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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

#61

Post by infecto »

zahlman wrote: post #13
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…

> 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 braking event is an effective mechanism for behavior change (other companies have similar tech) ... How do people not notice that they are braking hard?

Because their definition of hard is not a slam on the pedal braking. It’s definitely out of the normal stopping but it’s not as hard as you might imagine. I could easily see people not realizing this.

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

#63

Post by amanaplanacanal »

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…

Caltrans could lower the speed at that interchange, and use traffic calming to actually get people to drive slower. Good traffic engineering can still make a difference even with the existing physical limitations.

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

#64

Post by infecto »

amanaplanacanal wrote: post #58
infecto wrote: post #12

Earlier quoted context omitted.

I hate the warning myself and I use the app the parent is from. I also suspect I am an outlier in not having an accident in 20 years. It’s this obnoxious audio warning that tells me I had a hard breaking and it’s 9/10 because I stopped at a red light that I would not have made on yellow. And then it sends me tips and reminders about reducing hard breaking events and it’s annoying. I know they have done the analysis b…

The lights should be timed so that you don't have to do that if you are driving the posted speed, but I know that's not always true.

No doubt but I think it’s two fold. Lights stink in that so many are setup not for safety so they rip through the yellow quick as possible. Second, I don’t think of these as hard breaking even but I am sure from a data perspective the cutoff is probably correct. Hard invokes a vision of an emergency brake event. These apps really capture any medium to hard brake event.

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

#65

Post by yial »

ARandomerDude wrote: post #47
HoldOnAMinute wrote: post #35

Earlier quoted context omitted.

Is there any vehicle that uses it's sensors to make a gentle suggestion about following distance? It's probably the best single thing anyone can do to improve safety. It also reduces wear-and-tear on your car, and increases your fuel economy as a side benefit. Why hasn't gamification of safe driving habits been built directly into the car itself before now?

> Why hasn't gamification of safe driving habits been built directly into the car itself before now? I am so glad it hasn't. Data point of one, but gamification now has the opposite effect on me: it's such a well-worn pattern that it just annoys me. It was great when it was novel. I wonder how many others feel the same but without sampling it's hard to know.

I concur with you regarding gamification. When I am aware of the gamification it fills me with exhaustion to annoyance to extreme frustration. This is especially true of things that I want to use for one purpose.

I also think some of the car sensors (Subaru especially) that are trying to make you safer are notoriously bad.

I also find the random “coffee break” notice on Subarus frustrating.

My personal examples: “eyes on the road” - triggered frequently by one pair of sunglasses I have, looking left to check blind spot, checking mirrors, etc.

“Hands on the steering wheel” - triggered occasionally on long drives when I have been giving input, but very light input.

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

#66

Post by yial »

jjice wrote: post #42
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 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.

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

#67

Post by hiq »

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…

As a passenger, I really notice the difference, and I wish more drivers (including professionals) would learn as you did. It probably saves energy as well, especially when driving in cities, although I guess it's marginal.

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

#68

Post by geocrasher »

avidiax wrote: post #9
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.

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…

I learned next-level defensive driving by bicycle commuting to work 5.5 miles each way on busy roads in rush hour traffic. On a bicycle you're invisible, and if you expect any less, you're going to get hurt. As it was, I had some very very close calls- at least one of them had the potential to be fatal. Ironically, the only time I ever crashed was my own fault.

But now even when in a car, I retain that "I'm invisible" mentality, which makes me much more aware of what other drivers are doing, and much more skeptical of their ability to make good decisions. This has saved me several times.

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

#69

Post by badc0ffee »

yial wrote: post #60
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 doesn’t - but people don’t necessarily make rational choices regarding speed and driving. There’s a tendency to de personalize other drivers. A slight increase in average speed really only makes a significant difference over long drives. (5 mph increase over a 10 hour drive can cut off 50 minutes). Otherwise we are talking about small differences in efficiency. (I would be very open to another opinion here.). My o…

> (5 mph increase over a 10 hour drive can cut off 50 minutes)

You can't really say that without knowing the starting speed, or alternatively the distance. All you can say is that a 5 mph increase over a 10 hour drive with get you 50 miles farther.

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

#70

Post by yial »

Sharlin wrote: post #36
advisedwang wrote: post #14

Earlier quoted context omitted.

Insurance is thinking about hard braking as an indicator of a driver with riskier behaviour. Google is showing that it can also be an indicator of risky road designs. These actually kind of point in opposite directions in terms of the causes of hard braking. The certainly can be used in different ways.

Some road designs are risky because they encourage risky behavior. And "risky" is relative. A good driver should recognize risky road segments and drive even more defensively than normally.

This is true - but it’s hard even for “good” drivers to always understand especially on roads they might not be familiar with.

Example: open space on either side of the road, tends to encourage people to drive faster.

Closing that space (whether by buildings, shrubbery, etc ) will slow the speed.

But I will say there are also “obvious” bad designs - the rare far to short on ramp to merge, where drivers don’t understand how to adjust.

Or the one I most frequently encounter are “blind spots” created by the speed of an intersecting road, where a mirror may be attached to a pole / tree, or a sign reminding people to look left right left, or even instructing where cars should be beyond for a safe pull out.

I know of one intersection near me that both has markers on the road(don’t pull out if cars are at or beyond this marker), and a reminder about looking, but still has a high frequency of accidents.

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