My Autopilot never freaks out when people cut in front of me. I love it. It just gentally slows don't and never over reacts. I usually run 2 secs back.
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What is this headlight calibration setting mean? [not headlight, follow distance]
- Thread starter wmo168
- Start date
stopcrazypp
Well-Known Member
That sounds like a lot like the justification used by tailgaters, when plenty of tests show that tailgating essentially saves you no time in travelling. If you are keeping up with the flow of traffic, having a larger following distance would not put you further behind beyond that extra follow distance (which results in literally seconds of delay in the overall trip). This is because there won't be traffic trying to get in front of you, if you were in the proper lane for your speed.
Even if the car cutting in is going significantly faster than the car in front of you, they quickly will lose patience with the car in front of you, and will move to another lane, in which case you can accelerate to close the gap after they leave your lane.
Yep, tailgating doesn't help traffic flow, because it gives you less reaction time; so inevitably there are lots of micro-braking events, which cascade back and eventually results in someone stopping, due to nothing at all but someone did a tiny braking due to inattention. The best strategy is smoothness and never stopping. Sacrificing a little larger gap to the car in front of you, in order to be smooth pays off in everyone driving faster. Dive bombing gaps, and forcing the car behind to do a micro brake can cause a cascade of braking. It's terrible and causes backups out of thin air. Robodriving will be a huge boon to eliminate traffic jams. Unfortunately, humans intuitively do the wrong thing to avoid backups and jams.
rpiotro
Active Member
When the roads are congested, large gaps will cause fewer cars to pass a given point. There will actually be less traffic flow.
Actually research shows that it's better to have larger gaps than tailgating, since tailgating leads to more braking events, which can lead to stoppages and backups. Larger gaps lead to smoother overall flow, and fewer stoppages. Even though, intuitively it seems like smaller gaps mean more cars pass a point in a given time, it doesn't since there's more likely to be stoppages.
Actually, research also shows that large gaps in high traffic areas will increase slow down as you attempt to recover following distance as people continuously move in front of you.
As with anything, balance is key. At full speed limit with a road that is below capacity a 3 second follow wont really effect much. At reduced speeds as traffic exceeds the roads capacity increased follow will further increase the slowdown as you enable a surge of cars to be added to that lane which further increases the excess load on that lane.
As with anything, balance is key. At full speed limit with a road that is below capacity a 3 second follow wont really effect much. At reduced speeds as traffic exceeds the roads capacity increased follow will further increase the slowdown as you enable a surge of cars to be added to that lane which further increases the excess load on that lane.
stopcrazypp
Well-Known Member
I already addressed that point, people continuously cutting in front of you essentially doesn't happen if you are keeping up with traffic. The car next to you can see that you are going at the same speed as the car in front and cutting in front of you gains them nothing. Even if they miss that, as soon as they cut in and see their own speed drop, they will quickly leave the lane (in which case you are back to square one).
If on the other hand traffic in all lanes are going the same speed, they simply won't be able to pass you because the car in front of them would be blocking them.
I have observed this in both high traffic (stop and go) as well as moderate traffic at speed. The key is your car is in sync with the car in front (not giving the impression you are falling behind the car in front).
We are taking about the legal 3 seconds, not talking about huge deliberate gaps.
Not according to actual research. Here's a link to the study @KenC was referring to:
Stop Tailgating, It Only Makes Traffic Jams Worse
New research from MIT shows that leaving a little space between the cars in front of and behind you can make traffic jams disappear almost completely.
www.popularmechanics.com
Tailgating is a rather loose term than can mean anything from an inch from the car in front to 2.99 seconds behind depending on what you consider it to be. That being said I am not saying its best to bump draft the car in front so nobody can ever get in front of you, that's dumb. What I am saying is that leaving 3 seconds of follow while in traffic will increase slowdowns. By traffic I mean any time the flow of traffic is below limits by the way. Meaning the road has more people on it that the flow can support.
That study also mentions absolutely nothing about a 3 second gap and everything about maintaining a flow and equal distances in front and behind which is exactly what I try to do and recommend attempting to do. As the little graphic also shows, attempting to leave following distance in front that is larger than anyone else in the lane is a major cause of heavy slowdowns.
Also, its usually referred to as the 3 second rule because its rarely actually a law. That's definitely not a law in California or Nevada. I'm not even aware of any state where it is an actual law now that I think about it.
That study also mentions absolutely nothing about a 3 second gap and everything about maintaining a flow and equal distances in front and behind which is exactly what I try to do and recommend attempting to do. As the little graphic also shows, attempting to leave following distance in front that is larger than anyone else in the lane is a major cause of heavy slowdowns.
Also, its usually referred to as the 3 second rule because its rarely actually a law. That's definitely not a law in California or Nevada. I'm not even aware of any state where it is an actual law now that I think about it.
stopcrazypp
Well-Known Member
My point is I dispute that. I don't see that happen even in stop and go traffic, as long as the car is in sync with the car in front (meaning it's not constantly varying the speed relative to the car in front).
The red car is simulating a car braking/slowing rapidly in response to stimuli, making the car significantly slower than the car in front. It's not that gap that is the issue (if the car was following the car in front at same speed it wouldn't be an issue).
The issue is the cars behind are too close to smoothly respond to slowdowns in the front, so it causes a cascading effect. That's exactly what the 3 seconds is designed for (it's based on reaction time)!
The 3 second rule is not explicitly put in the law because there are circumstances that you need longer than 3 seconds of gap (for example in poor weather).
There is a law against tailgating however:
"The driver of a motor vehicle shall not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of such vehicle and the traffic upon, and the condition of, the roadway."
https://law.justia.com/codes/california/2017/code-veh/division-11/chapter-3/article-2/section-21703/
If you look at ticket fighting sites, "reasonable and prudent" as determined in traffic court is essentially the 3 second rule (plus whatever reasonable longer gap given road conditions):
21703: Declaration Strategy 1 – TicketAssassin
21703: Declaration Strategy 2 – TicketAssassin
Basically you can successfully fight the ticket if the officer references only car lengths or feet in citing you for a ticket (as that's not enough info to determine seconds of following distance), but not if officer establishes enough facts to determine your following distance is significantly less than the 3 seconds referenced in the driver handbook (for that they will need not only the distance but also the speed of both cars).
Nevada uses a 2 second rule instead (see page 38 in driver handbook, it's more exactly 2-4 seconds or more, but 2 is the minimum), which is probably why you never see people using 3 seconds in your location.
https://www.dot.nv.gov/home/showpublisheddocument/112/636178632858000000
Your state law also uses "reasonable and prudent" which I suspect, like CA is also determined by the rules in the driver handbook if you go to traffic court for such a ticket.
NRS: CHAPTER 484B - RULES OF THE ROAD
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