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I am a traffic engineer and one of the things that I do regularly is write 10 year traffic plans for small to medium sized cities, think 60,000 people max. When

I am a traffic engineer and one of the things that I do regularly is write 10 year traffic plans for small to medium sized cities, think 60,000 people max. When a lot of the self driving hype was really kicking off, I was told to make sure to incorporate them into the plans. This mostly consisted of a few sentences about self driving and that was it. When modeling future traffic growth, the client would always say, "these numbers a pretty high, do you thing self driving cars will lower them?" To which I would respond that it is doubtful. I am in the rural west where cars are a large part of life. Ride sharing and public transportation are rarely a thing outside of the core of towns. The idea of a self driving car that one doesn't own would be very odd to a lot of people in this area. On top of the social side of things, the roads are not in great shape in northern climates and many of the visual cues that we use to drive can be missing or very hard to see for many miles. Striping delineating the edge of the road often gets worn away over the course of a few years and doesn't get re-painted for a few more. Some major roads connecting two towns may not even have a paved shoulder, just 24 feet of asphalt with a stripe down the middle. (For reference, 12 foot lanes with 4 foot shoulders are the general norm for this part of the US.) All of this and I have still yet to touch on weather. I look forward to self driving cars. However, I don't think that they are going to solve many of our traffic issues outside of urban cores. For me, the incremental steps to reach self driving will result in fewer injuries and fatalities on our roadways, and that is a win.

chrisco255 7y ago
Yeah just collision detection and lane guidance are already helpful in modern cars. After driving in snow in Colorado I have to wonder how self driving cars perform under such conditions. I couldn't make out where the lines are and no one really does. A four lane road can easily become a two lane road under such conditions, as people cut a worn path through the snow. I really think self driving could improve public transportation in urban cores by tracking preset paths. I could also imagine buses that are mostly autonomous, but where a remote driver could override the controls for exceptions.
- throwawayhhakdl 7y ago
  A lot of people are incredibad at driving in snow. I would not be surprised at all if self driving cars vastly reduce the accidents attributable to snow on the road. Some of that might be due to the car deciding something is too dangerous to attempt, and frankly that seems fine to me. If your problem is “the car can’t handle x condition”, there’s really no issue so long as that’s because the car refuses to try, rather than trying and failing with non trivial probability
manmal 7y ago
It will also restore mobility for many people who cannot drive yet or not anymore. Where I live, Taxis and Ubers are still too expensive and not ubiquitous enough to replace an owned car.
- takk309 7y ago
  This is one of the most important use cases I can see for self driving cars. As it is, on demand transit is expensive and in rural areas not the most frequent. For example the northern portion of Montana has a very low population spread out across a large distance. For many elderly to get medical care they must travel 100-200 miles to the nearest hospital. When they have to make this trip every week, I can be a massive burden on their loved ones. On demand transit is an option but may only run a couple times a week due to limited drivers. A self driving vehicle would help this situation a lot.
- Johnny555 7y ago
  I'm counting on self-driving cars to be viable by the time I'm too old to drive -- it was very hard for my grandmother to give up her car and it took a lot of coaxing (and a little sabotage of her car to make her think it needed expensive repairs) to get her to stop driving. But it was necessary because she was becoming a dangerous driver.
skywhopper 7y ago
I'm always baffled by folks who assume self-driving cars would reduce traffic. No matter what, even if they are privately owned, truly self-driving vehicles could only increase traffic. If they can be dispatched without a human driver to pick up groceries or take-out, for example, there'll be a lot more trips. And sharing self-driving cars rather than owning them would surely be more likely to increase the number of cars on the road since they have to make a trip to pick you up and another one after they drop you off.
- takk309 7y ago
  The rationale I have heard is that a single car could be used to make a multiple chained trips instead of multiple cars making multiple trips. This is the same idea behind ride sharing. I feel this breaks down with privately owned vehicles. I do see an increase in traffic in areas with expensive parking. Specifically I would sent my car to a cheaper lot and that would result in an additional trip. Even worse, that would be a zero occupancy trip.
  - ghaff 7y ago
    I'm also pretty sure it will increase commutes and this applies even if self-driving isn't fully door to door. There are probably a lot of people who would hesitate to do an hour car commute today who would be a lot more open to a 60 or even 90 minute commute of something else is doing the driving.
- ctdonath 7y ago
  I envision herds of driverless vehicles slowly cruising randomly, summoned when needed, avoiding the cost of parking.
  - takk309 7y ago
    Possibly the a horror worse than Skynet!
seanmcdirmid 7y ago
> "these numbers a pretty high, do you thing self driving cars will lower them?" My answer would be no: the opposite, if self driving cars work out, people will probably just drive more! The only traffic gains would come from 100% self driving cars that could then be optimized somewhat globally.
xiaolingxiao 7y ago
hey Takk309 could I reach out to you to ask a few question? I am researching what it takes to validate the safety of these cars on the street in relation to other cars, and pedestrians, and your background would be immensely helpful! Feel free to email me at lingxiao@seas.upenn.edu
- takk309 7y ago
  That is going to be a tough but to crack. Crash statistics are tricky because they are either underreported or very infrequent. Two good resources for just about anything traffic related are ITE [1] and TRB [2]. [1] https://www.ite.org/ https://www.ite.org/ [2] http://www.trb.org/ http://www.trb.org/
  - xiaolingxiao 7y ago
    Hm for sure that's why it's exciting and super important from a technical standpoint! I'm interested in learning more about how city planners think about traffic in general, so that's why I think learning from your perspective would be super helpful, and obviously super happy to share my perspective on the field, most of my friends work at one of these storied companies so I have a slightly different vantage point.

chrisco255 7y ago

Yeah just collision detection and lane guidance are already helpful in modern cars. After driving in snow in Colorado I have to wonder how self driving cars perform under such conditions. I couldn't make out where the lines are and no one really does. A four lane road can easily become a two lane road under such conditions, as people cut a worn path through the snow. I really think self driving could improve public transportation in urban cores by tracking preset paths. I could also imagine buses that are mostly autonomous, but where a remote driver could override the controls for exceptions.

throwawayhhakdl 7y ago
A lot of people are incredibad at driving in snow. I would not be surprised at all if self driving cars vastly reduce the accidents attributable to snow on the road. Some of that might be due to the car deciding something is too dangerous to attempt, and frankly that seems fine to me. If your problem is “the car can’t handle x condition”, there’s really no issue so long as that’s because the car refuses to try, rather than trying and failing with non trivial probability

manmal 7y ago

It will also restore mobility for many people who cannot drive yet or not anymore. Where I live, Taxis and Ubers are still too expensive and not ubiquitous enough to replace an owned car.

takk309 7y ago
This is one of the most important use cases I can see for self driving cars. As it is, on demand transit is expensive and in rural areas not the most frequent. For example the northern portion of Montana has a very low population spread out across a large distance. For many elderly to get medical care they must travel 100-200 miles to the nearest hospital. When they have to make this trip every week, I can be a massive burden on their loved ones. On demand transit is an option but may only run a couple times a week due to limited drivers. A self driving vehicle would help this situation a lot.
Johnny555 7y ago
I'm counting on self-driving cars to be viable by the time I'm too old to drive -- it was very hard for my grandmother to give up her car and it took a lot of coaxing (and a little sabotage of her car to make her think it needed expensive repairs) to get her to stop driving. But it was necessary because she was becoming a dangerous driver.

skywhopper 7y ago

I'm always baffled by folks who assume self-driving cars would reduce traffic. No matter what, even if they are privately owned, truly self-driving vehicles could only increase traffic. If they can be dispatched without a human driver to pick up groceries or take-out, for example, there'll be a lot more trips. And sharing self-driving cars rather than owning them would surely be more likely to increase the number of cars on the road since they have to make a trip to pick you up and another one after they drop you off.

takk309 7y ago
The rationale I have heard is that a single car could be used to make a multiple chained trips instead of multiple cars making multiple trips. This is the same idea behind ride sharing. I feel this breaks down with privately owned vehicles. I do see an increase in traffic in areas with expensive parking. Specifically I would sent my car to a cheaper lot and that would result in an additional trip. Even worse, that would be a zero occupancy trip.
- ghaff 7y ago
  I'm also pretty sure it will increase commutes and this applies even if self-driving isn't fully door to door. There are probably a lot of people who would hesitate to do an hour car commute today who would be a lot more open to a 60 or even 90 minute commute of something else is doing the driving.
ctdonath 7y ago
I envision herds of driverless vehicles slowly cruising randomly, summoned when needed, avoiding the cost of parking.
- takk309 7y ago
  Possibly the a horror worse than Skynet!

seanmcdirmid 7y ago

> "these numbers a pretty high, do you thing self driving cars will lower them?" My answer would be no: the opposite, if self driving cars work out, people will probably just drive more! The only traffic gains would come from 100% self driving cars that could then be optimized somewhat globally.

xiaolingxiao 7y ago

hey Takk309 could I reach out to you to ask a few question? I am researching what it takes to validate the safety of these cars on the street in relation to other cars, and pedestrians, and your background would be immensely helpful! Feel free to email me at lingxiao@seas.upenn.edu

takk309 7y ago
That is going to be a tough but to crack. Crash statistics are tricky because they are either underreported or very infrequent. Two good resources for just about anything traffic related are ITE [1] and TRB [2]. [1] https://www.ite.org/ https://www.ite.org/ [2] http://www.trb.org/ http://www.trb.org/
- xiaolingxiao 7y ago
  Hm for sure that's why it's exciting and super important from a technical standpoint! I'm interested in learning more about how city planners think about traffic in general, so that's why I think learning from your perspective would be super helpful, and obviously super happy to share my perspective on the field, most of my friends work at one of these storied companies so I have a slightly different vantage point.