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Comment by pleb_nz | Hacker News Reader

I couldn't watch the video so can't comment directly on this case but it boggles the mind how close people follow others on the road.

The distance you have between you and the car in front on you is one of the only safety zones you can control on the road. People should cherish it and let it blossom into wide open space.

You often have no control over the left, right and rear. Why would you want to take away that front space as well?

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Can remember there were campaigns in my country in the 90's to increase distance between cars. The rule was to count 1001 1002 1003, so basically you should have a 3 second gap to the car in front. Not sure if it worked, but apparently it made an impression on me, so I constantly count 1001 1002 1003 when driving on roads with a higher speed limit.

You basically can't, realistically, do that in dense city highway driving, which looks like what this is. Like, we still say the driver who hits the back is "at fault" in these kinds of pile-ups but it's entirely a "there, but for the grace of God, go I" situation. They were just unlucky. 99% of drivers on that road drive the same way they were, and the ones who don't are probably driving in a way that makes things less safe.

In several countries in Europe they occasionally paint markings on the road (chevrons or dots or similar) with a sign like "Keep apart 2 chevrons". Some places have electronic speed limit signs to reduce the maximum speed in heavy traffic, which reduces risk and improves flow.

https://www.alamy.com/stock-photo-keep-apart-2-chevrons-moto...

(Obviously we can't tell the speed of the cars in the photo, but if it's the standard speed many drivers are still ignoring it.)

That's a UK motorway, so assuming the national speed limit applies they'll be travelling at around 70 mp/h.

There is very heavy traffic on both sides, so it wouldn't be unusual for the actual speed to be 50mph, 40mph or even less. The second nearest car is braking, and there's a "Queues Likely" sign a little further -- I found the place:

https://www.google.com/maps/@53.3015568,-2.722796,3a,75y,235...

StreetView gives a much better impression of the chevrons; the Alamy photo has an unusual choice of lens. The "M56 B 45.0" [km] milepost is way ahead of the chevron sign.

Sounds like a case for gap cameras similar to speed cameras.

Oh the money that could earn.

They'd have a revolt on their hands in short order, around here, and I suspect in most places. You can't handle enough traffic on the parts of our highways that go through the city, while maintaining the kinds of gaps that would be necessary to avoid these sorts of wrecks (well, the later pile-ons, anyway). Commute times would shoot up and areas that don't usually experience congestion would become intolerable around rush hour, if people really started leaving that much space, consistently.

Which is, perhaps, one of many arguments against having so many people on the roads to begin with, but that's what we have.

> You basically can't, realistically, do that in dense city highway driving, which looks like what this is.

Yeah you can.

The maximum carrying capacity of a single lane of highway traffic is around 1900 cars per hour (that is from real-world measurements of what human drivers can actually achieve). At 70 mph that is 194 feet per vehicle. Even assuming something like a 20 foot long F250 or something that leaves 174 feet of spacing between vehicles. Which is nearly 9 vehicle lengths and nearly 2 seconds of room. Up until you hit that point you're not impeding any traffic flow by adding more space. Almost nobody in this video is leaving that much room.

What causes traffic congestion and causes that 1900 vehicles per hour number to be that small is the people who are tailgating and when someone brakes everyone behind them has insufficient following distance and has to brake harder and harder until you've got vehicles nearly stopped on the freeway and have formed a traffic compression wave (if you haven't just created an accident and snarled traffic even worse).

No, you generally shouldn't drive that anomalously. A driver will pass you and insert themselves in front of you. You will fall back to create distance. Another driver will pass you and insert themselves in front of you. You create constant aggravation and churn around your car.

Source: I spent several months last year helping someone learn to drive in the Bay Area, and they insisted on leaving the recommended gap between cars as they prepared for their driving test.

That doesn't matter. And if you're not in the left lane usually people merging in front of you are heading for the "fast lane" (which is typically even more congested and slower) or heading for the exit lane. Just let them go on their way, into and just as rapidly out of your life.

And if you don't let yourself feel "aggravation and churn" then people will just merge into and later leave your lane and it just becomes normal driving without any ego involvements.

Source: the past 30 years of driving in Seattle traffic that I've done where I've stopped being a tailgating idiot and opened up more space and stopped caring about people "cutting me off".

Churn is not a feeling of your ego. Churn is the physical movement of cars on the road that creates numerous additional opportunities for collision.

100 people merging into 170 feet of space in front of you[*] is dramatically safer than 1 person trying to squeeze their way into the 20-30 feet of space you're leaving in front of you when you're tailgating.

[*] not all at the same time...

if they do, so what? even if 10 people cut in front of you, with a 30 minute drive, how much time are you really losing? 50 seconds?

They taught this to me in driver's ed 15 years ago, just start counting when you go past a sign or something.

The rule actually works great where I live (a rural area) but if I wander over towards chicagoland I will be punished with constant cutoffs. Also there's too many cloverleafs over there jeeze.

When you leave adequate space (especially) in city driving, another driver will always occupy that space. You back off to create more space, another drive enters that space. Rinse, repeat. Source: Boston driver.

Often true. And that's OK!

But with enough cars, theoretically it’s possible that you’d never reach your destination, run out of fuel, stop suddenly and get hit from behind…

Source: South Bay driver. I was going to say that but was sure I will find a similar comment. I start my day by trying to be a safe driver but as they drive progresses and more and more people jumping in the free space in front of me, I eventually change the mode to not be risky but don't allow space for others.

Re not watching video: This is the most crowded road, after a downhill slope, in a major metropolitan, after a mile of bridge driving, reaching a reduced visibility tunnel, with one way traffic, and 5+ lanes.

There's too much traffic. It backs up into the streets, before this bridge + tunnel regularly. The speed is already restricted.

aside, people drive somewhat close in the bay area, but also in my experience it's so much worse in both LA and in Austin, and in TX so many of them are 6000lb Ford F150s.

In LA if you try to have distance someone will fill in the spot. I've experienced this in the Bay too. While I agree with many of these comments about people driving too close, I think it ends up being too simple and naive to real world conditions. This behavior tends to be true in any major city but not so outside.

Yeah I understand the "fill the spot" issue all too well. This is a behavior that our police/legal system is failing to address adequately. The emergent behavior is not the safe, legal, or even optimal behavior for traffic flow/reduction (afaik). But as I've observed in America, it's more about getting 1 car ahead of others than it is about having optimal outcomes across a large proportion of all traffic.

I have a hypothesis that this is another emergent pattern. I drive a lot between WA, OR, and CA. One thing I notice is that in OR I can easily pass people AND that if I'm in the left lane approaching someone there's a fairly high likelihood that they move right. Maybe 1 in 10 people don't move. But once I hit California I end up zig zagging much more, passing people who are in the left lane going below the speed limit (especially in central California). But I don't think the probability changed, but rather the population. Oregon is easier to rive in than Washington which is easier to drive in than California. I'm pretty sure this is just a small number of bad actors who are a constant percentage and their effects scale (probably also providing a feedback loop). I try to slightly combat this by calling the left most lane the "passing lane" rather than the "fast lane." A lot of people treat the left lane like kids treat lightup shoes: they think it makes them go faster.

And don't get me started on elephant racing. I frequently wonder the economic and environmental impact of just this singular type of event in central California.

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