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Comment by steve_gh | Hacker News Reader

...or you could drive sensibly within the speed limit.

Make the speed limit sensible, and I will.

I don't speed in Europe because 130 km/h is a perfectly fine limit; I've driven faster on uncontrolled Autobahn segments, but I'm not bothered when there is a limit. 65 mph on the NJ Turnpike (and only on the southern part) is not.

65mph is plenty fast. going beyond 70/75 is diminishing returns in the safety of other drivers, not to mention worse greenhouse emissions.

a crash at 80+ is so much worse than one at 65. and American highways are not the Autobahn. different design and engineering.

If anything, American highways are wider and straighter than the Autobahn.

But they are less well maintained and with fewer safety features, built to a lower cost per mile.

Being straighter is actually bad for safety (highway hypnosis).

You’ll find long stretches of interstates with no guard rails as well as state highways with direct intersections with rural roads.

The energy (damage) of a crash is proportional to the square of the speed. Therefore a crash at 80 units per hour has over 1 and a half times the amount of energy, and thus one and a half times the damage, as one at 65 units per hour.

That limit is completely reasonable on the NJ turnpike especially considering that the cultural norm is to go 5-10 mph over. American speed limits are determined with the expectation of drivers going over. In other countries the limit is more literal.

No cop is going to ticket you for going 70-75 on the turnpike.

In my town you don't get a ticket unless you are going 10mph over, and this is on surface streets. They might be stricter in the 20mph school zones though.

> No cop is going to ticket you for going 70-75 on the turnpike

Unless it's the end of the month and they have to meet quota and blah blah blah... Australia seems to get away with ruthlessly enforcing ridiculously low speed limits. The correct speed limit, by your own comment, seems to be 75 (120 km/h) at least.

Sometimes the speed limit is set to lower the accident rate on a particular piece of road. Like those 30 MPH curve warnings on a mountain road. Even in straight shots the amount of traffic could make 80 MPH significantly more dangerous than 70 MPH.

http://m8y.org/bloomcounty.jpg

Which one is it, driving sensibly or driving within the speed limit?

Yeah the internet it weird about speed limits for some reason meanwhile the moment you drive on real roads in the US you lean very quickly, even explicitly if you did in-cars in driver's ed, that the posted speed limit is the minimum.

In the places where it’s like that, enforcement is lax and you’ll never need a radar detector.

In the other places, it’s very simple to sit in the right lane and you won’t be going wildly slower than the rest of traffic. There are always trucks and governed vehicles on the road that are going the speed limit that you can swim through the stream with.

I used to be in the camp of defending the legality of radar detectors, and really I don’t think they need to be legal, but at the same time the only people buying them are dangerous assholes who treat public roads like their personal race track.

It takes at least one ticket to pay off the investment which means radar detector owners intend to be repeat offenders.

There are roads here that “feel” like a 35 or even 45mph road. The speed limit is 7. Yes, 7. It’s purely for local revenue.

Can of spray and a night off and they all become 70

There are back roads out there that drop 15 mph at the state line with no population around for miles. Detectors offer peace of mind for travel at a leisurely self-determined rate.

...on the long (9 miles to the next town), straight county road just by my house with a 50 mph speed limit that sees maybe 1 car per minute on average. There's a reason that the average speed there is 65mph+

What fun is that?

That being said, "speed culture" varies a lot from state to state. Where I live it's assumed and expected that you will speed, and in other areas you can get a ticket for going 1 over.

The legal and cultural ambiguity means that someone who is unsure of the real, enforced, culturally-accepted speed limit may want to use a radar detector.

Yup, in Idaho you’re pretty much expected to do +5. I swear they figure out the proper speed and subtract five from it. Going the speed limit will get you run over.

Then set the limits properly at the 85% mark. And ban speed limit fines from going into local coffers.

Dare I ask what the 85% mark is?

There was a rule at some point that the way to set a speed limit was to measure the speed of cars using that road, and set the limit so that 85% were under and 15% were over. I don't know how much this is actually used any more.

From a safety point of view the proper way to do it is to decide up front what speed limit you want on that road, and then design it so that drivers feel unsafe going over that speed. If you have to have a sign telling drivers to slow down, you designed the road wrong.

That's the basic standard for a traffic survey, which is sometimes required for enforcement. California has a speed trap law that prevents accepting radar evidence of vehicle speed unless the speed limit was set by a recent traffic survey, on a local road or school zone, or the limit is 65 for cars and 55 for trucks. Maybe some other exceptions.

I 100% agree on build the road to result in the behavior you want. Speed limit signs have some effect, but narrow lanes are much more effective.

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