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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

#351

Post by necovek »

yial wrote: post #66
jjice wrote: post #42

Earlier quoted context omitted.

I have a friend who would also follow too closely to the cars in front and got one of these. Her rates went up and she eventually got into an accident (no injuries to anyone) because she would follow too closely and still break too hard. Now she still has the machine, still follows too closely, and still breaks too hard in her new car... Good it worked for you though!

A cousin of mine is abysmal to drive with as a passenger. He follows too closely to the car in front of him, regardless of lane / speed. He will slow down, follow closely, and then aggressively pass. Repeating ad nauseam. No smooth maintaining of speed and nice passes as able without slowing down. Surprisingly, his accidents have mostly seemed to involve gas pumps, barriers, and other obstacles at low speed.

I believe inattentive driving correlates more with accidents than things like hard braking, and might be the leading cause of hard braking too (inattentive driving will lead to following distance being reduced too as you are not watching for traffic well ahead and to the side of you).

At the same time, passing on regular intercity road can have the risk reduced (up to a point) by making the passing quicker, by spending less time in the oncoming traffic lane ("aggressive passing"). It certainly does not help with comfort, though.

So perhaps your cousin is a very attentive driver who drives aggressively? That might still only make him an "average" driver (I've had such drivers almost get others in an accident in front of me), but I think it's a balance that needs to be struck, otherwise most would tune out and not be ready for emergencies.

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

#352

Post by CarVac »

pinkmuffinere wrote: post #342
kqr wrote: post #165

Earlier quoted context omitted.

Not only are you less likely to crash -- you're less likely to cause a crash ten cars behind you. This diagram changed how I think about following distance: https://entropicthoughts.com/keep-a-safe-following-distance

I find this diagram _incredibly_ hard to read. I’m pretty sure I understand the phenomenon he’s describing — without safe following distances, car n+1 must break more aggressively than car n in order to avoid a collision, so given a long enough chain of non-safe followers, a collision is guaranteed. But either I am dumber than I’d like, or that plot is terrible.

The choice of X and Y axis are absolutely terrible.

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

#353

Post by yial »

toxik wrote: post #87
yial wrote: post #66

Earlier quoted context omitted.

A cousin of mine is abysmal to drive with as a passenger. He follows too closely to the car in front of him, regardless of lane / speed. He will slow down, follow closely, and then aggressively pass. Repeating ad nauseam. No smooth maintaining of speed and nice passes as able without slowing down. Surprisingly, his accidents have mostly seemed to involve gas pumps, barriers, and other obstacles at low speed.

This is left lane driving policy. I am like this, and I was not at first. What makes you drive like this is rush hour traffic. "Move up the lane or move out of the lane" is the sentiment, basically. As others have noted, it is essentially an adversarial process. If you drive nice, people cut in front and you're unable to drive nice to both those behind you and in front.

I don’t think what you’re describing is quite the same thing.

At least I hope not.

More concrete example:

He will be going 65 mph in slow lane. Come up on a car. (Left lane empty). Slam on his brakes. Follow them at 50 mph for 1-3 minutes Pass, flooring it, if he stays in the left lane he’ll keep going until he now tail gates a car in front of him- usually with large speed variances.

The amount of traffic on the road doesn’t matter. It can be 3 cars and he will drive this way.

I’m not talking about trying to drive through major city rush hour traffic.

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

#354

Post by yial »

michaelt wrote: post #188
yial wrote: post #89

Earlier quoted context omitted.

I do drive in the slow lane frequently - and this still occurs. (My go to is to set my cruise 6-9 mph over the speed limit, if passing to smoothly pass and get back over, and spend as much time as possible in the slow lane. ) However - I will say most of the roads I’m on are 2 lanes of traffic. I will have to experiment and see if this doesn’t occur when there are 3 or 4 lanes.

> I do drive in the slow lane frequently - and this still occurs. One part of your post was about people passing on the right. People won't do that if you're in the rightmost lane.

Apologies - you’re correct. I should have been more specific in that I was referencing the scenario of:

I’m car 2, waiting to pass car 1. (Who’s passing a car slowly ). I have safe following distance.

Car 3, passes me in the right lane, and then either follows car 1 closely, or, quickly passes them on the right. (Usually as they’re in the process of moving over, causing them to then swerve back).

I realize I communicated this in an absolutely abysmal fashion.

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

#355

Post by Uvix »

crest wrote: post #291
rootusrootus wrote: post #274

Earlier quoted context omitted.

> On I-5 near Woodburn, OR The section of I-5 between Portland and Salem is absolutely psychotic, and I have never been able to reason out exactly why . It consistently has a left lane jammed with angry people going at or below the speed limit, a fairly normal center lane filled with cruisers, and a mostly empty right lane with the occasional big rig and regular very-high-speed cars expressing their frustration with…

It's wild to me that it's allowed and accepted to overtake on the right on US highways.

It's generally not allowed, but that doesn't stop people just like the speed limit doesn't stop them.

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

#356

Post by yial »

girvo wrote: post #177
yial wrote: post #89

Earlier quoted context omitted.

I do drive in the slow lane frequently - and this still occurs. (My go to is to set my cruise 6-9 mph over the speed limit, if passing to smoothly pass and get back over, and spend as much time as possible in the slow lane. ) However - I will say most of the roads I’m on are 2 lanes of traffic. I will have to experiment and see if this doesn’t occur when there are 3 or 4 lanes.

The idea of cruising 15km/h over the limit is absolutely crazy to me. That will get you 3 points and a minimum $500 fine here. We have "average speed zones" too!

There are different norms in the U.S. - where I am- generally 5 mph over the posted speed on side roads, and ~9 over on interstates / highways.

You are very unlikely to get stopped for either of those.

Another commented using an example of 8 and 9, but here it’s “9 you’re fine, 10 you’re mine”.

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

#357

Post by Klaus23 »

dietr1ch wrote: post #261
rconti wrote: post #172

Earlier quoted context omitted.

Is it one of those cars that alters the brake boost depending on circumstances? That drives me nuts. When you put x amount of force into the brake pedal, you should know you're going to get y amount of deceleration. Don't double the brake boost just because you decided it's an emergency due to some opaque criteria.

> Is it one of those cars that alters the brake boost depending on circumstances? No, it's just breaking a bit too hard for you while the panel beeps and has scary red lights pop (that you'll have a hard time reading).

If you are referring to the alert stage of the emergency braking system, triggering it should be rare if you drive reasonably well. It is also most likely a situation in which you could benefit from a little more braking force.

If you decide to swerve, the additional weight at the front will help you to initiate the turn, and good systems will then reduce the braking force at the right moment to give you the most traction when cornering.

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

#358

Post by Gigachad »

Someone1234 wrote: post #28

This type of research is highly valuable but too rare; this is generally because of how we view Road Accidents at a core level: - Road Accidents: "A driver caused this, let's determine who, and find them at fault." - With Air Accidents: "The system caused this, let's determine which elements came together that ultimately lead to this event." The first is essentially simplifying a complex series of events into somethi…

Because for air travel we pre filter out the morons who are drunk, untrained, scrolling facebook, etc. Any incident left is overwhelmingly more likely a systems issue. For a road incident, the most likely cause was just one driver was violating one or more rules. The only system failure was not canceling their license beforehand.

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

#359

Post by CGMthrowaway »

crazygringo wrote: post #340
carshodev wrote: post #338

Earlier quoted context omitted.

If you actually want the safest option then you should merge all the way right and keep slowing down. Noone is going to merge right if they are trying to go faster, they will only do it to get off the offramp. Meaning the gap will reopen as people exit through the offramp or merge left into faster lanes. If you choose to go in the fastlane in traffic you should understand that it will have people who do not care abou…

> If you choose to go in the fastlane in traffic you should understand that it will have people who do not care about the following distance as much and are just trying to go as fast as possible. It's not about choosing to go in the fast lane. It's about the fact that in heavy traffic, you have no idea which lane will be fastest, because they're all heavy and which one is fastest keeps switching. > I have found that…

This is a long thread of people talking past each other. The bottom line is simply this: if you want to drive with a larger-than-average following distance (call it whatever you want, a safety buffer, a "proper" following distance, the point is it is a distance less than the average following distance of the other drivers on the road) then you have to accept that you will not be able to drive at the same speed as the other traffic on the road. It's physically impossible. It can be psychologically frustrating because you see all the cars around you moving at X mph but your self-imposed constraints mean you can only make way at (X minus Y) mph. But them's the breaks, no pun intended

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

#360

Post by necovek »

michaelt wrote: post #188
yial wrote: post #89

Earlier quoted context omitted.

I do drive in the slow lane frequently - and this still occurs. (My go to is to set my cruise 6-9 mph over the speed limit, if passing to smoothly pass and get back over, and spend as much time as possible in the slow lane. ) However - I will say most of the roads I’m on are 2 lanes of traffic. I will have to experiment and see if this doesn’t occur when there are 3 or 4 lanes.

> I do drive in the slow lane frequently - and this still occurs. One part of your post was about people passing on the right. People won't do that if you're in the rightmost lane.

Well, if there is an emergency lane to the right... it actually happens quite a bit around here.
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