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Hard-braking events as indicators of road segment crash risk

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Re: Hard-braking events as indicators of road segment crash risk

#501

Post by angiolillo »

lordloki wrote: post #484
closewith wrote: post #444

Earlier quoted context omitted.

> The issue is that when you slow down, you’re (a) creating ‘turbulence’ in the traffic flow with increased speed differential between cars and increased lane changes, which increases accident risk for everybody, and (b) it’s not even solving the problem because you still perpetually have some impatient driver wedging themself in directly in front of you, deleting your buffer zone. That's very obviously not true. Slo…

Slowing down on a busy highway does not reduce turbulence at all, it add chaos and unpredictability to the system. Once car suddenly slowing down to create a buffer zone causes the car behind to slow more and more and can often lead to a stop further back. This has been proven time and again on closed loop systems studying highway traffic flow. They are known as "phantom" traffic jams or shockwave traffic jams. Examp…

> Slowing down on a busy highway does not reduce turbulence at all, it add chaos and unpredictability to the system. Once car suddenly slowing down...

I agree that slowing down "suddenly" causes turbulence. However, slowing down *gradually* allows you to build up a safety buffer which in turn allows you to avoid slowing down suddenly.

Re: Hard-braking events as indicators of road segment crash risk

#502

Post by sfn42 »

lordloki wrote: post #487
ehnto wrote: post #326

Earlier quoted context omitted.

Slow down a bit to create another buffer. You can even do this before they have merged, as part of the bit where you allow them to safely merge. I think if you reflect a bit you'll find you are being the same kind of person as them, if you are getting angry that you have to slow down and give up space for someone else. I understand some people can be aggressive though, that can be frustrating regardless of the outcom…

-Slow down a bit to create another buffer. Now you've just created a shockwave traffic jam.

No. That happens when people drive too close to each other and brake. Not when you let off the gas slightly to maintain a gap which prevents this exact thing.

The entire reason this happens is because 98% of people are morons who drive up the next guy's ass. If everyone kept a proper distance it wouldn't happen at all.

Re: Hard-braking events as indicators of road segment crash risk

#503

Post by maerF0x0 »

gwbas1c wrote: post #494
maerF0x0 wrote: post #268

Earlier quoted context omitted.

In my place, there's a significant group of drivers who will ride your tail too close hoping you'll move over so they can get 1 car ahead. And if they see more than 0.9 car length in front of you they will do what they can (weaving other lanes) to try and get into that space, 1 car ahead of you. As far as I can tell it's pure selfishness and competitiveness. Their desire isn't to cooperate and arrive it's to take fro…

That's (the tailgaters) reckless driving and very illegal. It's a symptom of poor traffic enforcement.

I definitely agree there is poor traffic enforcement here. In fact our cops are basically potatoes.

Re: Hard-braking events as indicators of road segment crash risk

#504

Post by maerF0x0 »

Spooky23 wrote: post #500
crazygringo wrote: post #331

Earlier quoted context omitted.

I don't think you're understanding. The point is that 20 people in a row will take advantage of your buffer to slow you down again and again and again, which makes you get to your destination later... because they're being selfish to get somewhere faster, and you're not so you get to where you're going slower . We're not talking about where they're changing lanes to take the next exit. We're talking about where your…

You’re the problem because of the way you are thinking. You don’t own the asphalt in front of you. You’re angry because in your mind you do, and you feel righteous about it. That’s why you are casting a moral judgement about them. The most efficient throughput of the road system is not for people to “politely” queue up for 5 miles. People should be utilizing the rod and merging in an orderly manner. By adopting some…

> You don’t own the asphalt in front of you.

Correct, but you _need_ the asphalt in front of you for both safe driving and also to avoid cascading hard braking events. I also don't own the asphalt under me or behind me too, so it's kinda a silly statement tbh.

This youtube talks about it: https://www.youtube.com/watch?v=iHzzSao6ypE

Re: Hard-braking events as indicators of road segment crash risk

#505

Post by alt227 »

b40d-48b2-979e wrote: post #467
alt227 wrote: post #457

Earlier quoted context omitted.

Why jump to cities? Low speed traffic in cities is not the main location of car collisions. The main issue is highways and rural roads.

The main issue is highways and rural roads. Source? I'd wager most accidents happen where the most people are. Cities.

It seems we are talking about different things.

The majority of car collisions happen on urban roads where the majority of cars are.

The majority of fatal collisions occur on rural roads, where vehicles are travelling faster.

I live in the UK.

https://www.simplyquote.co.uk/insights/where-do-most-car-acc...

Re: Hard-braking events as indicators of road segment crash risk

#506

Post by 1970-01-01 »

My gut tells me there's also another signal in the data. Soft braking events under conditions that call for acceleration. E.g. driver cannot process a highway merge in real time, so they slow down to have more time to think about what they should do next. Go!

Re: Hard-braking events as indicators of road segment crash risk

#507

Post by alt227 »

ses1984 wrote: post #491
alt227 wrote: post #460

Earlier quoted context omitted.

IMO there is nothing worse than drivers on highways who think that by leaving bigger gaps and slowing less rapidly they are 'smoothing' out the traffic and helping the whole road run better. You are not, you are just making the whole road run slower and taking up more space for yourself on a crowded road.

I think there's nothing worse than drivers who feel entitled to go fast at the expense of everyone else's safety.

Yeah, I agree fully with you on that point.

However purposely making the cars behind you break more and causing more compression further back just so that you can avoid the compression in front of you is madness.

Re: Hard-braking events as indicators of road segment crash risk

#508

Post by 1970-01-01 »

killjoywashere wrote: post #328

Table 1 and Figure 4: why are the Virginia controlled-access highways different? That population stands out in a way that smells like either a cultural difference or a policy difference. I spend most of my time in California, have lived in SoCal and NorCal, and I spend a fair chunk of time driving around Virginia. My guess is that there's something fishy with the Virginia data being reported. Because if there is anyp…

Speeding in VA just as you would in all other states literally becomes a criminal offense if you're caught. The data is reflective of that.

Re: Hard-braking events as indicators of road segment crash risk

#509

Post by closewith »

lordloki wrote: post #484
closewith wrote: post #444

Earlier quoted context omitted.

> The issue is that when you slow down, you’re (a) creating ‘turbulence’ in the traffic flow with increased speed differential between cars and increased lane changes, which increases accident risk for everybody, and (b) it’s not even solving the problem because you still perpetually have some impatient driver wedging themself in directly in front of you, deleting your buffer zone. That's very obviously not true. Slo…

Slowing down on a busy highway does not reduce turbulence at all, it add chaos and unpredictability to the system. Once car suddenly slowing down to create a buffer zone causes the car behind to slow more and more and can often lead to a stop further back. This has been proven time and again on closed loop systems studying highway traffic flow. They are known as "phantom" traffic jams or shockwave traffic jams. Examp…

Yes, and they are caused by sudden decelerations which are the result of many factors, including driving too fast for the conditions, roadway, and traffic, and tailgating.

> Slowing down on a busy highway does not reduce turbulence at all,

The only thing that reduces global turbulence reliably on any roadway is reducing speed. All the simulations and real-world implementations show this. It's unambiguous and uncontroversial, except that it requires drivers to slow down, which is politically untenable in many jurisdictions.

Re: Hard-braking events as indicators of road segment crash risk

#510

Post by littlestymaar »

alt227 wrote: post #457
littlestymaar wrote: post #397

Earlier quoted context omitted.

Or “design cities to be less car centric so we can keep the antisocial drivers out of a car”. It's definitely a system issue.

Why jump to cities? Low speed traffic in cities is not the main location of car collisions. The main issue is highways and rural roads.

“Highways” and “city” aren't incompatible, quite the opposite: most of the traffic on highways is commuting, in urban areas.
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