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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

#561

Post by carshodev »

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…

The fastlane is just another name for the leftmost lane, I am not talking about the one moving fastest.

Again we are not talking about the fastest lane here we are talking about the safest as the OP was concerned about following distance.

> That's exactly my point. Which is why you can be in the right lane, and tons of people from the slower lane will try to merge in front of you

If everyone merged right it would not longer be faster but people do not do this. In the right lane you can slow down as much as you want and never cause an issue so you can always make a gap. In any other lane if you slow down more than traffic you cause issues because people will then try and pass you from the right which is dangerous.

You are placing the burden of your forward following gap on the cars around you but that is a terrible way to drive. You need to be in control of yourself when driving, do not trust that someone is going to follow traffic laws, do not trust that they will go whatever way there turn signal says, do not trust that they will look over there shoulder before merging.

If YOU want a following gap then the only possible safe way to do this is to merge all the way right and slow down whenever someone merges in front of you. There is no other way to do it in heavy traffic. And YES you will have to live with the fact that you will be driving slower than the traffic around you. That's the trade you make if you choose to have a large following gap.

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

#562

Post by StillBored »

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.

Its not against the law in any US state (a quick search seems to back this up) to pass on the right. With one huge gotcha, it must be "safe" defined in various ways.

OTOH, most states have a stay right except to pass, slower traffic keep right laws.

Which means, that unless the person to your right is weaving through traffic, driving on the shoulder, or a few other bits of unsafe behavior, if someone passes you on the right your likely the one violating the law by not moving right when your not actively overtaking/passing someone.

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

#563

Post by maybewhenthesun »

apparent wrote: post #555
maybewhenthesun wrote: post #425

Earlier quoted context omitted.

You might be a bad driver and not even know it.

My decades-long impeccable driving record tends to indicate otherwise. I just don't drive as if I lived in the fantasy land where leaving a long follow distance means I have a lot of room in front of me. It doesn't. It means I get cut off, and the follow distance ends up being shorter than it would have been had I just been following at the same distance as all the other cars on the road.

It is possible of course that the highways you drive are just too busy and the max speed is actually set too high for how busy the road is. That happens more than you'd want because lowering the max of a highway is always an unpopular thing to, even if it's needed.

Still, I tend to find that people underestimate the danger of short distances. Often it's just better to accept a 100 cars going in front of you than to shrug off following someone at 1.5 seconds. It can go well for years because crashes are rare, but when you are in a crash you will be royally screwed when you don't have the reaction distance needed.

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

#564

Post by direwolf20 »

StillBored wrote: post #558
direwolf20 wrote: post #434

Earlier quoted context omitted.

That seems rather inefficient on an 8– or 16–lane road.

Why? If everyone followed the rules the lanes would segment into slowest on the right, with gradually increasing speed to the left and people moving between the lanes as needed to overtake. It would be far far far better than the chaos of having to move across all the lanes of traffic all the time because there are random campers driving below the speed limit in every single lane.

First, everyone switches right as soon as there's a gap in a righter lane, so lots of unnecessary switching. Second, the right lane is always full making it hard to merge on or off the highway. Third, the leftmost lanes are underutilized when they could be filled with people who have a long way to go until their offramp.

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

#565

Post by dietr1ch »

Klaus23 wrote: post #357
dietr1ch wrote: post #261

Earlier quoted context omitted.

> 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 tra…

I remember 2 events where the activation was completely out of place and felt it was endangering rather than protecting me.

- Driving from Tahoe to SF where the limited lane visibility due to the slope and a slight twist made the system think I was going to hit the car I was overtaking (from the 2nd and left-most lane). This really felt dangerous since it activated mid-turn and messed with the car's balance.

- The other event was a roundabout where a car yielding to get in behind plants jump-scared the breaking system. At 10-15 mph or so the unexpected breaking wasn't dangerous though, worst-case scenario you get rear ended at low speeds.

Beyond that, overtakes where you slow down as you return to your lane may trip the system, but those cases are fair even though the following distance they intend is a bit too cautious. I reckon my Mom would be holding the roof with both hands if she was there, but my Dad & siblings unfazed.

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

#566

Post by rramadass »

bluGill wrote: post #478
rramadass wrote: post #416

Earlier quoted context omitted.

Addendum: Drive in India and you will understand mathematical concepts of Chance/Randomness/Probability/Non-determinism/Game Theory/etc. along with philosophical concepts of Fate/Destiny/Providence/etc. in so direct and visceral a manner that you will never forget the lessons. Sissified countries with rules and regulations for driving can never give you such direct knowledge. Game Theory - https://en.wikipedia.org/wi…

India is working to fix that. It is slow going, but things have improved over time, and police are enforcing driving laws (at least in some areas)

Yes, of course.

As an Indian, i was just expressing my frustrations in a jokey manner.

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

#567

Post by apparent »

maybewhenthesun wrote: post #563
apparent wrote: post #555

Earlier quoted context omitted.

My decades-long impeccable driving record tends to indicate otherwise. I just don't drive as if I lived in the fantasy land where leaving a long follow distance means I have a lot of room in front of me. It doesn't. It means I get cut off, and the follow distance ends up being shorter than it would have been had I just been following at the same distance as all the other cars on the road.

It is possible of course that the highways you drive are just too busy and the max speed is actually set too high for how busy the road is. That happens more than you'd want because lowering the max of a highway is always an unpopular thing to, even if it's needed. Still, I tend to find that people underestimate the danger of short distances. Often it's just better to accept a 100 cars going in front of you than to s…

This assumes that you can actually maintain a 3 second follow distance. On some roads, you simply cannot, and an attempt to maintain such a distance leads to increased danger from all the cars that cut in.

Simply put: follow distance is not a unilateral decision.

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

#568

Post by ninalanyon »

apparent wrote: post #556
ninalanyon wrote: post #456

Earlier quoted context omitted.

> puts you (and the cars behind you) in a less-safe situation than if you followed more closely. Really? All you have to do is lift your right foot very gently until you have the expected spacing again, no need to sudden changes of speed and if you have traffic aware cruise control it will be done for you. My old Tesla S does it pretty well. I keep it set to three second spacing and when someone cuts in front my car…

Yeah totally works like that, until you get cut off 10 seconds later by another car. If this doesn't happen to you, then you're probably driving like I do, and not leaving 3 seconds of follow distance like they teach in driver's ed.

I do keep three seconds separation most of the time. If possible I engage traffic aware cruise control set to maximum separation for just that purpose. People do cut in but not often; what would be the point of cutting in between two vehicles that are both going slower than your desired speed?

Also perhaps I should have made it clear that I am in Europe where one is expected and required to drive in the outermost (rightmost except in UK and Ireland) lane unless overtaking so the only time anyone would 'cut in' between my car and the one in front is when they are entering a motorway.

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

#569

Post by cloudfudge »

kelnos wrote: post #350
cloudfudge wrote: post #217

Earlier quoted context omitted.

Also, it really doesn't happen that often. I'm that guy following at 3 or 4 car lengths in rush hour traffic and people aren't constantly funneling in front of me. It's a hypothetical "problem" that is bigger in your head than in reality. Sometimes I think it's just people's reflexive scarcity mindset that tells them "that spot must not be that desirable or someone would be in it." Regarding the broader topic of hitt…

I'm that guy following at 3 or 4 car lengths in heavy traffic an people are constantly funneling in front of me, all to go exactly the same speed they'd be going if they were behind me.

It's arguable that their average speed must be ever so slightly higher than yours if they passed you. ;)

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

#570

Post by bcrl »

Many of the merge lanes in California are insanely short compared to those in the rest of the world. The worst are the ones that have merge immediately before an overpass and exit immediately after where merging and exiting have about the width of the overpass to change lanes. I found those infuriating when I used to visit friends in the Bay area. The pattern where I live is the opposite (long exit lane before the overpass and a long merge lane after) and provides far better margins of safety.
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