would you drive? Would you take close corners at 120km/h? People (on average) drive at the speed their actually very well tuned survival instinct tells them to.
I disagree that the average driver has well-tuned instincts. Accidents are rare enough events that you can drive poorly for a long time and still not end up in a seriously bad situation, especially in areas where inclement conditions are also rare.
The first time you lose control of your car might be in icy conditions, and might be not just losing control, but spinning out of control in traffic. The line between in control and not in control can be very thin, and so hard to know how close you are to it.
I mean self-preservation instincts, not driving instincts. I agree totally with the later!
By self-preservations instincts what I mean is that most people will try to be as safe as possible on the road, meaning drive slower on low-visibility situations, when there are many pedestrians around, etc. You cannot account on unforeseen circumstances or lack of knowledge, but otherwise people will try very hard not to get into harm's way.
Without a speed limit, I'd take i-70 from KC to STL at about (160~mph) 250km/h for 95% of it. I'd make day trips just to get white castle at white knuckle speeds.
I-70 is a mostly straight highway with a divider, it'd be pretty safe as long as it's not crowded. Autobahn speed limits are certainly doable in many of America's highways.
I don’t think that’s true at all (though I only have my own experience to go off of). I tend to use the speed limit as a point of reference, and then drive a little above it. Prior experience has told me that going the speed limit plus some percentage ‘feels’ safe. If there were no speed limit I’d actually have to pay more attention to the road and surrounding environment to determine what a safe speed is. Right now most people’s ‘survival instinct’ is basically speed limit + some delta in clear conditions. That delta may change from driver to driver, but in general everyone drives within 10-20% of the speed limit.
As a fun thought experiment, imagine what would happen if your residential speed limit were raised from 25mph to 70mph. People may not hit the 70mph limit, but I can almost guarantee that the average speed would increase significantly, perhaps even dangerously in some cases. I don’t have much faith in people’s ability to judge space and speed accurately, particularly when they aren’t used to doing so. And this includes myself.
Ah but that is a whole different issue, the problem is that for the last few decades residential areas have been designed more and more like high-speed areas, and that had a larger impact on driver speed than the actual posted sign. I cannot seem to find the original articles but here are a couple of related ones:
This is well-studied. It turns out that the 85th percentile speed (the speed where 85% of drivers are below that speed, 15% above) is nearly insensitive to speed limit. Road design is the biggest single determinant of travel speed. http://www.lsp.org/pdf/troopc85thSpeed.pdf
> Won’t raising the speed limit cause people to
drive faster and cause more crashes?
> The Federal Highway Administration studied nearly 200
roads in 22 states where speed limits were raised, lowered
or left unchanged. Prior to the speed limit change, 55
percent of drivers exceeded the posted speed limits. After
speed limits were raised or lowered as much as 20 mph,
there was a slight change in speed, but generally less than 1
mph. There were no significant changes in crashes,
although crashes tended to decrease where speed limits
were increased to realistic levels. Also, there was little
effect on speeds or crashes on intersecting or nearby
roadways.
This is for federal highways, traffic in a city should not go faster than 25mph in most shared spaces. Motorways is a different subject, but there should only be overpasses or resegined roads and traffic lights for such places.
I would like the speed limit on my interstates and highways to go up to 70(they're all straight. 55 is just the only speed limit around here). Driving at 65-70 feels safe in normal conditions. Driving above 70 feels a bit too fast.
Speed limits should be more variable depending upon car size and braking power though. I hate having to fear that I might be pulled over for going a bit above the speed limit when there are so many more threats than just speed. I don't believe speed limits should be anything more than a suggestion with dangerous driving being the focus.
I find this is extremely dependent on car. I've had cars that felt like you were about to die at 55 mph, and I've had cars that you couldn't tell you were going fast until you were really moving. For laughs, as my wife and I were driving home one afternoon earlier this year on a completely empty stretch of I-5 south of Portland, I casually accelerated up to about 110 and left it there for maybe a minute, then eased back down to normal speed as we came up into traffic. She never even looked up, didn't notice. But then again, we were in my brand new Camaro SS and I'm not positive it even got over 2000 RPM for that exercise, so I guess that's not a surprise.
So I guess I'm saying I agree. Speed limits are pretty arbitrary, there are a lot of things drivers do every day that are far more dangerous than merely speeding. Closure rate, unsafe passes, tailgating, cutting people off, etc.
/don't get me started about how people drive around you if you're towing a travel trailer, what the heck is it with people?
On most roads around where I live, if you are driving exactly the speed limit, you are a slow moving obstacle that is probably more of a danger due to the extreme speed differential with the other drivers who are 10-20 MPH over the limit. I’d hope self driving cars were programmed to deal safely within the bounds of reality. If there is nobody else on the road, sure drive the speed limit. If cars are whizzing past you on all sides you’re a hazard even if you’re obeying the law.
Depends on the conditions. With moderate temperature and dry conditions every single corner on a highway can be taken at 120km/h on any modern car, the overwhelming majority of them can be taken far in excess of 200km/h depending on the car's characteristics.
Then again under bad conditions on a 90km/h roads my survival instinct like you mentioned hasn't allowed me to go past 20-30km/h sometimes.
Prevailing traffic plus 10-15 mph. Or 135-ish with good conditions and no other cars. My days of real speed runs are behind me, and 135 is fast enough to keep things interesting and make good time without getting too crazy.
I would say they should be able to drive up to 15% higher than the speed limit at their discretion. So in a 35 zone they could go up to 40. But that's not a question for me to answer.I just know that the answer isn't that they follow the letter of the law all the time.
