Speaker 1: Hey, Welcome to Sign Stuff, the production of iHeartRadio More. Hey,
Speaker 1: cham and today we're answering the question what really makes
Speaker 1: traffic so bad? It turns out it's not careless drivers
Speaker 1: or accidents or roadwork. It's something much more surprising. We're
Speaker 1: going to talk to two experts on traffic engineering. We're
Speaker 1: going to step us through the history of traffic, the
Speaker 1: real causes of it, and what we can do to
Speaker 1: make commuting easier. To hit the accelerator because we are
Speaker 1: clearing the road to answer the question what really makes
Speaker 1: traffic that enjoy? Hey everyone? So, like most people, I
Speaker 1: hate traffic. I always feel like I'm wasting my life
Speaker 1: away sitting in my car, hitching my way across the
Speaker 1: highway or a busy road. And the worst part is
Speaker 1: that sometimes there's no clear reason for it. You've probably
Speaker 1: had the experience of sitting in traffic for a while
Speaker 1: and then all of a sudden, the traffic clears up,
Speaker 1: and you think was it all for nothing? What's going on? Well,
Speaker 1: to find out why that happens and to answer all
Speaker 1: my traffic related questions, I reached out to two traffic
Speaker 1: engineering experts. The first one is doctor Maria Lauda de
Speaker 1: la Monice, a professor of civil and environmental engineering at
Speaker 1: the University of California at Berkeley who works at the
Speaker 1: no pun intended intersection between traffic science and math. She's
Speaker 1: going to tell us why these random traffic jams happen,
Speaker 1: but first I wanted to know a little bit about
Speaker 1: the history of traffic. So here's my conversation with doctor
Speaker 1: Maria Lauda de la Monique. Well, thank you, doctor de
Speaker 1: le Monique for joining us.
Speaker 2: Thank you, it's a pleasure to a here.
Speaker 1: Well, I kind of have to apologize for being laid.
Speaker 1: I was stuck in traffic.
Speaker 3: That seems to be a problem for everybody these days,
Speaker 3: especially in the Bay Area where we are.
Speaker 1: Actually, I'm just kidding. I work from home, so I
Speaker 1: haven't had to deal with traffic in a long time.
Speaker 3: I bike to avoid the traffic. I have an electric bike.
Speaker 3: That's my commute.
Speaker 1: Oh that's smart. Wow, at least for now, until everybody
Speaker 1: gets an electric bike, Yes, then there might be bike traffic.
Speaker 3: Yeah, there's still is some places in Europe. Alreadia experience
Speaker 3: in traffic with bikes in the Netherlands. In Paris, it
Speaker 3: was a problem for a bit.
Speaker 1: Oh wow, all right, we'll get into that, but I
Speaker 1: thought way we could start by asking you to tell
Speaker 1: us a little bit of the history of traffic, Like
Speaker 1: when did traffic become a problem for humans.
Speaker 3: Well, people tend to think that traffic was born, let's say,
Speaker 3: with cars, but in reality it's something that all does
Speaker 3: humans and cities. So we can go as far back
Speaker 3: as ancient Rome and we still have traffic and congestion.
Speaker 3: There's Julius sister, even have the regulatory intervention to avoid
Speaker 3: that commercial trucks or commercial cars will go on through
Speaker 3: the city during daytai because they would cause congestion and
Speaker 3: they would make too much noise. So it's a very
Speaker 3: whole problem and we're still here trying to solve it.
Speaker 1: It's oldest Roman empire, yes, yes, And then a city
Speaker 1: started to grow, we also started to experience more and
Speaker 1: more traffic and different type of traffic.
Speaker 3: Obviously, with the advent of cars is when the problem
Speaker 3: became very big because a lot of cars that are
Speaker 3: in the road, and also became apparent that the road
Speaker 3: cannot be shared anymore between pedestrians and cars, right where
Speaker 3: before it was the case everybody was in their pedestrian, bicycle,
Speaker 3: animal power vehicles, and then since the cars were there,
Speaker 3: and then it became a very chronic problem. And now
Speaker 3: it became a problem of everybody going to work in
Speaker 3: the morning at the same time and being stuck in traffic.
Speaker 2: When we built freeways.
Speaker 3: In the fifties, now people didn't live anymore in the city,
Speaker 3: but now they had to take the freeway to go
Speaker 3: to the world, and now freeway became congested. And so
Speaker 3: it's a problem that we've been dealing for a long time.
Speaker 1: Who it seems like any time you try to do
Speaker 1: something about it, it still manages to come back.
Speaker 3: Yes, because it seems the more we make it better,
Speaker 3: the more we make people want to use the cars,
Speaker 3: and so instead like we build more roads and then
Speaker 3: people use more cars instead of like fixing what we
Speaker 3: had before.
Speaker 1: And so that seems like a very human problem, is
Speaker 1: it is, Well, can you take me back a little
Speaker 1: bit on the history of I guess, trying to manage
Speaker 1: traffic or trying to deal with traffic, Like what did
Speaker 1: the Romans do?
Speaker 3: So before the cars, what people were trying to do,
Speaker 3: it's mostly intervened like on the human behavior. So it's
Speaker 3: like forbid the use of cars during daytime, right, and
Speaker 3: so you can only go in the city during nighttime
Speaker 3: when there was animal power vehicles. So there may be
Speaker 3: a road becomes a one way road, or you had
Speaker 3: a policeman at an intersection that decides, like you know,
Speaker 3: now it's animal power flow that goes through the intersection,
Speaker 3: then it's pedestrian.
Speaker 2: Then as whatever else.
Speaker 3: As technology has gotten better and better, we're also getting
Speaker 3: better and better and managing traffic. So as car came on,
Speaker 3: also traffic light came on because now we were suddenly
Speaker 3: able to measure traffic. And the way to measure traffic
Speaker 3: at the beginning of the nineteen hundred was a man
Speaker 3: standing on the side of the road and literally counting
Speaker 3: car as time.
Speaker 1: Passed, right, And so graduate student, I imagine.
Speaker 3: At the time it was actually scientists, like there's this
Speaker 3: famous picture of Bruce Greenshield as one of the fathers
Speaker 3: of traffic flow theory, that's standing on the side of
Speaker 3: the road with a camera and counting cars in the
Speaker 3: nineteen thirties or something. And so the idea it became
Speaker 3: managed traffic. The same way as we can measure traffic,
Speaker 3: we place traffic lights and traffic lights allow us to
Speaker 3: have a certain amount of cars per hours. And if
Speaker 3: they are in the cities, you have traffic light and intersection.
Speaker 3: If we are in freeway, then you're going to have
Speaker 3: a traffic light at the entrance of an intersection.
Speaker 2: And it becomes what is known as from metering.
Speaker 3: As we've gotten better and getting data and we have
Speaker 3: more information. So now we have, for example, data on
Speaker 3: sensors on roadsides, or for example, we have vehicles that
Speaker 3: give us information about the GPS or the phone. Then
Speaker 3: we've gotten also better and managing traffic, and so now
Speaker 3: you have city wide traffic lights plans, or you had
Speaker 3: for example, what is variable to p limit, which I'm
Speaker 3: sure everybody at some point you saw this message panel
Speaker 3: on the freeway that says slow down and go at forty.
Speaker 2: Miles an hour.
Speaker 3: And so how we manage traffic has evolved throughout the year,
Speaker 3: and it's going to evolve as we have different types
Speaker 3: of measurements and different ways of estimating traffic.
Speaker 1: It seems like the traffic light was a big innovation.
Speaker 1: Do we know anything about the history of the traffic light?
Speaker 3: So the first traffic light that I know of dates
Speaker 3: back to the beginning of the nineteen hundred and I
Speaker 3: think it's in Cleveland. At the beginning was exactly that,
Speaker 3: like a single traffic light that would just manage traffic
Speaker 3: at a single intersection. And then as things have evolved
Speaker 3: nowadays we're able also to have traffic lights that are
Speaker 3: synchronized and have the so called the green waves in
Speaker 3: which you hit green at first traffic lights and then
Speaker 3: you're able to go through all the intersections with that
Speaker 3: green light and all of that.
Speaker 1: I see. So that's a little bit of the history
Speaker 1: of traffic science and engineering. But here's the big question,
Speaker 1: why is this problem so hard to fix? Can we
Speaker 1: just build wider roads? Well, it turns out there is
Speaker 1: an answer to that question, and it's something that totally shocked.
Speaker 1: I learned it while talking to the next expert on
Speaker 1: our show today, Callin Mees. Well, thank you so much
Speaker 1: for joining us, Miss mess.
Speaker 4: Thanks for having me. I'm excited to be here.
Speaker 1: Can you please tell U who you are and what
Speaker 1: you do.
Speaker 4: Sure. My name is Colin Mess and I am a
Speaker 4: PhD candidate at the University of Delaware in the Civil,
Speaker 4: Environmental and Construction Engineering Department. My research focuses on traffic
Speaker 4: congestion and applying new methods such as artificial intelligence to
Speaker 4: enhance traffic management and response to incidents.
Speaker 1: Very cool, bite the start us off. He tell us
Speaker 1: why is traffic so bad? Sometimes?
Speaker 4: Sure, traffic congestion is bad generally as a cause of,
Speaker 4: you know, at the highest level, a mismatch between supply
Speaker 4: and demand. So we can't build our way out of congestion,
Speaker 4: so to speak, as a phrase, you hear a lot
Speaker 4: in traffic engineering, and we try to design the roads
Speaker 4: in a way that we can accommodate a large part
Speaker 4: of the demand we would see even during rush hour periods.
Speaker 4: But we can't design the road for you know, the
Speaker 4: busiest day of the year economically or feasibly. And so
Speaker 4: depending on things you know that are going on, whether
Speaker 4: there's a special event or an incident, or the weather
Speaker 4: is really nice and people are traveling due to the season,
Speaker 4: we will always inevitably have some congestion as a result
Speaker 4: of the fact that we just can't build an infinitely
Speaker 4: sized road.
Speaker 1: Oh that's interesting. I hadn't heard of that idea before.
Speaker 1: So what do you mean by economically we can't build
Speaker 1: the roads beginnough.
Speaker 4: On the one hand, I think the biggest concern regarding
Speaker 4: that would be space, in that we we want to
Speaker 4: build roads, hopefully in a way that has a minimal
Speaker 4: impact on everyday life and people, that minimizes the environmental impact.
Speaker 4: And so it would be nice if we had you know,
Speaker 4: infinite space and could build floating roads that would really
Speaker 4: minimize the impact on the local environment in the region.
Speaker 4: But until we can do that, sadly, we have to
Speaker 4: make a compromise in some respect to how much capacity
Speaker 4: we can build into the road given the you know,
Speaker 4: constraint from the land perspective and the environmental perspective.
Speaker 1: Uh. It's like, even if we know that in a
Speaker 1: certain road or a certain section of a city or
Speaker 1: a town there's going to be two hundred cars going
Speaker 1: through a peak rush hour, we don't typically design the
Speaker 1: road to be able to take two hundred cars an hour. Yes, exactly.
Speaker 4: We would try to get as close to that as
Speaker 4: we possibly could, and in some cases we can build
Speaker 4: to accommodate the expected rush hour congestion.
Speaker 1: Interesting, it's like, even if we let's say, had infinite
Speaker 1: land to build a twenty lane road a, it may
Speaker 1: not make sense to design it so that it can
Speaker 1: take peak rush hour traffic because most of the time
Speaker 1: is not peak rush hour traffic.
Speaker 4: Yes, exactly, And similar to how we build parking lots,
Speaker 4: we try to build for the thirtieth busiest day of
Speaker 4: the year, so hopefully we're encapsulating the vast majority of
Speaker 4: the regular traffic on that road through a model like that.
Speaker 4: But unfortunately, if we built for the you know, for
Speaker 4: the one percent or busiest day of the year, we
Speaker 4: likely it would not be feasible from some perspective, whether
Speaker 4: that's you know, environmental due to the space constraints, or
Speaker 4: maybe it's just an economic cost that would be too
Speaker 4: high to be supported with the resources we have.
Speaker 1: Oh, the parking lot is a really good analogy. What
Speaker 1: do you mean that you might design it for the
Speaker 1: thirty if you said.
Speaker 4: Yeah, So if we look at the entire year, cross
Speaker 4: all seasons and estimate what the demand or usage might
Speaker 4: be of the road or the parking lot, a lot
Speaker 4: of times the planners will pick the thirtieth busiest day
Speaker 4: of the year as a good benchmark. And that's usually
Speaker 4: the reason for that is because the thirtieth busiest day
Speaker 4: is if you look at the pattern in traffic graph,
Speaker 4: it would be where things start to really level off,
Speaker 4: and then you could almost consider the twenty nine other
Speaker 4: days as a rare incident or a rare case. For example,
Speaker 4: by me, we have a lot of travel down to
Speaker 4: the beach for during the summer. A lot of people
Speaker 4: live down at the beach for three or four months
Speaker 4: of the year, and that's a great example of a
Speaker 4: place where we can't really design the road for just
Speaker 4: those two months because the utilization outside of those few
Speaker 4: months it's significantly lower, maybe eighty percent lower, as just
Speaker 4: a really rough estimate, so it wouldn't make sense from
Speaker 4: an investment perspective, especially if we have to divide a
Speaker 4: limited amount of money across many projects throughout the state,
Speaker 4: not just in the beach area.
Speaker 1: Wow, that's fascinating. He just kind of blew my mind, Colin.
Speaker 4: Yeah. You know, a lot of times you'll see, like
Speaker 4: I know, I'll travel down a highway and it'll be
Speaker 4: congested and I'll just see completely empty open space on
Speaker 4: either side while I'm you know, on the road congested,
Speaker 4: and I feel like a lot of people see that
Speaker 4: and think, well, why didn't they just build the road
Speaker 4: with more lanes. Yeah, I wish we could do that
Speaker 4: every time. It would definitely save a lot of headache.
Speaker 4: But yeah, just the real world challenges always make things
Speaker 4: a little more difficult than expected.
Speaker 1: It's kind of like an almost effective life.
Speaker 4: Yeah, I would agree with that.
Speaker 1: Yeah, Okay, this really blew my mind. What Colin you're
Speaker 1: saying is that the real reason we have traffic jams
Speaker 1: is because we want to have them. Yes, the general
Speaker 1: cost of traffic is that there are more cars trying
Speaker 1: to get through a road than the road has space for.
Speaker 1: But then why don't we just build bigger roads? Well,
Speaker 1: the real reason is that we choose not to. It
Speaker 1: doesn't make sense economically to build roads for the absolute
Speaker 1: worst traffic days of the year, because then most of
Speaker 1: the time the roads would be mostly empty. Instead, we
Speaker 1: make a compromise. We accept that there are going to
Speaker 1: be traffic jams some of the time to minimize the
Speaker 1: cost and the burden of building bigger roads. So living
Speaker 1: with traffic is a choice. Okay, So that's kind of
Speaker 1: the real reason traffic exists. There are sometimes too many cars,
Speaker 1: and we choose not to build roads that can take
Speaker 1: all those cars. But here's the thing. As annoying as
Speaker 1: it is to send in your car in a congested road.
Speaker 1: There is something even worse about the problem of traffic,
Speaker 1: and it's something that we definitely can't predict, but that
Speaker 1: AI could potentially help us solve in the future. So
Speaker 1: when we come back, we'll talk about what that is
Speaker 1: and something called phantom traffic jams. So don't get off
Speaker 1: the freeway just yet. Stay with us. We'll be right back. Hey,
Speaker 1: we'll come back. We're talking about the real reasons traffic
Speaker 1: is bad, and so far we talked about how it's
Speaker 1: a basic supply and demand problem. There are sometimes too
Speaker 1: many cars and not enough road to fit them all.
Speaker 1: But here's a shocker. Roads are usually not designed to
Speaker 1: handle peak traffic demand. It would be too expensive and
Speaker 1: take up too much space to make roads and highways
Speaker 1: big enough to handle the worst case traffic scenarios. So
Speaker 1: in a way, traffic jams are sort of built into
Speaker 1: our society, and according to the experts we're talking to
Speaker 1: you today, part of the is that it's hard to
Speaker 1: even know what the worst traffic scenario is going to be.
Speaker 1: Here's traffic science researcher Colin Meess.
Speaker 4: Another issue there is that the roads take time to build,
Speaker 4: and we find that travel demand patterns change very quickly
Speaker 4: and suddenly, and so one issue would be that we
Speaker 4: might design the road for the geek rush hour at
Speaker 4: the time of building, and we'll project out based on
Speaker 4: how we see the population changing and try to get
Speaker 4: it as close as possible. But some road projects might
Speaker 4: take twenty years to build. For example, there's a road
Speaker 4: near me called the four seventy six where they basically
Speaker 4: ran into that issue. It took about twenty years to
Speaker 4: build this project, and by the time the project was built,
Speaker 4: the population had increased to a point where the road
Speaker 4: was instantly congested. It's almost overnight, No, it's open to
Speaker 4: the public, and there's already a congestion on that road
Speaker 4: from day one.
Speaker 1: Oh wow, it was sort of like a it was
Speaker 1: obsolete from the get gode that it was opened exactly.
Speaker 4: And I'm sure the people working on that project, you know,
Speaker 4: projected out thirty years, use the best population models they
Speaker 4: could to try to really estimate how many lanes they
Speaker 4: could build or how many lanes they should build, and
Speaker 4: what the throughput of that road should be. But unfortunately
Speaker 4: the models are not always correct, especially when it comes
Speaker 4: to modeling human traffic.
Speaker 1: Wow, Yeah, sometimes we don't know how much traffic there's
Speaker 1: going to be in the future exactly.
Speaker 4: So in the case of that road, that road was
Speaker 4: built to help specifically commuters coming from a residential area
Speaker 4: that was about forty five minutes away from the central
Speaker 4: business district where they worked, and because the traffic was
Speaker 4: so bad, a lot of people over time changed how
Speaker 4: they got to work, whether that was using maybe some
Speaker 4: kind of carpooling system, or maybe they were using the
Speaker 4: public transit like the metro or trains to get there,
Speaker 4: or they move closer to the city and use they
Speaker 4: bike or something like that. And then when that new
Speaker 4: road opens up, word spreads that hey, this new route
Speaker 4: is great, you can take your car into the city
Speaker 4: again with no problem, and very quickly people will then
Speaker 4: shift their travel patterns from these alternate modes that they
Speaker 4: may have been using. And so when that option becomes available,
Speaker 4: you can see a shift in demand that may not
Speaker 4: have been able to be predicted just looking at things
Speaker 4: like population change and the amount of vehicles being registered
Speaker 4: in area.
Speaker 1: WHOA, it's super dynamic exactly.
Speaker 4: That's a great way to say accounting for human behavior
Speaker 4: can be so difficult.
Speaker 1: Right, That's kind of the problem is trying to predict
Speaker 1: what people are going to do exactly.
Speaker 4: I feel like, well, we will always have this challenge
Speaker 4: to some extent.
Speaker 1: So traffic seems almost like a fact of life. But
Speaker 1: here's the thing. Traffic by itself is not considered the
Speaker 1: real problem. Most people don't mind a little bit of traffic.
Speaker 1: The problem, according to our experts, is something else.
Speaker 4: The interesting thing about congestion to me is that I
Speaker 4: feel like everybody expects congestion, right Like, if you're traveling
Speaker 4: a route during rush hour, you have an expectation that
Speaker 4: you will be sitting in some level of congestion. But
Speaker 4: I think what really frustrates people for good reason is uncertainty.
Speaker 4: And I think if you asked a lot of people,
Speaker 4: would they rather have a trip that they know to
Speaker 4: work their commute's always going to be around thirty five minutes,
Speaker 4: give or take, or some days it's twenty minutes and
Speaker 4: some days it's fifty five. I think they would almost
Speaker 4: always rather have the certainty that they can plan around
Speaker 4: that I know that I'm going to my route's going
Speaker 4: to take thirty five minutes, even if it's a little
Speaker 4: longer than it could take. As long as it's consistent.
Speaker 4: That's really important for people to be able to, you know,
Speaker 4: plan and go about their lives and plan their travel.
Speaker 1: Oh, that's another super fascinating point. The problem with traffic
Speaker 1: is not that there is traffic, because people are to
Speaker 1: some degree okay with planning around it. It's the uncertainty
Speaker 1: that's really frustrating.
Speaker 4: Yeah, I would say from the people that I've talked
Speaker 4: to and just my lived experience, that's what frustrates the
Speaker 4: majority of people, in myself the most. I remember when
Speaker 4: I used to commute into the city. On a good day,
Speaker 4: it would take thirty five minutes to get to work,
Speaker 4: but on a bad day, it could take an hour
Speaker 4: and a half. And you know, when you have it,
Speaker 4: there's an expectation that I'm arriving at a certain time,
Speaker 4: and so when the travel time is that unreliable, it
Speaker 4: becomes unfortunate because I basically have to plan for the
Speaker 4: worst case scenario, and then I may arrive, you know,
Speaker 4: an hour earlier than I needed. And that's you know,
Speaker 4: nobody wants to arrive to work an hour earlier if
Speaker 4: they don't need to, So I feel like that is
Speaker 4: one of the most frustrating pain points of traffic congestion.
Speaker 1: Right right, or the opposite where you know, you plan
Speaker 1: for the average, but then you're late because there's more
Speaker 1: traffic than.
Speaker 4: Usual exactly and maybe nine at a ten times you
Speaker 4: leave with the expectation that it's going to take thirty
Speaker 4: five minutes, and nine out of ten times it does,
Speaker 4: but one out of ten times it's three times as long.
Speaker 4: And I mean, you can only explain that to your
Speaker 4: boss so many times before there's no you know, excuse,
Speaker 4: and you just have to leave earlier and plan for
Speaker 4: the worst case, which is unfortunate.
Speaker 1: Okay, I guess then the question is what causes that
Speaker 1: uncertainty in traffic congestion.
Speaker 4: So I think traffic incidents are one of the biggest
Speaker 4: drivers of cong unexpected congestion. And by a traffic incident,
Speaker 4: in my line of work, we call them non recurrent events.
Speaker 4: So we would call like rush hour recurring traffic, or
Speaker 4: like a seasonal change due to like we talked about
Speaker 4: people going down to the beach, that would be something
Speaker 4: that you could call recurrent traffic because we expect it,
Speaker 4: we can plan for it, and we kind of know
Speaker 4: it's happening. But with an incident we would call that
Speaker 4: non recurring congestion, and that could be anything from unexpected
Speaker 4: inclement weather that reduces visibility and overall would lower the
Speaker 4: average speed traveled on the road, which would then effectively
Speaker 4: lower our capacity temporarily. It could also be, of course,
Speaker 4: things like a traffic accident or a work zone where
Speaker 4: the capacity is essentially temporarily altered. So a vehicle gets
Speaker 4: in an accident and we need time for that vehicle
Speaker 4: to get moved out of the lane that it's blocking.
Speaker 4: And while that's happening, say it's a three lane road
Speaker 4: and one lane's blocked, we're effectively reducing our capacity by
Speaker 4: at least thirty three percent. We can't really plan for
Speaker 4: an unexpected incident, right, These are things where we can't
Speaker 4: plan around them and prevent them.
Speaker 1: I see. It's sort of like there's two sources of
Speaker 1: traffic or congestion, Like there's a base level of traffic
Speaker 1: that's just due to the like you said, the recurring causes,
Speaker 1: which are you know, just not enough supply to meet.
Speaker 4: The demand exactly.
Speaker 3: Yeah.
Speaker 4: I think that's a good way to think about it,
Speaker 4: almost as like two different types of congestion, two distinct
Speaker 4: different types and the non recurring congestion I feel like
Speaker 4: is the most frustrating for people because it really does
Speaker 4: play into the travel time reliability. So you know, it
Speaker 4: really impacts reliability in a way that you're just not
Speaker 4: expecting at all.
Speaker 1: Okay, so there's general traffic just from having too many
Speaker 1: cars in the road, but then that you can have
Speaker 1: extra unexpected traffic because of accidents or cars breaking down,
Speaker 1: or construction or weather. Those can be frustrating, but maybe
Speaker 1: not as frustrating as the congestion that someplace seems to
Speaker 1: happen for no reason at all. You know, when there's
Speaker 1: a big slowdown but there isn't an accident or a
Speaker 1: car broken down, or whether someplace cars just seem to
Speaker 1: jam up, and that is actually a well studied phenomenon
Speaker 1: in traffic science called phantom traffic. To explain this, here's
Speaker 1: doctor Maria Lauda di la Monarky.
Speaker 2: For me, it's much more interesting is what we call
Speaker 2: phantom traffic jams.
Speaker 1: Phantom traffic jams, yes, like a ghost like.
Speaker 2: Ghosts, because they appear out of nowhere.
Speaker 3: I'm sure everybody that is driven in the freeway have
Speaker 3: lived this. At some points, you're stuck in traffic, and
Speaker 3: you start accelerating and breaking, accelerating and breaking constantly, and
Speaker 3: an all a sudden we are out of it and
Speaker 3: there's nothing inside that could have caused us. There's no accident,
Speaker 3: there's no worksite constructions, not even run shower right, And
Speaker 3: this happened just because we assume intend to get distracted. Well,
Speaker 3: we're driving, and then all of a sudden we realized
Speaker 3: that OOPS were too close to the Kara had, so
Speaker 3: we slightly it up on the brake, and that creates
Speaker 3: a ripple effect that fifteen minutes later, someone else is
Speaker 3: crossing the same freeway and alives at that point is
Speaker 3: gonna be stuck in stop and go.
Speaker 1: Traffic fifteen minutes later, even up.
Speaker 2: To fifteen it can be even longer than that.
Speaker 1: Yes, whoa one simple distraction I got a text message
Speaker 1: or I'm scrolling through Instagram and instead of paying attention
Speaker 1: can ruin someone today twenty minutes later.
Speaker 3: Yes, we call it either stopping away more fun on
Speaker 3: traffic jam because they are not caused by any physical rism,
Speaker 3: and there's no physical rism for them to appear, not
Speaker 3: physical obstacle.
Speaker 1: A list in the road, I see, So it's just
Speaker 1: human sloppiness. Yes, let's say traffic gets flowing smoothly. What's
Speaker 1: going to cause it to suddenly not be smooth?
Speaker 3: It's as simple as one driver slightly tapping on the brake.
Speaker 3: He taps on the brake because for whatever reason, and
Speaker 3: let's say it sees that is too close with the
Speaker 3: car ahad, But it can simply be just not come
Speaker 3: from the speed is going, so slightly up on the
Speaker 3: brakes and then like the driver slightly tapping on the
Speaker 3: brake creates basically a little disturbance, and that disturbance can templify.
Speaker 3: That means that the driver behind the first driver is
Speaker 3: gonna have to slightly up on the brake a bit more.
Speaker 3: The third one is gonna tap on the brake harder
Speaker 3: and harder, and harder and harder, until the last one
Speaker 3: is gonna have to basically stop, almost stop or brake
Speaker 3: so hard that the car stopped or you end up stopping,
Speaker 3: and that basically creates the stopping.
Speaker 1: Why does it get worth each time because it's a delay.
Speaker 2: Because there's a delay, there's the reaction time of the drivers.
Speaker 3: There's delay that comes from the kra had to a
Speaker 3: car behind, So by the time you realize that the
Speaker 3: kara had break, you have to break as well, and
Speaker 3: you're still going in the speed of before, so now
Speaker 3: you have to break a bit harder respect the car had.
Speaker 1: Oh it's no balls, it's no balls exactly, yes, And
Speaker 1: is it also the same for accelerating.
Speaker 3: It's the same with accelerating, like if you try to
Speaker 3: catch up with the person in front of you. So
Speaker 3: this is what happened in the phantom traffic jam, right,
Speaker 3: So you go into this period of breaking where everybody
Speaker 3: breaks and the last vehicle has to break the hardest.
Speaker 3: But then everybody tries to catch up with the vehicle
Speaker 3: in front of it. So everybody accelerate, accelerate, and the
Speaker 3: last vehicle acces accelerate the most because it is to
Speaker 3: catch up to the previous vehicle, which is counterintuitive from
Speaker 3: what you're supposed to do. You're supposed to like just
Speaker 3: stay at your constant speed and if it's safe to
Speaker 3: do so.
Speaker 1: It just low everybody down, yes or no, good exactly exactly.
Speaker 1: It's getting distracted or it's just human reaction time.
Speaker 2: It's a mike, sure of both. Sometimes it's because you're distracted.
Speaker 2: Sometimes it's just utilized.
Speaker 1: Too late makes me think we should just let the
Speaker 1: robots drive. Everyone should let the robot car drive. This
Speaker 1: brings us to the next big question about all of this.
Speaker 1: Could robots or AI solve the traffic problem? What if
Speaker 1: everyone drove self driving cars with that get rid of
Speaker 1: traffic jams? Or what if we put an AI in
Speaker 1: charge of our traffic light system? Would that create a
Speaker 1: perfect road system. When we come back, I'll ast car
Speaker 1: experts all these questions and we'll see if it puts
Speaker 1: them in a jam. So stay with us and we'll
Speaker 1: be right back. Hey, welcome back. We're talking about the
Speaker 1: science of traffic, and so far we've talked about what
Speaker 1: really causes traffic and about how the real problem with
Speaker 1: it is the uncertainty of it. We also talked about
Speaker 1: something called phantom traffic, which is a big source of
Speaker 1: unexpected congestion in our roads. Now the question is what
Speaker 1: can we do about all this uncertainty. What are ways
Speaker 1: we can make traffic or tolerable. As it turns out,
Speaker 1: one of our experts today has been at the head
Speaker 1: of a project to use robots to make the flow
Speaker 1: of cars more efficient. Here's Professor Mardy allowed a dile monarking.
Speaker 1: So the idea is that you planned robot cars along traffic, right, yes,
Speaker 1: and somehow they're able to make things better. Can you
Speaker 1: explain that idea a little more.
Speaker 3: Yeah, So this is what we actually do in my live.
Speaker 3: So we try to exploit vehicles of technology to get
Speaker 3: transportation better for everybody and not just for the owner
Speaker 3: of the self driving car. And so the idea is
Speaker 3: that when we're talking, for example, about phantom traffic jams there,
Speaker 3: it happens because we get distracted. So if we instead
Speaker 3: of we assum and getting distructed, we have a self
Speaker 3: driving car, that self driving car doesn't get distracted and
Speaker 3: so doesn't have to slightly tap on the brake. And
Speaker 3: this is in the extreme case where everybody has a
Speaker 3: self driving car, but even the mixed case where we
Speaker 3: have I don't know, five percent self driving cars and
Speaker 3: ninety five percent humans, we can insert those self crime
Speaker 3: car or smart cars anyway in the midst of the humans,
Speaker 3: and what they would do is simply dissipate or smooth
Speaker 3: out traffic so that the disturbance caused by that slight
Speaker 3: up on the brake doesn't amplify it throughout the freeway.
Speaker 1: So then if there's a wave of breaking, having an
Speaker 1: automated car there to not break suddenly can fix it.
Speaker 4: Yeah.
Speaker 3: So the idea there is basically you look at the
Speaker 3: overall traffic. You estimate what would be the best speed
Speaker 3: for that amount of traffic for everybody to go, let's say,
Speaker 3: at a constant speed and not have any breakdown, not
Speaker 3: having any traffic jam. And then you tell this to
Speaker 3: whatever smart vehicle you have there, and basically the goal
Speaker 3: of that vehicle will try is to make sure that
Speaker 3: he does not overreact to what other people are doing.
Speaker 3: So he's not gonna catch up with the vehicle in
Speaker 3: front of it. His skin is gonna keep on going
Speaker 3: at that speed that the vehicle assumed to be the best.
Speaker 3: One kind of try and keep everybody at a constant speed.
Speaker 3: Oh I see, And so then all of a sudden,
Speaker 3: fifteen minutes later, you don't have anymore these huge traffic jams.
Speaker 3: And we did this both in close courts with one
Speaker 3: ab and twenty human drivers, but we did this also
Speaker 3: in freeway. So we had the largest ever experiment in
Speaker 3: which we had one hundred smart cars Floyd and rush hour.
Speaker 3: This was done in Tennessee on nine twenty four. And
Speaker 3: the idea was exactly that can we tell those one
Speaker 3: hundred vehicles to be like a pacer, like going the road,
Speaker 3: maintain a certain speed that we will give it given
Speaker 3: the current traffic condition, and see if they can smooth
Speaker 3: out traffic or at least avoid the creation.
Speaker 1: Of like plant some perfect drivers. Kind of yes, and
Speaker 1: it worked.
Speaker 3: Yeah, it showed that we can with a reasonable penetration rate.
Speaker 3: So then does need to be that big, so it
Speaker 3: can be like up to five percent. You can smooth
Speaker 3: out traffic. And the other thing that you can do,
Speaker 3: which is really cool, it's also reduced energy footprint of traffic.
Speaker 2: Because there's phantom traffic jams.
Speaker 3: What they do is you're currently accelerating and braking, so
Speaker 3: that is what caused the highest farce consumption on your
Speaker 3: vehicle or let's use an electric vehicle, so that caust
Speaker 3: also the highest pollution. And so if you smooth out traffic,
Speaker 3: you're able also to reduce this behavior and so reduce
Speaker 3: U summation caused by transportation.
Speaker 1: I see, well that's fascinating. So what would it take
Speaker 1: to do that, Like the city would have to buy
Speaker 1: some automated cars and for programming, or some people would
Speaker 1: have to volunteer too, like I want to be a
Speaker 1: pacer card.
Speaker 3: I think it's more the second, Like, I think you'll
Speaker 3: need to have some people that are willing to offer,
Speaker 3: like their vehicles, in.
Speaker 2: Order to do this.
Speaker 3: Oh yeah, there are different ways to do this. It
Speaker 3: can be incentive, or it can be simply volunteers, or
Speaker 3: it can be simply some good samaritan sides that they
Speaker 3: want to make life better for everybody else.
Speaker 1: Interesting, it's interesting that you can put robots to kind
Speaker 1: of guide people to behave better Be a car that
Speaker 1: doesn't make the common human mistake yes, overreacting.
Speaker 3: Yes, And also you don't want this car to we
Speaker 3: have two different than in humans, because otherwise, if you
Speaker 3: see some car in the road that behaves fundamentally different
Speaker 3: and how you would expect, then you get scared while
Speaker 3: you're driving, and then then it comes unsafe. So you
Speaker 3: want to have something that does this without the other
Speaker 3: human driving surrounding realizing that is doing this.
Speaker 1: I see.
Speaker 2: So that's the siddle thing to that.
Speaker 1: Okay, well that's fascinating. Okay, So that's one way to
Speaker 1: make traffic flow more efficiently and reduce uncertainty. You can
Speaker 1: have self driving cars sprinkled throughout that talk to each
Speaker 1: other and coordinate to basically hurt everyone along and not
Speaker 1: overreact or get distracted to break those phantom traffic waves.
Speaker 1: Another idea to improve traffic is to basically let computers
Speaker 1: take control of everything. Let's say a car breaks down
Speaker 1: in the middle of a freeway, or if there's a
Speaker 1: car accident that closes down the lane. A central AI
Speaker 1: could take real time data from traffic sensors on the
Speaker 1: road and predict what would be the best way to
Speaker 1: reduce the impact of that unexpected incident. Then that AI
Speaker 1: could tell people's Google Maps or ways where to go,
Speaker 1: and it could change the pattern of traffic lights at
Speaker 1: intersections to optimize flow of cars. Here's how traffic engineer
Speaker 1: Colin Mees puts it. Okay, so let me see if
Speaker 1: I can paint the perfect scenario here, Colin, So we
Speaker 1: have perfect knowledge of everything that's happening on the road, Like,
Speaker 1: first of all, we have historical data of like what
Speaker 1: the baseline congestion is going to be. We have perfect
Speaker 1: data of when accidents happen, and we can use that
Speaker 1: right away to predict the ripple effects of that event
Speaker 1: and then be able to coordinate with the apps people
Speaker 1: are using to divert them and change the traffic lights
Speaker 1: to accommodate those changes to ease that traffic.
Speaker 4: Yeah. I think that that was a great way to
Speaker 4: summarize the perfect scenario. That's really what we're working towards.
Speaker 4: And I hope that once these systems are you know,
Speaker 4: tested more and develop more, and we really have a
Speaker 4: reliable AI driven for example, system, then we can start
Speaker 4: seeing things like an AI agent changes the traffic light
Speaker 4: in response to the incident for us. I think we're
Speaker 4: pretty far away from an area where the AI would
Speaker 4: just fully be controlling the signal system, for example, without
Speaker 4: human interaction. But I think the AI can recommend things,
Speaker 4: simulate things, and then maybe a human says, yes, that
Speaker 4: looks good and will change the light dynamically to accommodate
Speaker 4: this for the next thirty minutes. And one thing I
Speaker 4: guess I will add to that that we didn't talk
Speaker 4: about would be just having better travel options too. So
Speaker 4: really improving the multimodal infrastructure in our nation is something
Speaker 4: that would go a long way. I know there's a
Speaker 4: lot of people that drive that don't even really want
Speaker 4: to drive, Like if they could take a reliable train
Speaker 4: from A to B every day instead of having to
Speaker 4: drive on the roads, then they would prefer to do that.
Speaker 4: If we think about investing more in alternate modes like
Speaker 4: we see in Europe, where the infrastructure exists and it's
Speaker 4: good and it's reliable and it's affordable, people will take
Speaker 4: those alternate modes, and that can also be another way
Speaker 4: that we can relieve some of the stress on the
Speaker 4: existing roadway system.
Speaker 1: I see, But then let me update my optimal optimal scenario.
Speaker 1: It seems like there's an optimal optimal optimal scenario, which
Speaker 1: is that people ride their bicycles and take the train more.
Speaker 4: Yeah, exactly.
Speaker 1: I mean not that sitting in traffic listening to say
Speaker 1: a science podcast is necessarily a.
Speaker 4: Bad No, definitely not. I think if you were sitting
Speaker 4: in traffic, that's probably one of the best ways you
Speaker 4: could be spending your time.
Speaker 1: There, you go. I feel like maybe traffic also points
Speaker 1: to a fundamental human need to come together to gather,
Speaker 1: Like if we didn't have that need and nobody wanted
Speaker 1: to ever align with anybody else's schedule, maybe there would
Speaker 1: be less traffic. But because you know, schools start at
Speaker 1: the same same time, work starts, the business day starts
Speaker 1: at the same time. Everyone wants to work together. We
Speaker 1: have that fundamental human need. Then that just naturally causes traffic.
Speaker 3: Yes, I think that's also part of the I wouldn't
Speaker 3: say a problem because it's not a problem like that.
Speaker 2: We want to be all together. This is part of
Speaker 2: just the situation as it is.
Speaker 3: And so I think it's just we need to be
Speaker 3: better at building public transits so that people will want
Speaker 3: to use public transit stuff taking the car or other
Speaker 3: sorts of transportation.
Speaker 1: Or maybe flying cars. I think that would solve everything.
Speaker 3: What do you think then we're gonna have congestion in
Speaker 3: the skies on the roads.
Speaker 1: But yes, works because of three D problem. Yes, yes,
Speaker 1: it's never gonna ends it.
Speaker 3: I don't know, Like I think it's gonna probably get
Speaker 3: batter us. We are getting better as time passes in theory.
Speaker 3: I hope it's gonna be a batter as time passes.
Speaker 1: All right, Well, if you're sitting in traffic right now
Speaker 1: listening to this, we really appreciate you spending your commute
Speaker 1: with us. I'm sure traffic will clear up for you.
Speaker 1: Pretty soon and hopefully it'll clear up for all of
Speaker 1: us in the future. Thanks for joining us, and hey,
Speaker 1: next week is the season finale of sign Stuff and
Speaker 1: it's going to be a pretty dramatic one, so be
Speaker 1: sure to tune in next week as we tackle one
Speaker 1: of the biggest signs questions facing us today, Isn't AI
Speaker 1: going to kills all? See you? Then you've been listening
Speaker 1: to Science Stuff, the production of iHeartRadio, written and produced
Speaker 1: by me or hitch Ham candidate by Rose Seguda, executive
Speaker 1: producer Jerry Rowland, and audio engineer and mixer Kasey Peckram,
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