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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

#111

Post by jeffbee »

drewda wrote: post #3

What is the actual use of this? This research team used Google's first-party location data to identify San Jose's Interstate 880/US 101 interchange as a site with statistically extreme amounts of hard braking by Android Auto users. But you don't need machine learning to know that... San Jose Mercury News readers voted that exact location as the worst interchange in the entire Bay Area in a 2018 reader poll [1] It's n…

Absolutely nothing in this research suggests machine learning. All this is saying is that the hard braking events are associated with dangerous road segments that are well-known by other measures (in this case, reported crash rates).

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

#112

Post by ip26 »

sigseg1v wrote: post #26
avidiax wrote: post #9

Earlier quoted context omitted.

Some amount of that is inevitable, but there is another level of defensive driving where you anticipate poor behavior and arrange that it won't cause an accident. Have a look at a few dash cam accident videos [1]. There are many maladaptive patterns of behavior, but a frequent one that the average good driver can improve on is limiting speed on two occasions: when approaching a blind spot, and when passing stopped or…

Adding on to this, a common reaction I see to online videos of driving incidents is "why did this person just stop? of course you are going to crash into them. They shouldn't have stopped" and many people agreeing with it. It seems they are blind to the fact that if the following driver was using a safe following distance and speed, they should easily be able to stop, making the incident the fault of the driver follo…

Some degree of road safety depends on predictable behavior. I haven’t seen those videos, but suddenly executing a panic stop on the freeway for no good reason at all increases everyone’s risk, even if the car behind you is following at a safe distance. Obviously the following driver bears the most responsibility, but erratic drivers shouldn’t be held to be morally blameless.

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

#113

Post by rootusrootus »

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…

An issue of volume, I would guess. If my quickly gathered stats are accurate, there are on the order of 100K commercial flights every day, and 1B drives. So road accidents are expected to be more numerous, and they usually have less impact than an airliner going down. Also - the NTSB does indeed investigate car accidents on occasion, and when they do, they definitely include systemic analysis.

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

#114

Post by ip26 »

radlad wrote: post #101
presidentender wrote: post #20

I got one of those dongles from my insurance company that plugged into the ODB2 port and reported my driving habits. I was a bad driver. It would frequently beep at me to let me know that I had braked too hard. I was mystified. "What should I have done differently," I'd think, as I raged at the objective machine that judged me so. The next time my brother came to visit, he called mom. "Oh, and presidentender is a goo…

On the other hand, at age 20, with very high premiums, I got one of these devices which never beeped except on a few too-short exit ramps on highways in my city. The choice on these exits is to slow down traffic on the highway, or endure a "hard stop" by braking immediately when you are on the ramp, and coming to a full stop at the stop sign. Just a few of these was enough that my "discount" was only a few dollars. I…

I had a somewhat similar experience - as I recall, most beeps happened as a result of a few stop lights with too-short yellows (e.g. the light changes yellow and you, even though you are below the speed limit, either panic stop or run the red light)

The only possible fix as a driver was to try to develop an intuition for spotting “stale” greens and start slowing down despite the green, anticipating the yellow.

I feel at least partially vindicated by the fact the lights in question eventually had their yellows extended.

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

#115

Post by kube-system »

mountain_peak wrote: post #46
presidentender wrote: post #20

I got one of those dongles from my insurance company that plugged into the ODB2 port and reported my driving habits. I was a bad driver. It would frequently beep at me to let me know that I had braked too hard. I was mystified. "What should I have done differently," I'd think, as I raged at the objective machine that judged me so. The next time my brother came to visit, he called mom. "Oh, and presidentender is a goo…

Maintaining a safe following distance is incredibly challenging on busy freeways where hard braking is often 'required'. Most people have likely found themselves in this situation: vehicle changes lanes in front of you; you slow down to maintain a safe following distance, another car sees a gap and changes lanes in front of you. Repeat for your entire commute. Incredibly frustrating, and I've driven all over North Am…

If you think people are going to cut in front of you, provide a safety cushion large enough to account for that. Aggressive drivers almost universally will consume the forward part of the space cushion you leave. At most you will simply need to lift the accelerator to maintain space. The only time someone cutting in front of you should require hard braking is if they also brake hard.

It does require patience to do this, because all aggressive drivers will use the space you provide. But ultimately the travel time difference in flowing traffic is negligible.

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

#116

Post by dietr1ch »

daringrain32781 wrote: post #98
presidentender wrote: post #20

I got one of those dongles from my insurance company that plugged into the ODB2 port and reported my driving habits. I was a bad driver. It would frequently beep at me to let me know that I had braked too hard. I was mystified. "What should I have done differently," I'd think, as I raged at the objective machine that judged me so. The next time my brother came to visit, he called mom. "Oh, and presidentender is a goo…

I was recently driving a friend and hit a mile-long backup at a freeway exit. At some point in the lineup, a car abruptly cut in front of me to merge into the line. The friend asked "why'd you let them in" - but I didn't let them in on purpose, I was just maintaining a reasonable following distance which people seem to interpret as "hey cut in here for free"

The balance between safe following distance and letting people cut in varies a lot by city. Maybe he learnt to drive elsewhere?

I remember being too aggressive when I got to the Bay Area, and learning how nice it was to be let into the lane I needed to avoid being forced on a 5mi U-turn. When visiting back home I was too nice and people told me so.

I've reached a balance. Aggressive enough not to be taken advantage of, but being nice to drivers in need, specially when it doesn't really change things for me, like when letting a driver in costs me nothing because of how bad traffic is.

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

#117

Post by marcosdumay »

radlad wrote: post #101
presidentender wrote: post #20

I got one of those dongles from my insurance company that plugged into the ODB2 port and reported my driving habits. I was a bad driver. It would frequently beep at me to let me know that I had braked too hard. I was mystified. "What should I have done differently," I'd think, as I raged at the objective machine that judged me so. The next time my brother came to visit, he called mom. "Oh, and presidentender is a goo…

On the other hand, at age 20, with very high premiums, I got one of these devices which never beeped except on a few too-short exit ramps on highways in my city. The choice on these exits is to slow down traffic on the highway, or endure a "hard stop" by braking immediately when you are on the ramp, and coming to a full stop at the stop sign. Just a few of these was enough that my "discount" was only a few dollars. I…

If there's no extra exit lane, the right choice is to slow down traffic on the highway.

What will happen if there's some oil spill or brake failure at the point you think you should break hard?

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

#118

Post by matsemann »

dghlsakjg wrote: post #93
WarmWash wrote: post #29

Earlier quoted context omitted.

If you take a seasoned motorcycle rider and put them in one of those dashcam subs, they'll rip their hair out. Most people have near zero defensive driving skill, and view someone pulling out in front of them as "nothing I could have done", when the dashcam shows the offending driver showed 5 signs of pulling out ages before the accident occurred.

Cyclists too. I do both and I am constantly surprised at the lack of situational awareness of drivers when I’m a passenger in their cars. I think truckers probably get the same thing too.

Same, I cycle everywhere and almost feels like I've developed a sixth sense for when a driver will do something stupid.

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

#119

Post by avidiax »

grog454 wrote: post #77
ominous_prime wrote: post #38

Earlier quoted context omitted.

It certainly makes sense as a proxy for competence across a diverse population for insurance purposes. You have a baseline of hard braking events that a competent driver may encounter under normal circumstances. If a driver routinely exceeds that number, they are either unable to correctly estimate closing distance and reaction times, which makes them higher risk for causing accidents, or they are driving abnormally…

> You said it correctly with "would've been safer to start building a distance buffer", that is the proxy the insurance companies want to use for risk assessment. Then use it? Mandate reaction speed tests or other driving mechanics competency evaluation (not road sign comprehension) and watch insurance margins explode. The driver in my example did poorly and scored top marks in the heuristic.

I assume you are referring to this video: https://www.youtube.com/watch?v=sEpHyMtDcPY

> building a distance buffer", that is the proxy the insurance companies want to use for risk assessment.

The cam car did not need to have a hard braking event (HBE) to start building distance.

Even if they did, the insurance companies are looking for a pattern of HBEs to assess risk. I agree that there is a theoretical high-risk driver that never has a HBE because they always try to maneuver instead of breaking. There are other heuristics for this (high lateral acceleration, high jerk). And the ultimate heuristic: failing to avoid accidents, thus having a claim history.

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

#120

Post by Gud »

presidentender wrote: post #20

I got one of those dongles from my insurance company that plugged into the ODB2 port and reported my driving habits. I was a bad driver. It would frequently beep at me to let me know that I had braked too hard. I was mystified. "What should I have done differently," I'd think, as I raged at the objective machine that judged me so. The next time my brother came to visit, he called mom. "Oh, and presidentender is a goo…

I can only speak for Europe, but driving too closely to the driver in front is unfortunately how 90% of drivers drive.

Unless it’s in Netherlands, where it’s 100%.

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