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 braking event is an effective mechanism for behavior change (other companies have similar tech)
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 not a lack of knowledge by Caltrans or Santa Clara County's congestion management agency that is keeping that interchange as-is. Rather, it's the physical constraints of a nearby airport (so no room for flyovers), a nearby river (so probably no tunneling), and surrounding private landowners and train tracks.
Leaving aside the specifics of the 880/101 interchange, the Google blog post suggests that they'll use this worst-case scenario on a limited access freeway to inform their future machine-learning analyses of other roads around the country, including ones where presumably there are also pedestrians and cyclists.
No doubt some state departments of transportation will line up to buy these new "insights" from Google (forgetting that they actually already buy similar products from TomTom, Inrix, StreetLight, et al.) [2]
While I genuinely see the value in data-informed decision making for transportation and urban planning, it's not a lack of data that's causing problems at this particular freeway intersection. This blog post is an underbaked advertisement.
"Our analysis of road segments in California and Virginia revealed that the number of segments with observed HBEs was 18 times greater than those with reported crashes. While crash data is notoriously sparse — requiring years to observe a single event on some local roads — HBEs provide a continuous stream of data, effectively filling the gaps in the safety map."
So we don't have to wait until an accident actually occurs before we can identify unsafe roads and improve them.
Not surprising but it is nice to have these data streams to explore locations that could potentially be remediated. I think anyone who drives interstates in metro areas would agree cloverleaf interchange are generally terrible with any significant traffic. Add in the general proclivity to drive much higher than the posted speed limit and these become dangerous due to the speed differentials and we've known this for 50 years.
"A 1974 study by Hall and Dickinson showed that speed differences contributed to crashes, primarily rear end and lane change collisions"
Hall, J. W. and L. V. Dickinson. An Operational Evaluation of Truck Speeds on Interstate Highways, Department of Civil Engineering, University of Maryland, February, 1974.
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 good driver now." I didn't put the pieces together right away, but it turned out that the dongle had actually trained me, like a dog's shock collar.
The reason for my too-frequent hard-braking events wasn't speed, although that would be a contributing factor. It was a lack of appropriate following distance. Because I'd follow the drivers in front of me too closely I'd have to brake hard if they did... Or if they drive normally and happened to have a turn coming up.
Over the period I had the insurance spy box in my truck I learned without thinking about it to increase my following distance, which meant that riding with me as a passenger was more comfortable and it beeped less often. Of course since I'd been so naughty early during the evaluation they didn't decrease my rates, but I think the training probably did make me statistically less likely to crash.
While i find everything about this post thoroughly dystopian; I will state that I don't break harshly, just about ever, my car still has it's original breakpads (they still have some life, about a cm and a half to two) and it had 107k on the odo. Never been in an accident outside of getting break-checked by an insurance scammer when I was 19, and a head on when i was stopped at a stop sign.
Although I keep a varying follow distance, if there is an open lane immediately adjacent to me, I don't care if i'm tailing someone a bit, but if I'm boxed then you better believe it's 6+ car distance.
Kudos on you for acknowledging that your behavior changed! It is depressing how many people online are convinced that the emergency braking systems are too aggressive. The best is the cohort that insist these systems will be what causes accidents.
It would be really interesting if cars did this by default. Maybe it could figure out your threshold, how much of an outlier you are, and then you could opt-in to a new threshold that's somewhat better and/or closer to average.
I have this image in my mind of a discussion taking place in a high speed rail possibly around 2100 where people will look back and say: "I cannot believe we had people driving 2ton steel boxes back in the day, I cannot even compute those micromorts"
>I'd follow the drivers in front of me too closely
Best trick for managing this is to "drive through" the car in front of you. That is, judge your following distance based not on the car in front of you, but on the car in front of THEM.
And you don't have to "drive through" all the way down the road - it only takes one car/one level of abstraction for this approach to yield really great benefits, try it if you don't believe me.
Inter-car distance is always a safety factor but can immensely reduce lane throughput. There is a compromise. I remember a few decades ago, in California at least, they suggested the drivers keep a one-car length distance from the leading car for every 10m/h speed. Funny that I had to convert it in km/h.
I've long thought that drivers should have some kind of black box monitoring their driving habits/abilities with that kind of acceleration sensing. As well as feeding into insurance databases to give safer drivers lower premiums, I think it would be ideal to highlight when older drivers start to lose their faculties. Another big benefit could be to diagnose some diseases early on - if a driver suddenly becomes less smooth, there's a good chance that they have some new eye or brain condition.
Driving predictably and smoothly is good. The only time there should be any braking considered remotely "hard" would be when something surprised you, which should almost never happen.
I've got a tracker and it keeps showing "sharp turn" right in my neighborhood. It's counting the turn in to my driveway - a 90 degree turn - as a "sharp turn". It doesn't seem to matter how slow I go - I'm not racing in to the driveway - generally slowed to walking speed by that point - and I'm still getting 'dinged' every day for this.
I knew an actuary, and remember wondering "why do sports cars cost so much to insure?" Turns out that actuaries have very good data about which kinds of cars have more accidents, and cost more to insure.
She said the only time that the data and the rates do not match is after an accident. After an accident, the rates go up, however drivers are more careful and are statistically less likely to have an accident.
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 something black and white. Easy to digest. We'll then keep doing it over and over again because we never changed the circumstances.
The second approach is holistic, for example even if the pilot made a mistake, why did they make a mistake, and what can we do to prevent that mistake (e.g. training, culture, etc)? But maybe other elements also played a part like mechanical, software, airport lightning, communications, etc.
I bet everyone reading this knows of a road near them that is an accident hotspot and I bet they can explain WHY it is. I certainly do/can, and I see cops with crashed cars there on a weekly basis. Zero changes have been made to the conditions.
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.
There’s a section of I-15 in Utah’s Salt Lake County which reliably has a crash on weekdays at 6pm. It was unfortunately at a pinch point in the mountains with no good alternate route… very annoying.
In a similar way that Google Maps shows eco routes, it’d be fun for them to show “safest” routes which avoid areas with common crashes. (Not always possible, but valuable knowledge when it is.)
When we worked at a p2p car sharing company it was well understood what a treasure trove that past accelerometer data was as good input to frequency prediction of a claim resulting from a particular rental.
Aim to make the road laminar. Every time you hard brake, you're causing the milk jug to glug, making a ripple of entropy as momentum turns to heat from your brakes and those behind you, sometimes in perpetuity. I learned this while doing a 1.5hr daily commute in a Subaru with a clapped out manual transmission. I wanted to conserve energy shifting, but realized I was now participating in large choreographed dance of "smooth" with other drivers who already knew this. There are many of us. And we all glare at the driver blinking their red lights on the interstate indicating that they're loud and proud of introducing turbulence to an otherwise peaceful system.
I try to do the same, and do my part to smooth out the wrinkles in traffic.
What I would really like in a car is not only my current speed, but the relative speed to the car ahead of me. Given my car has cameras and other sensors for cruise control and other features this ought to already be possible.
This is the natural response of tapping the brakes for any slowdown: people naturally over compensating and chain reactions happening behind them. This video shows how stop and go traffic forms and snowballs with no real impetus beyond mis estimated follow distance.
What this video also shows is that if people pull off more or less at the same time and speed of the car in front then this is a complete non issue. Unfortunately most people are unable to watch a few cars ahead and be ready to pull of when the car in front does, and so we have this situation where each car takes around 5-10 seconds to pull away. multiply this by hundreds or thousands of cars and you end up with a phantom traffic jam.
I always pull away at the same speed as the car in front of me and maintain the same distance as when we were stopped. It is very easy to do and completely eliminates traffic build up if multiple people do it at the same time.
This is the same reason that we have amber lights on traffic lights, so that the drivers have time to get into gear and start pulling away so that when the light goes green they are imediately travelling through it, causing no excess traffic build up at the lights. Again unfortunately people dont concentrate when they are stopped at lights and so you have the situation where they see the light go green and then proceed to start changing into gear and remove the handbrake. By the time they are moving through the green light, they have already taken 10-20 seconds of green light time, eating well into the time alotted for cars to be travelling across the junction.
The only thing which will solve this is driverless cars, meaning that the cars can all talk to each other and move at the same time like a chain. I welcome this advancement to elimante human error in driving and get rid of traffic jams for good.
THIS this so much. Look far out ahead and if you see traffic compressing then slow down sooner so as to try to make that compression vanish for those behind you.
Of course braking/change in velocity creates waves. But this effect is overemphasized in my opinion. Locally analyzed, traffic can be simplified incredibly by observing that a lane's maximum throughput is simply given by following spacing, measured in time.
If drivers are using a 2 second following distance, commonly taught in driving school, then max throughput is simply
1 car / 2 sec
If you double following distance, you halve the throughput. If you halve following distance, you double your throughput. The throughput of a (full, i.e. rush-hour) road has nothing to do with speeds of people driving, and everything to do with following distance.
IMO there is nothing worse than drivers on highways who think that by leaving bigger gaps and slowing less rapidly they are 'smoothing' out the traffic and helping the whole road run better. You are not, you are just making the whole road run slower and taking up more space for yourself on a crowded road.
This is untrue, there have been studies done that discovered the primary cause of traffic is following too close. Following further away really does reduce the amount of traffic. It seems unintuitive, but consider: every time you brake, the person behind you has to brake a teensy bit longer. And then the person behind them, and behind them. That little bit of extra time accumulated quickly and grinds the highway to a halt.
I'd love to have a danger heat map displayed on a HUD while driving. Say a default green banner that goes red near a hot spot or even animates near a current hazard. Mostly it could use these same stats, but then be strident if anything unpredictable is detected nearby.
As I mentioned in another comment, Waze does this. There's a stretch of the Capital Beltway that, if it was on a race track and compressed, would be called "esses." It's totally fine to navigate at 80 MPH with no drama in any mechanically sound, post-1980 car, but it catches mediocre drivers by surprise. Waze throws up a "history of accidents" message whenever I drive through it.
I'm really curious what their data looks like at the various racetracks and circuits. Fun fact; most raceways have accurate street-level indicators (including that they are one-way, but sadly they are not the best racing line) on most online maps, and my car did complain to me in its weekly report about a lot of hard turns, quick acceleration, and hard braking with helpful pins on e.g. Laguna Seca or Thunderhill corners.
In theory, the most dangerous turns would probably have higher variance on hard braking data.
OK, now that you have this data, give me a "prefer safer routes" option in Google Maps navigation!
While you're at it, give me an option to avoid unprotected left turns and to avoid making a left turn across a busy road where cross traffic does not stop. (But only during heavy traffic; it's fine when nobody is on the road.) Not only are these more dangerous, they're also more stressful and they also introduce annoying variation into my travel time.
Hard braking could be detected externally; you can tell when vehicles are braking hard from the deceleration and suspension effects, without any surveillance equipment installed in them.
That's not gonna be something Google would research, of course, due to next to no alignment with their interests.
This is a great use of this technology. In aggregate, these hard braking events _do_ tell us about road design issues. They also tell us about problematic drivers, in aggregate.
I'll never use one of these dongles, though, because I don't want my every move second-guessed. There's nothing _inherently_ dangerous about isolated hard braking or cornering or acceleration events. It all depends on context. Am I braking hard to avoid an obstacle or mistake by another driver? Is there someone behind me that's likely to rear-end me, or am I in the middle of a highway in the desert? Did I just replace my brake pads and I'm bedding in the new pads?
I don't want to have to worry about whether I've used up my invisible quota before the algorithm decides I should be moved into a more expensive insurance bracket.
Too bad there's no map with such indicators, I'd definitely use it for my route planning, especially in unknown area. I usually know pretty well dangerous parts if I drive there frequently.
In unknown roads/highways I can predict hard bumps/gaps by seeing dark oil spots in the middle of each lane.
Wait, what do they teach in North America? Never heard the term "following distance" before now. Sounds misleading.
In Britain at least we call it "braking distance" and you're supposed to leave 2 seconds at least between you and the person in front. Count it off a lamp post/sign etc.
In certain at-risk areas they use chevrons on the road and signs telling you to keep at least 2 chevrons between you and the car in front.
People definitely always get into my braking distance in slower moving traffic, so that happens here too of course. But when things are moving well I likely push the limit and am generally moving faster than most others: going by GPS speed vs speedo, pushing a little into the discretionary and unofficial +10% guidance etc. And weirdly enough I do this for safety and fuel economy.
I generally prefer to avoid other vehicles as much as possible in all situations. But I was a motorbike rider in my youth. Once a defensive driver...
From that perspective, following distance sounds way more like a gap I want to close up than braking distance does.
There are only two conditions under which I have had to hard brake in more than 30 years of driving:
1. I'm on a race track or back road enjoying curves
2. Some asshole did something stupid in front of me.
I agree that hard braking is an accurate metric for road segment crash risk, but what I find upsetting is that insurance companies that use vehicle data treat /all/ hard braking equally. In reality, the risk is caused not by every person who hard brakes, but by the first person in a line of cars that hard brakes.
More on #2 above is that my observation has been MOST of the time, the braking was COMPLETELY unnecessary. Often the person hard braking that starts the chain has absolutely nothing in front of them to the horizon and is probably on their phone watching TikTok, suddenly looked up and realized they were driving and braked as a spooking reaction. This happens, observably, so often that there are active conspiracies on the Internet that the government hires people to drive like assholes to cause traffic. Obviously that's complete bunk, but my observation here is certainly not unique.
Rather than spying on everyone using our vehicle data to charge us ever more money (I've had zero at-fault accidents in nearly 30 years of driving, but my rates only go up), maybe we should enforce attentiveness on the road and start punishing those who are left-lane hogs (causing many lane changes, which are also risky), on their phone, or drunk. It's really obscene these days driving on American roads, it seems like everyone drives markedly worse since the pandemic /and/ enforcement has gone to nothing. The only time I see people get pulled over now is in speedtrap small towns.
I considered writing an app you would take on a car ride that would record accelerometer readings indicative of a pothole. Geotag the reading and push is anonymously to a server.
Enough events should show clusters where potholes likely exist. You would think cities would love that kind of data.
This may sound a little cynical but cities often don't like having an inventory of infrastructure problems because it creates an obligation to address it or pay for tire/rim damage if there was prior written notice of a problem. I saw this happen with sidewalk condition data as another example.
How happy would HN be if, instead of buying location data as an end run around the 4th amendment, states and municipalities bought traffic data and used it to make safer streets and highways?
Table 1 and Figure 4: why are the Virginia controlled-access highways different? That population stands out in a way that smells like either a cultural difference or a policy difference.
I spend most of my time in California, have lived in SoCal and NorCal, and I spend a fair chunk of time driving around Virginia. My guess is that there's something fishy with the Virginia data being reported. Because if there is anyplace on earth with an insane number of controlled access roads, it's gotta be NVA/DC metro area (or the Tri-Border Area as I like to call it).
Also, they need to either update the caption for Figure 4, or move the plots to correspond with the caption. Clearly the Virginia data is on top (or the code is wrong, which seems exceedingly unlikely).
63 comments
[ 3.5 ms ] story [ 65.9 ms ] threadThis 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 not a lack of knowledge by Caltrans or Santa Clara County's congestion management agency that is keeping that interchange as-is. Rather, it's the physical constraints of a nearby airport (so no room for flyovers), a nearby river (so probably no tunneling), and surrounding private landowners and train tracks.
Leaving aside the specifics of the 880/101 interchange, the Google blog post suggests that they'll use this worst-case scenario on a limited access freeway to inform their future machine-learning analyses of other roads around the country, including ones where presumably there are also pedestrians and cyclists.
No doubt some state departments of transportation will line up to buy these new "insights" from Google (forgetting that they actually already buy similar products from TomTom, Inrix, StreetLight, et al.) [2]
While I genuinely see the value in data-informed decision making for transportation and urban planning, it's not a lack of data that's causing problems at this particular freeway intersection. This blog post is an underbaked advertisement.
[1] https://www.mercurynews.com/2018/04/13/101-880-ranks-as-bay-...
[2] https://www.tomtom.com/products/traffic-stats/ https://inrix.com/products/ai-traffic/ https://www.streetlightdata.com/traffic-planning/
From the article:
"Our analysis of road segments in California and Virginia revealed that the number of segments with observed HBEs was 18 times greater than those with reported crashes. While crash data is notoriously sparse — requiring years to observe a single event on some local roads — HBEs provide a continuous stream of data, effectively filling the gaps in the safety map."
So we don't have to wait until an accident actually occurs before we can identify unsafe roads and improve them.
"A 1974 study by Hall and Dickinson showed that speed differences contributed to crashes, primarily rear end and lane change collisions"
Hall, J. W. and L. V. Dickinson. An Operational Evaluation of Truck Speeds on Interstate Highways, Department of Civil Engineering, University of Maryland, February, 1974.
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 good driver now." I didn't put the pieces together right away, but it turned out that the dongle had actually trained me, like a dog's shock collar.
The reason for my too-frequent hard-braking events wasn't speed, although that would be a contributing factor. It was a lack of appropriate following distance. Because I'd follow the drivers in front of me too closely I'd have to brake hard if they did... Or if they drive normally and happened to have a turn coming up.
Over the period I had the insurance spy box in my truck I learned without thinking about it to increase my following distance, which meant that riding with me as a passenger was more comfortable and it beeped less often. Of course since I'd been so naughty early during the evaluation they didn't decrease my rates, but I think the training probably did make me statistically less likely to crash.
Although I keep a varying follow distance, if there is an open lane immediately adjacent to me, I don't care if i'm tailing someone a bit, but if I'm boxed then you better believe it's 6+ car distance.
This diagram changed how I think about following distance: https://entropicthoughts.com/keep-a-safe-following-distance
Best trick for managing this is to "drive through" the car in front of you. That is, judge your following distance based not on the car in front of you, but on the car in front of THEM.
And you don't have to "drive through" all the way down the road - it only takes one car/one level of abstraction for this approach to yield really great benefits, try it if you don't believe me.
[0] https://www.npr.org/2018/06/12/619109741/clicker-training-fo...
She said the only time that the data and the rates do not match is after an accident. After an accident, the rates go up, however drivers are more careful and are statistically less likely to have an accident.
- 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 something black and white. Easy to digest. We'll then keep doing it over and over again because we never changed the circumstances.
The second approach is holistic, for example even if the pilot made a mistake, why did they make a mistake, and what can we do to prevent that mistake (e.g. training, culture, etc)? But maybe other elements also played a part like mechanical, software, airport lightning, communications, etc.
I bet everyone reading this knows of a road near them that is an accident hotspot and I bet they can explain WHY it is. I certainly do/can, and I see cops with crashed cars there on a weekly basis. Zero changes have been made to the conditions.
"Crash" not "accident":
* https://crashnotaccident.com
In a similar way that Google Maps shows eco routes, it’d be fun for them to show “safest” routes which avoid areas with common crashes. (Not always possible, but valuable knowledge when it is.)
What I would really like in a car is not only my current speed, but the relative speed to the car ahead of me. Given my car has cameras and other sensors for cruise control and other features this ought to already be possible.
This is the natural response of tapping the brakes for any slowdown: people naturally over compensating and chain reactions happening behind them. This video shows how stop and go traffic forms and snowballs with no real impetus beyond mis estimated follow distance.
I always pull away at the same speed as the car in front of me and maintain the same distance as when we were stopped. It is very easy to do and completely eliminates traffic build up if multiple people do it at the same time.
This is the same reason that we have amber lights on traffic lights, so that the drivers have time to get into gear and start pulling away so that when the light goes green they are imediately travelling through it, causing no excess traffic build up at the lights. Again unfortunately people dont concentrate when they are stopped at lights and so you have the situation where they see the light go green and then proceed to start changing into gear and remove the handbrake. By the time they are moving through the green light, they have already taken 10-20 seconds of green light time, eating well into the time alotted for cars to be travelling across the junction.
The only thing which will solve this is driverless cars, meaning that the cars can all talk to each other and move at the same time like a chain. I welcome this advancement to elimante human error in driving and get rid of traffic jams for good.
If drivers are using a 2 second following distance, commonly taught in driving school, then max throughput is simply
If you double following distance, you halve the throughput. If you halve following distance, you double your throughput. The throughput of a (full, i.e. rush-hour) road has nothing to do with speeds of people driving, and everything to do with following distance.In theory, the most dangerous turns would probably have higher variance on hard braking data.
While you're at it, give me an option to avoid unprotected left turns and to avoid making a left turn across a busy road where cross traffic does not stop. (But only during heavy traffic; it's fine when nobody is on the road.) Not only are these more dangerous, they're also more stressful and they also introduce annoying variation into my travel time.
That's not gonna be something Google would research, of course, due to next to no alignment with their interests.
I'll never use one of these dongles, though, because I don't want my every move second-guessed. There's nothing _inherently_ dangerous about isolated hard braking or cornering or acceleration events. It all depends on context. Am I braking hard to avoid an obstacle or mistake by another driver? Is there someone behind me that's likely to rear-end me, or am I in the middle of a highway in the desert? Did I just replace my brake pads and I'm bedding in the new pads?
I don't want to have to worry about whether I've used up my invisible quota before the algorithm decides I should be moved into a more expensive insurance bracket.
In unknown roads/highways I can predict hard bumps/gaps by seeing dark oil spots in the middle of each lane.
PDF download: https://iase-pub.org/ojs/SERJ/article/download/215/119/726
In Britain at least we call it "braking distance" and you're supposed to leave 2 seconds at least between you and the person in front. Count it off a lamp post/sign etc.
In certain at-risk areas they use chevrons on the road and signs telling you to keep at least 2 chevrons between you and the car in front.
People definitely always get into my braking distance in slower moving traffic, so that happens here too of course. But when things are moving well I likely push the limit and am generally moving faster than most others: going by GPS speed vs speedo, pushing a little into the discretionary and unofficial +10% guidance etc. And weirdly enough I do this for safety and fuel economy.
I generally prefer to avoid other vehicles as much as possible in all situations. But I was a motorbike rider in my youth. Once a defensive driver...
From that perspective, following distance sounds way more like a gap I want to close up than braking distance does.
1. I'm on a race track or back road enjoying curves 2. Some asshole did something stupid in front of me.
I agree that hard braking is an accurate metric for road segment crash risk, but what I find upsetting is that insurance companies that use vehicle data treat /all/ hard braking equally. In reality, the risk is caused not by every person who hard brakes, but by the first person in a line of cars that hard brakes.
More on #2 above is that my observation has been MOST of the time, the braking was COMPLETELY unnecessary. Often the person hard braking that starts the chain has absolutely nothing in front of them to the horizon and is probably on their phone watching TikTok, suddenly looked up and realized they were driving and braked as a spooking reaction. This happens, observably, so often that there are active conspiracies on the Internet that the government hires people to drive like assholes to cause traffic. Obviously that's complete bunk, but my observation here is certainly not unique.
Rather than spying on everyone using our vehicle data to charge us ever more money (I've had zero at-fault accidents in nearly 30 years of driving, but my rates only go up), maybe we should enforce attentiveness on the road and start punishing those who are left-lane hogs (causing many lane changes, which are also risky), on their phone, or drunk. It's really obscene these days driving on American roads, it seems like everyone drives markedly worse since the pandemic /and/ enforcement has gone to nothing. The only time I see people get pulled over now is in speedtrap small towns.
Enough events should show clusters where potholes likely exist. You would think cities would love that kind of data.
I spend most of my time in California, have lived in SoCal and NorCal, and I spend a fair chunk of time driving around Virginia. My guess is that there's something fishy with the Virginia data being reported. Because if there is anyplace on earth with an insane number of controlled access roads, it's gotta be NVA/DC metro area (or the Tri-Border Area as I like to call it).
Also, they need to either update the caption for Figure 4, or move the plots to correspond with the caption. Clearly the Virginia data is on top (or the code is wrong, which seems exceedingly unlikely).