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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

#91

Post by rootusrootus »

ChuckMcM wrote: post #78
mountain_peak wrote: post #46

Earlier quoted context omitted.

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…

Okay I'm thinking of a very Shenzen kind of gizmo for your car that projects a bright red laser "keep out" box on the road in front of your car which is adjusted in size for your current speed.

I think a lot of people would just consider that a challenge.

On the occasion when I am towing our travel trailer, it is really incredible how unsafe that makes other drivers act around me. They will jam themselves in front of me at all costs, with no consideration for physics.

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

#92

Post by kube-system »

bluGill wrote: post #23
kube-system wrote: post #6

Earlier quoted context omitted.

> Simply letting people know that they had a hard braking event is an effective mechanism for behavior change Has this been studied in isolation? Many of the tools that notify upon hard braking also are used to impose financial penalties for doing so... I suspect people may be reacting to the financial incentives.

Does it matter why? The important part is getting people to change behavior. of course if they change such that they don't break hard when needed that is bad, but if the change such that they don't need to break hard in the first place because they slow down in places that are dangerious that is the point.

> Does it matter why? The important part is getting people to change behavior.

Yeah, if you want to do that, it would be helpful to know whether a financial incentive is required for the effect or not.

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

#93

Post by dghlsakjg »

WarmWash wrote: post #29
pavel_lishin wrote: post #4

Earlier quoted context omitted.

My mom had a device installed in her car to get a discount on her insurance, and she was always upset at the hard braking thing - whenever she did it, it was because another car was doing something unsafe that she couldn't control, like pulling out in front of her.

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.

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

#94

Post by Noumenon72 »

mountain_peak wrote: post #55
amanaplanacanal wrote: post #50

Earlier quoted context omitted.

Does it really matter though? Is the end result just a couple of minutes later in a 30 minute commute? Or does it actually make a large difference in travel time?

It used to be more of an issue when I was younger. Now that I'm older and more 'seasoned' (plus reflexes do slow down), I'm far more patient and have no issue maintaining a healthy following distance. I think the statistics reflect this in age vs. accident rate as well. Unfortunately, sometimes over a 45 minute freeway commute, dropping back repeatedly means arriving 15 minutes or more later. Again, no big deal now,…

For your commute to take 4/3 the time, you would have to be averaging 3/4 the speed -- going 45 in a 60. That doesn't make sense because even going 55 would mean traffic pulled away from you rather than you having to drop back from it. Going 55/60ths the speed means you arrive in 60/55ths the time, or an extra 4 minutes on a 45 minute commute.

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

#95

Post by sagarm »

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 highway driving requires hard braking, you're a bad driver.

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

#96

Post by dghlsakjg »

kube-system wrote: post #6
harshaw wrote: post #2

Nice research. This is fairly well known in insurance circles. Most auto insurers that do telematics consider hard braking the strongest indicator of risk. One of the things that we do at work (Cambridge Mobile Telematics) is build tools to deal with this risk. We have apps that monitor driving and we play a tone to indicate that a hard braking event was detected. Simply letting people know that they had a hard braki…

> Simply letting people know that they had a hard braking event is an effective mechanism for behavior change Has this been studied in isolation? Many of the tools that notify upon hard braking also are used to impose financial penalties for doing so... I suspect people may be reacting to the financial incentives.

Anecdotally: I leave the fuel efficiency display as the instrument cluster display on the hybrid that I drive and it significantly changes both my acceleration and braking behavior.

There is a minor financial aspect (price of fuel), but I’m far more interested in seeing if I can get a better “green score” at the end of the drive.

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

#97

Post by yial »

Noumenon72 wrote: post #88
yial wrote: post #51

Earlier quoted context omitted.

This is accurate in many ways. I use the auto cruise feature on my car frequently and I notice several things happen unless I set the distance as close as possible (which I don’t like to do. ). 1. In any amount of traffic above “a few cars” people will cut in front of me, sometimes two, negating the safe following distance. Regardless of speed. 2. If I have a safe following distance while waiting for someone to get o…

I always wonder why so many people observe this when I never have. It makes no sense logically; it's the speed of the car in front of you that determines whether they should switch lanes, not the size of the gap behind it. There is no reason for them to cut in when your lane is no faster. Perhaps you are just the sole person leaving enough room for people to execute needed lane changes. At any rate, even if people ar…

In the auto cruise example, it’s leaving perhaps 2 - 2.5 car distances. In close traffic the average human I would bet is leaving 1 or less then 1.

The issue is not that I can’t rebuild the following distance, the point I’m trying to make is that even if I constantly rebuild the following distance it sets off a cascading effect.

I’m following at set speed, car cuts in front, hits brakes, I now slow down, car behind me slows down, I rebuild following distance and car perhaps 7-8-9 cars behind me repeats because at some point the cascade magnifies to a larger slowdown behind.

Can I mitigate this by manually letting my distance be closer for a time, and slowly easing to larger ? Yes.

But if I allow the car to do it automatically, it will increase the follow distance at a rate that causes a cascade in tight traffic.

Though - I do think with these discussions on HN- it does depend on where you’re driving.

My experiences are centered on East Coast, thinking of route 80, 81, 83, etc. or Philly / New York City.

The driving experience is radically different in California, Florida , or the mid west.

I would say when driving in California people seem to navigate traffic better. (SF, LA) then on drivers on 80/81/83. (Or perhaps it’s due to better designed roads ).

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

#98

Post by daringrain32781 »

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"

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

#99

Post by dghlsakjg »

munificent wrote: post #31
harshaw wrote: post #2

Nice research. This is fairly well known in insurance circles. Most auto insurers that do telematics consider hard braking the strongest indicator of risk. One of the things that we do at work (Cambridge Mobile Telematics) is build tools to deal with this risk. We have apps that monitor driving and we play a tone to indicate that a hard braking event was detected. Simply letting people know that they had a hard braki…

How does one not already know that they had a hard braking event? Surely the jamming their foot on the brake pedal and the rapid deceleration would send an even more obvious signal than playing a chime?

A lot of people don’t realize that what they consider normal driving is actually aggressive driving by other metrics

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

#100

Post by yial »

vardalab wrote: post #82
yial wrote: post #51

Earlier quoted context omitted.

This is accurate in many ways. I use the auto cruise feature on my car frequently and I notice several things happen unless I set the distance as close as possible (which I don’t like to do. ). 1. In any amount of traffic above “a few cars” people will cut in front of me, sometimes two, negating the safe following distance. Regardless of speed. 2. If I have a safe following distance while waiting for someone to get o…

I don't know you can find that traffic always bunches up. And if one is content to sit in the gaps in between, almost never anybody cuts in. I drove twice 1000 mile trips each way last year and it kind of worked. It's more of a mindset than anything else. Fastlane is not that fast or it would be empty, lol.

The fast lane isn’t always faster is very true! Haha

What I will say is some of this may be the difference between manual driving - and automatic.

If I’m manually driving - where my follow distance fluctuates more due to speed / traffic - almost no one cuts in.

If I am driving where I’m using the vehicle to maintain a perfect set distance, people cut in.

Again, anecdotal

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