Do drivers who keep gaps in stop-and-go traffic worsen it? (2012)
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And that applies to stopping, where you should (IMO) have very little gap. For the exact reasons you mentioned.
I long ago gave up viewing driving as an adversarial activity. Slamming on the brakes means I'm not maintaining a safe distance or speed. Any pent up frustration or anger I harbor is reserved for the sap that caused the accident up ahead that slowed everyone down in the first place.
I've found that usually people who will cut in front of a gap accelerate pretty quick - after all, they're hopping lanes so they can do that. I rarely need to slow down for them, although occasionally some asshole will misjudge distance & speed.
I have no science behind this, but I've driven in enough places to notice that there are broad cultural differences in how people drive. I don't think the difference is just in the people. It's also in the civil engineering.
For example, some places are very consistent about having nice long on-ramps that give drivers plenty of time to negotiate a merge without too much hassle, and entrances and exits are always placed on the right-hand side. My impression has been that these cities tend to have very sane drivers. Fewer traffic jams, too.
Others have exits and onramps on both sides. The ramps are often short, and you might even have the occasional short ramp with a tight curve that forces drivers to enter the highway 15-20MPH below the speed limit. These cities force a number of perverse behaviors that make driving problematic. It gets slow drivers out of the right lane because that lane is downright frantic. It also actively places drivers who prefer to drive at wildly varying speeds in the left lane, so now you've got people trying to find their place from both sides of the road at the same time. These combine to encourage a lot of passing on the right, which further mixes drivers who like to go at different speeds across all the lanes. And all that jockeying begets further jockeying, since one starts to feel like they have to drive aggressively just to hold their own.
Against that kind of backdrop, which seems to be the way American cities actually prefer to arrange themselves, I do think that no amount of education or public awareness could ever fix it. You can't create an environment that actively punishes people for behaving how you want them to, and expect them to behave that way anyway.
I have personally witnessed the basics of this taught as part of a driver safety course, and most of the people who took the course at least made noises like they were surprised at some of the more intuition-challenging aspects.
I'd also make the argument that the people who stubbornly don't get out of the way of tailgaters are at fault for creating slow road conditions, and share the blame for a dangerous driving situation. If someone behind you wants to go faster, get the fuck out of the way. And it's not even my preference-- in WA and OR it's literally the law that slower traffic should move right, but I've never heard of anyone being ticketed for it.
Dumb people tailing and trying to go that extra 5mph are as much to blame for the danger as the people that don't get out of the way. And since they will be constantly forcing people to switch lanes, the outcome is the same except some idiot got their way.
So no.
I still do it, because on average I can keep a good gap in front of me, but I have a feeling that's a big part of why it seems like nobody does it.
In the Pacific Northwest, maybe 20% of drivers are trying to make any decision that will help them. Maybe another 20% are trying to do the best for themselves as long as it doesn't harm the global traffic state. The last 60% are checked out and are barely paying enough attention to not crash.
I won't, however, argue with your numbers. Tagging 60% in the "able to aim their car toward Bel-Square without hitting anything on the way" seems about right. And as you point out, it's the cause of much of the traffic woes of the Seattle area, not lack of road capacity. If everyone learned to merge smoothly, and realized it's not their $DEITY-given right to just randomly pick a lane to drive in, we could last another ten years before needing to add lanes.
Some useful practices I developed:
Don't look at the car directly in front of you. Stare through its windshield if possible to get an idea of what the car second in line is doing. If you can't see through the windshield, try looking at its shadow. And if you don't see a shadow, look under the car right in front of you: you should be able to see the first car's lights illuminate the pavement and guess what it's doing. When it's raining, that is especially easy since the pavement is much more reflective.
Also set your mirrors in such a way that creates a "single" mirror. Where the proximal end of your left mirror ends, the proximal (left) end of your cabin mirror begins. Where the distal (right) end of your cabin mirror ends, the proximal end of your right exterior mirror begins. This eliminates the need to look behind you every time you want to switch lanes. It doesn't eliminate your blind spot, merely moves it, but that's only a problem if someone is making a 2-lane change. That's usually pretty rare in heavy traffic.
Of course, all of these tricks don't work when others drive too erratically. If you don't gauge the distance between you and the vehicle right before you, others will 100% jump at the chance to cut you.
Yes! Also, when it's darker, you look for brake lights way ahead. That's also a marker for speed traps.
Tim Roughgarden has a fantastic book that's very satisfyingly deep, but succinct.
https://mitpress.mit.edu/books/selfish-routing-and-price-ana...
Additionally, when the gap is lessening because the car in front it stopped or at the slowest speed of the variable speed traffic, another vehicle inserting itself into this buffer can make you slow rapidly, thus negating the point of leaving a buffer to smooth out the variable traffic speed.
My compromise in a three-lane situation is to always favor the center lane in congested traffic, especially prior to an upcoming exit. If traffic starts to move, I can move left since after the exit, the missing cars will be starting to merge back in (and to the left, negating the advantage of the center). If traffic doesn't move, I tend to just maintain center lane.
Impatient, frequent lane changers always add risk to themselves and others because they're bouncing back and forth between left (the fast lane and the way things "should" be to them) and the right (which routinely frees up as people exit). They tend make it to where they're going faster, but I don't necessarily think it is worth the risk.
Edit: I also hate it when bicyclists blow through city traffic at 10-20 kmph relative speed. For some reason, I'm more afraid of accidentally hurting them.
Tangent: how about the drivers that think we should all be merging one entire mile before the merge point and therefore start straddling two lanes in an attempt to prevent passing in the empty lane?
We're supposed to use all the pavement and then zipper merge at the merge point. This would be even easier if traffic would be consistent about gaps.
What is really interesting to me is the math behind leaving extra space in moving traffic. I have to cross a major bridge every day (Vancouver, Lions Gate Bridge) which is often only one lane for my direction. A driver leaving 5 or 10 seconds worth of space impacts everyone behind them. 10 seconds x 350 cars means that one person leaving too much of a gap is actually creating an hour's worth of delay.
And nobody leaves a 5-10 second gap. That's huge. The DMV recommends something like 2-3 seconds.
10 seconds on a bridge is not unusual. They are normally people looking at the view.
The kids around here are taught to "Increase your following distance ... to four seconds in bad weather conditions." In Vancouver, that is a not-small amount of the year.
http://www.icbc.com/driver-licensing/Documents/drivers5.pdf
At 75kph (normal speed on a rushhour bridge) 4 seconds means an 80 meter (90yard) gap. If everyone left such a gap any city would grind to a halt.
Also, presumably they'll close the gap or leave the road at some point, at which time cars could (shouldn't) speed up and save their 8 seconds. But it's that kind of stupidity that causes the traffic waves anyway, to save 8 seconds.
At a stop light that has turned green all the cars do not go at once. They all proceed sequentially from first to last. If the line is long enough, and the light short enough, the last car cannot make it through. If all cars were to accelerate at the same time simultaneously like a train then many more cars would make it through the light. Of course this will never happen with human drivers.
I believe keeping a reasonable buffer in traffic helps prevent the above situation that I see occur at lights. The delay of this affect is repeated for each and every stop.
I think an excessive gap would make the flow worse in the way described in the article. I'm thinking there's a happy medium somewhere. Somewhere between the excessive gap of the one that wants to teach everyone the 'wisdom' of the gap and the hot-heads that want to drive over the person in front.
I know the theory, but people frequently and incorrectly state that emergent traffic jams are proof that leaving large gaps to smooth traffic behind you improves traffic flow. That to me this is an unacceptable leap of logic. Why are their no contrasting simulations showing traffic flow with and without these "smoothing" agents? Creating a simulation that has rolling traffic jams, introduce agents that disperse the traffic jam (can you actually disperse these traffic jams anyway? Again, not demonstrated in the story.) Has throughput increased? It's not a given that it has.
My concern is that the people who tried to do what I am saying only achieved negative results, so they did not publish. Regardless of my concerns, I believe this theory might be true. Which is why this is so frustrating!
http://www.slate.com/articles/life/transport/2011/10/rolling...
It is all about how many cars flow through a certain spot a minute. If you have space you have more time therefore creating MORE traffic behind you!
If I had a billion dollars this would be a Super Bowl Commercial and I would blast YouTube and FaceBook with ads.
Throughput is only one goal for traffic. One can see immediately that a minute of flow at 15mph is equivalent to a minute of stop/go traffic at 30mph equally divided. Similarly, a minute of flow at 15mph is less than a minute of stop/go traffic at 45mph. The latter is NOT the goal of a congruent traffic system because it will result in decreased safety. Eliminating gridlock is a priority for all traffic engineers.
The more important goal for traffic is safety. It is also immediately evident that constant, predictable traffic patterns result in lower accident rates than unpredictable changes like those found in stop and go traffic. Stop and go traffic encourages tailgating, aggressive lane changing, and aggravated driving.
The phrase "you have more space you have more time" does not imply "MORE traffic". It is actually the people driving with this type of mindset that create the traffic, not the person in front.
So the down votes are for the desire that people INCREASE the distance between them and the car inf ront when the speeds drop?