Speed limits

[4x4ord]

The speed limit on the straight desolate paved road that goes past our place is 80 km/hr. The people who use the road drive whatever speed they please and for the most part it works fine ….. until you come across somebody driving 80 km per hour. The other day I was riding my bike through Banff national park and rode at the upper end of how fast traffic was moving …. about 130 km per hour. For the most part people drove 120 - 130 km/hr. Fortunately there wasn’t a sole driving the posted speed of 90 km/hr. How should we view speed limits? Is a speeding ticket simply a driving tax?

[Bumpyroad]

toedtoes wrote:

Bumpyroad wrote:

toedtoes wrote:

They changed the wording from "at least one car length per every 10mph" to "at least three seconds" because it is easier to figure out.

I don't think that going down the road counting one thousand one, one thousand two, etc. and restart when another car pulls in front of you is easier than to estimate a car length behind a vehicle. in any event, there will not be any precision into any method is used to determine distance.
bumpy

Many people have difficulty estimating distances. And what "is" a car length? Is it a vw bug or a pickup or a sedan or a station wagon? Counting to three seconds takes those arguments out of the equation.

is that count to three, or one onethousand, two two thousand, etc.? what cadence do you use? when that car length was used many years ago I would assume that it was for a standard sized vehicle so it would probably equate to 1.273 of today's vehicle length.
bumpy :S

[Cummins12V98]

The braking and handling of cars now compared to 1973 when I took my Drivers Ed simply do not compare. 2 seconds then makes 2 seconds now much safer.

Our teacher had us set in a chair in front of the class one at a time. He held a yardstick by the tips of his fingers with it dangling to the left of our right foot at one foot off the ground. He would let go and the challenge was to hit the stick before it hit the ground once he let it loose. No one could do this. He used this as an example of how long it takes to react.

Great teacher, when traveling at 70 on I-5 he always kept on us saying "keep it on the top side of 70". It was actually scary doing so in a 72 LTD boat of a car going thru the curves along Lake Samish.

[fj12ryder]

The 2 second rule is decent, but they say that stopping distance increases at about the square of speed. So if you're going twice as fast, the stopping distance is 4 times as long as it was at the slower speed. So you're probably right that the 2 second rule doesn't work as well at higher speeds.

[Thunderbolt]

MFL wrote:

Cummins12V98 wrote:
"but as you increase speed you also need more distance to give enough time to react"

My statement does exactly that! Faster you drive there will be more distance between you. Two seconds at 90 the distance between will be greater than at 55.

I stand by Mr Purvis' drivers ed recommendations many years later.

Exactly...I knew someone would question this, not thinking it through! I drove to drivers ed, but was not old enough to have a license yet. D's ed was fun, and I did learn from the experience.

Jerry

I have thought it through and regardless I stand by that 2 seconds will not be enough at greater speeds. Even though the distance will be greater I just don't see the increase being enough to compensate for the increased stopping distance it would take to react and actually stop if something happens in front of you. Most of the accidents as well as traffic jams I see on my 40 mile commute to work are from people following to close to the cars in front of them. I understand what you guys are talking about as I was taught the 2 second rule as well, but I just don't think it is enough at greater speeds. To each there own.

[4x4ord]

valhalla360 wrote:

toedtoes wrote:
You are making your own conclusion that hasn't been shown.

The data shows that you are more likely to Be IN A COLLISION if driving at the much slower speed. It does NOT show that the slow driving person is the CAUSE of the collision. Per the data from the NHTSA study, the CAUSE of that collision is most likely because the other driver was distracted, speeding, tailgating, not correctly judging the amount of space, overcorrecting, falling asleep, etc.

You are still focused on finding fault. I'm talking about eliminating accidents. I don't care about "fault" I want to eliminate crashes.

I want to enjoy driving and eliminating crashes is not that terribly important to me. Reducing speed limits for everyone because we know that some are texting while driving or for some other reason are incapable of driving 80 mph down a divided highway is frustrating. Occasionally we drive in a small city that has determined that some people are incapable of safely making left hand turns at uncontrolled intersections … they’ve got concrete curbs poured all over everywhere forcing traffic to make safe right hand turns…. I find driving to be getting more and more frustrating the safer it gets.

[toedtoes]

valhalla360 wrote:


Speed certainly isn't the only reason for crashes but it's been decades where it has been beaten into the American conscious that "speed kills", so not surprising, no one "claimed" is was low speed.

Increase space sounds good but in foggy conditions, if you slow down more than most, that means you have more interactions with cars passing you (or creating long lines of closely spaced cars behind you). It's not a simple problem for a human driver to solve but if you are doing 25mph in a 70mph zone because of visibility, you should be getting off the road entirely (short of an emergency). Adaptive speed control that can see thru fog and react more quickly is our best bet for solving low visibility issues.

Pile ups in foggy conditions are not because ONE person was driving 25. It is because too many people are driving 70 and driving too close to one another - all it takes is one vehicle to change lanes and a single car to hit their brakes and the chain reaction begins. None of those vehicles has enough space at the speeds they are driving to avoid hitting the car in front of them.

[toedtoes]

valhalla360 wrote:

toedtoes wrote:
You are making your own conclusion that hasn't been shown.

The data shows that you are more likely to Be IN A COLLISION if driving at the much slower speed. It does NOT show that the slow driving person is the CAUSE of the collision. Per the data from the NHTSA study, the CAUSE of that collision is most likely because the other driver was distracted, speeding, tailgating, not correctly judging the amount of space, overcorrecting, falling asleep, etc.

You are still focused on finding fault. I'm talking about eliminating accidents. I don't care about "fault" I want to eliminate crashes.

No, I am saying that the data does not suppoet your hypothesis that slow moving vehicles are the cause of collisions.

If you want to eliminate collisions then increase the distance between vehicles regardless of speed. As long as people feel the need to ride one another's bumpers, there will be collisions.

[toedtoes]

Bumpyroad wrote:

toedtoes wrote:

They changed the wording from "at least one car length per every 10mph" to "at least three seconds" because it is easier to figure out.

I don't think that going down the road counting one thousand one, one thousand two, etc. and restart when another car pulls in front of you is easier than to estimate a car length behind a vehicle. in any event, there will not be any precision into any method is used to determine distance.
bumpy

Many people have difficulty estimating distances. And what "is" a car length? Is it a vw bug or a pickup or a sedan or a station wagon? Counting to three seconds takes those arguments out of the equation.

[valhalla360]

JRscooby wrote:
This is 1 reason I always say the best vehicle for first car is a regular cab small pickup with 4 cyl, manual transmission. The low power reduces chance of showing off. Manual transmission mean pay more attention to driving. The frame IMHO is better when (not if) they wreck.
And most important; Think back, every time you got in trouble, or should of got in trouble, there was 3-4 friends in the car with you. The little cab reduces that chance.

My first car was exactly that. S-15 4cyl, stick with manual brakes, manual steering...I could light up the wheels in 3rd gear if I wanted to. I could also eat a burger with my left hand while driving with my right and regularly had 3 and sometimes 4 in the little regular cab...we won't talk about the 7-8 that occasionally rode in the truck bed.

Not that I disagree, it was a great option for a first vehicle and I wouldn't do some of that stuff now that I'm older...just funny that stupid kids will find a way to be stupid.

[valhalla360]

toedtoes wrote:

Again, the cause is tailgating. Had that person left more room between cars, there wouldn't have been a collision. People drive at different speeds - it's not for one person to "punish" others by tailgating them until they move out of the way. If traffic is so congested that you can not safely go around the slow driver, then you need to slow down accordingly. If traffic is such that you can safely go around the slow driver then you should do so. There is no legitimate reason for tailgating.

Keeping a safe distance from the car in front of you is Driving 101.

You are ignoring human nature. Not a good way to minimize crashes.

[valhalla360]

toedtoes wrote:
You are making your own conclusion that hasn't been shown.

The data shows that you are more likely to Be IN A COLLISION if driving at the much slower speed. It does NOT show that the slow driving person is the CAUSE of the collision. Per the data from the NHTSA study, the CAUSE of that collision is most likely because the other driver was distracted, speeding, tailgating, not correctly judging the amount of space, overcorrecting, falling asleep, etc.

You are still focused on finding fault. I'm talking about eliminating accidents. I don't care about "fault" I want to eliminate crashes.

[valhalla360]

toedtoes wrote:
Actually, this data was based on a project where the NHTSA went out to the accidents with the police and questioned the drivers at the scene and then compared those statements to the cars' data and the skidmarks, damage to the cars, etc.

As such, the report shows that no one stated "he was driving too slow" as the cause of the accident. Yet many many people stated they were distracted, speeding, tailgating, or had fallen asleep, etc. and that's why they hit the other car.

So your argument doesn't hold water.

In a 100 car pileup, it does not mean 99 people were going one faster speed and one was going much slower. That is your bias showing. All it means is that 99 people failed to not hit another car.

It could have been caused because there was a large piece of debris in the roadway and the first car swerved to avoid it thereby causing the cars around it to swerve and all the cars behind were following too close to stop in time.

It could be that one person was driving significantly faster than everyone else and didn't see the car ahead due to fog and hit it causing a chain reaction.

It could be that someone was trying to read a report on the way to work while driving and swerved to make their accident causing a chain reaction.

The idea that all (or even a significant number) of these pile ups were caused because one person chose to drive too slow is simply trying to justify speeding - and it doesn't work.

In reality, the best way to avoid a pile up is to increase the space between cars. If the car in front of you swerves, slows down, or farts, you should be far enough back to not have to slam on your brakes. And if you avoid hitting them and take a huge sigh of relief, you were still too close.

That's why the three second rules works - because the faster you are going the more room between you and the car in front of you. Because the higher speed requires a greater stopping distance. But most people maintain one car length or less between them and the car in front of them at any speed - because heaven forbid someone is allowed to move over in front of them. Heck, they might have to drop their speed from 70 to 67 for a minute in order to reestablish that space and that is unacceptable.

Speed certainly isn't the only reason for crashes but it's been decades where it has been beaten into the American conscious that "speed kills", so not surprising, no one "claimed" is was low speed.

Increase space sounds good but in foggy conditions, if you slow down more than most, that means you have more interactions with cars passing you (or creating long lines of closely spaced cars behind you). It's not a simple problem for a human driver to solve but if you are doing 25mph in a 70mph zone because of visibility, you should be getting off the road entirely (short of an emergency). Adaptive speed control that can see thru fog and react more quickly is our best bet for solving low visibility issues.

[Bumpyroad]

toedtoes wrote:

They changed the wording from "at least one car length per every 10mph" to "at least three seconds" because it is easier to figure out.

I don't think that going down the road counting one thousand one, one thousand two, etc. and restart when another car pulls in front of you is easier than to estimate a car length behind a vehicle. in any event, there will not be any precision into any method is used to determine distance.
bumpy

[noteven]

Driving trucks on 2 lane highways a lot teaches you to detect the "pre left turn pass" - the small vehicle has followed you for 30 miles just close enough the vehicles behind them cannot pass ... anyways they've been following, now they pass... spidy senses alert ... and yep, within a minute or two it's stand on the brakes and on with the left turn signal ...

[toedtoes]

JRscooby wrote:

I don't think that '1 car length per 10 mph' has been a recommendation for a long time. Mostly I have heard spacing given in seconds, not distance. And most do not mention that if you are following a car that can stop faster than you, you need to add time that you would be moving to the 2 seconds it takes you to react. In other words, a car 3 seconds behind a TT is likely not tailgating, but the TV pulling a TT 3 seconds behind the car probably is.

They changed the wording from "at least one car length per every 10mph" to "at least three seconds" because it is easier to figure out. There was always a question as to how long a car length is? And it's difficult for folks to determine that measurement while driving down the road. The actual distance recommendation is still the same - 3 seconds generally equates to one car length per each 10mph. But most people can do that simple measurement of counting to three while driving. It changed in the mid to late 80s.

Also, that is the mimimum recommendation. Nowadays, you'll hear " two seconds", but that was never the actual recommendation - that is a reduced distance to account for people in commuter vehicles who scream bloody murder if someone dares to merge into their lane during their commute home. It is better than no space, but closes up the open space in front of them so they are more likely to maintain it. It is used as a "bargaining chip" - "you should stay at least three seconds behind", "but all those other drivers will cut in front of me and I will never get home", "OK, then do two seconds. It's enough to give you time to react, but won't leave that huge empty space in front of you". And yes, I heard that conversation every time I took our required defensive driver course for work for the past 30 years.

In reality, you want to stay at least three seconds behind the car in front of you. Other factors should increase that distance - weather, your vehicle's capabilities, road conditions, any impairment to your response speeds, etc.