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Confusion over what is a "safe following distance" has QUT [(Queensland University of Technology)] road safety researchers calling for a standardised definition to prevent tailgating.
- Tailgating conclusively linked to rear-end crashes
- Most drivers leave less than a 2 second gap between them and the vehicle in front
- Rear-enders account for one in five Queensland crashes
Dr Sebastien Demmel, from QUT's Centre for Accident Research & Road Safety -- Queensland (CARRS-Q), said the results of the study which found 50 per cent of drivers tailgate, was being presented at the 2017 Australasian Road Safety Conference in Perth today.
"This study, for the first time conclusively linked tailgating with rear-end crashes, but we also identified confusion among drivers over what is deemed to be a safe following distance," he said.
"Despite drivers perceiving they are following at a safe distance, our on-road data showed that in reality most don't leave the recommended two to three second gap," he said.
"At some locations 55 per cent of drivers were found to leave less than a two second gap between them and the vehicle in front, and 44 per cent less than a one second [gap]."
A safe following distance is 5 feet. While looking at a smartphone.
(Score: 2) by LoRdTAW on Thursday October 12 2017, @10:28PM (16 children)
The problem is the slow moron in the passing/hammer lane is obeying the speed limit and well within their right to do so. Patience is the problem.
(Score: 0) by Anonymous Coward on Thursday October 12 2017, @10:33PM (6 children)
I might be going 65, but I really want to go 90. I just can't afford to be dealing with cops. Ditch the damn speed limit, and I won't feel a need to cause such problems.
No, I do not wish to go 55 in the other lane, with frequent slowdowns to 45 when merging.
(Score: 3, Interesting) by Arik on Thursday October 12 2017, @10:43PM (1 child)
I sympathize. Fortunately the main place I might want to go 90 did actually get raised to 80, and as long as you're >=10 below it's generally too petty for them to bother hitting the lights. I'm really ok with that, it's close enough. But somehow it's still a problem once you figure in all the other drivers. A bunch hold 65-70 the whole way, they usually stay in the right lane but when mister 69mph is in front of me passing mr 65mph... grrr. And then there's still the occasional guy that zooms up on my tail out of nowhere doing ~100 and trying to pass on the right where it isn't safe. Still, I do think increasing the speed limit has probably reduced the accidents. May have increased the average severity though. I'll see if I can find the numbers.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by frojack on Friday October 13 2017, @08:12AM
Probably because those numbers don't exist. I've looked. You can find lots of claims, but those are usually speculative (and politically motivated) and aren't comparing the same traffic mix on the same roads.
Mostly what you find is that the improvement in automobiles reduces accidents and highway deaths to such a great degree that an increase of speed limits from 75 to 80 has zero measurable effect.
Try that 80mph in a 50-60's era car and you would see a lot more accidents, and a lot more deadly ones. Those cars were hanging on for dear life at 80. Modern cars drive at 80 like your doing 45.
No, you are mistaken. I've always had this sig.
(Score: 2) by bob_super on Thursday October 12 2017, @11:02PM (3 children)
STAY IN THE RIGHTMOST LANE UNLESS YOU'RE PASSING SOMEONE! CHANGING LANES AS NEEDED IS NOT A DISEASE, IT'S THE RULE!
This reminder of the law provided to you by the billions of hours and dollars wasted in traffic jams caused by improper lane usage. TMYK.
(Score: 2, Insightful) by Anonymous Coward on Thursday October 12 2017, @11:13PM
I
am
passing someone. There's someone in the right lane going 55. I'm going 65 and want to pass them. I want to go 75, and I think it would be perfectly safe to go 75, but cops will get me if I go more than about 2 miles over the legal limit of 65, so I won't go faster than 65.
Meanwhile there's someone behind me who wants to go 85 and is having a temper tantrum like a 2 year old that I'm in the left lane in his way. He's so crazy right now he doesn't see whether I'm passing someone or not. He's blinded by rage and endangering us all and like all people having an angry outburst wants to blame other people instead of his own misbehavior.
(Score: 2, Touché) by Arik on Thursday October 12 2017, @11:22PM
And If you really must do 90+, I'll happily move over and let you past - just as soon as I complete what I'm doing so it's safe to do so.
Only thing that pisses me off is jackasses that won't wait for that and endanger everyone trying to pass on the right, while speeding, and close to other vehicles. That's really not cool.
If laughter is the best medicine, who are the best doctors?
(Score: 0) by Anonymous Coward on Friday October 13 2017, @08:45AM
Yes people shouldn't be hogging the passing lane if there's a perfectly empty lane beside, nor should they be going slower than other traffic beside if they're in the passing lane.
BUT a bigger (and as common if not more common) problem are the asshole tailgaters who do dangerous stuff because they don't want to wait for me to pass the other traffic even though:
1) I am actually in the process of passing slower traffic
2) I am at or even a bit over the speed limit.
3) I will move aside once I'm safely past the slower traffic ( cutting right in front is not safe even if the other vehicle is slower)
Those assholes smugly insist that just because I'm in the passing lane and traveling slower than they want to it means I must move aside.
But that's BULLSHIT. It is FAR WORSE for traffic flow if everyone traveling at the speed limit in the fast lane has to slow down to move into the already packed slower lane (slowing it down further or worse- causing "traffic jam waves") just because a few tailgaters behind want to go way faster than the speed limit.
(Score: 2) by NewNic on Thursday October 12 2017, @11:21PM (7 children)
And how often are the driving at the speed limit, as indicated by an optimistic speedometer? Many speedometers read 3-5mph above actual speed at 50+ mph. Regulations appear to mostly allow -0% to +(10% + ~5kph), so at 55mph, the speedometer could read ~65mph.
If they are in a jurisdiction where the passing lanes are just that: for passing, then they should pull over when not overtaking or following another vehicle, irrespective of speed.
lib·er·tar·i·an·ism ˌlibərˈterēənizəm/ noun: Magical thinking that useful idiots mistake for serious political theory
(Score: 2) by Arik on Friday October 13 2017, @02:04AM (6 children)
If laughter is the best medicine, who are the best doctors?
(Score: 0) by Anonymous Coward on Friday October 13 2017, @03:30AM
uh, it doesn't work that way. If you're really worried about it, get a GPS speedometer app for your phone. Chances are, at ~50-70 mph, your speedo reads about 1-3 MPH higher than GPS speedo will read.
The car mags periodically do stories about just this, as does Consumer Reports.
At least in the US, potential liability for having a speedometer indicating less than actual speed is...huge.
(Score: 1, Offtopic) by tangomargarine on Friday October 13 2017, @03:52PM (3 children)
Speedometer readout isn't reliable 100% of the time. For example, my car gets rather bad traction in the winter, even with my winter tires on, and when I'm spinning my wheels on ice/snow at an intersection to get going, I've had the speedometer climb to 20mph before I actually start moving. So presumably it measures wheel rotation or something rather than actual velocity. Plus, can't your speedometer readout be off if you have the wrong size of tires mounted? Because the diameter is screwed up so the measurement is based on an assumption with drift from expected values.
I've never looked it up but I imagine the problem of how to precisely measure your speed without GPS is a pretty interesting one mathematically. Differentials must be involved somehow? I really sucked at advanced math :P
(2009 manual Toyota Corolla)
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 2) by Arik on Friday October 13 2017, @06:07PM (2 children)
That's exactly correct. Which means that the only time it's inherently inaccurate is when, as you described, you lose traction.
Other than that, it's a matter of calibration. As someone else already mentioned, it's actually illegal for it to be calibrated too low (i.e. to show 49 when you're actually doing 50) but it's not illegal for it to be somewhat too high (if it says you're doing 52 when you're doing 50, that's just fine, legally.) This means that when you buy a car it's expected to be calibrated too high. Test it with a stopwatch on a nice flat stretch of road and you can get a pretty accurate picture of exactly how high it is. Radar signs and GPS are other instruments that can be used to compare. The effective calibration changes slowly as your tires wear and of course quite quickly and drastically if you put on new tires of a different size, so it's necessary for the adjustment to exist.
"I've never looked it up but I imagine the problem of how to precisely measure your speed without GPS is a pretty interesting one mathematically."
Nah, it's dead easy, simple. Velocity=Distance/Time
You need a relatively straight flat bit of road with known marked lengths. These are widely available. You get up to a given steady speed per your speedometer, click the stopwatch as you pass one marker, click again as you pass the second. If it's a one mile section, and it took 60 seconds, that's 60 miles per hour. (Sub kilometres if that's what you use, it works out just exactly the same regardless of unit.)
1m/60s=Xmps
but we don't actually want to know miles per second, we're looking for miles per hour, and it's going to be easier to do the conversion here than later, so it's 3600 seconds/hour of course. I'm using miles but if you prefer k just substitute it consistently and the formula works exactly the same. For that matter you can use it for inches per week or parsecs per season, it's the same formula. Anyhow.
1m/(60/3600)h simplify to
1m/(1/60)h
60mph
Of course that's the easiest case, what if it isn't 60 seconds, but something odd, like 57?
x=1m/(57/3600)h simplify to
x=1m/(63r9/57)h
x=63+(9/57)mph
or alternatively simplify to
x=1m/(.95/60)h
x=63.1578947368... (the same dang thing.)
If laughter is the best medicine, who are the best doctors?
(Score: 2) by tangomargarine on Friday October 13 2017, @06:22PM (1 child)
No, I mean difficult for the engineers who design the car. The car has to measure speed without using visual cues or the outside world at all beyond the tires.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1) by Arik on Friday October 13 2017, @06:36PM
What internal sensor that drives the speedometer actually measures is effectively the rate of rotation of the wheels. Multiply that by the circumference of the tires to get your actual velocity. (And this is why whether it's the old-fashioned cable-driven speedometer or some new digital sensor there still has to be a way to calibrate it for the actual circumference of the tires in use.)
Velocity = Rotations_per_time_unit multiplied by Tire_circumference. So 60rpm with tires 2m circumference means 120m/m or 2m/s.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by NewNic on Friday October 13 2017, @05:45PM
Not hard, correct.
How many people actually do it? Very few.
lib·er·tar·i·an·ism ˌlibərˈterēənizəm/ noun: Magical thinking that useful idiots mistake for serious political theory
(Score: 0) by Anonymous Coward on Friday October 13 2017, @02:43PM
No they are not in the right. Most states require you to move over to allow faster traffic to overtake you. THIS INCLUDES IF THEY ARE SPEEDING.
That's why you see signs saying slower traffic MUST keep right.