(Unedited) Podcast Transcript 487: Killed by a Traffic Engineer

June 12, 2024

This week we’re joined by Wes Marshall, Civil Engineering Professor at the University of Colorado at Denver to talk about his book Killed by a Traffic Engineer: Shattering the Delusion that Science Underlies our Transportation System. We chat about writing process, the ideas of risk and exposure, and what he learned from pouring over old transportation engineering journals.

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Below is a full AI generated unedited transcript:


Jeff Wood: Wes Marshall. Welcome to the Talking Headways podcast.

Wes Marshall: Thanks Jeff. Good to see you.

Jeff Wood: Good to see you too. Before we get started, can you tell us a little bit about yourself?

Wes Marshall: Sure, I think I might go into a quick tangent here because I, one of the things I love about your podcast is, you know, oftentimes you ask these very simple questions like, and tell us about yourself or it’s like, how’s the weather? And people go on like a 20 minute [00:02:00] monologue, but the best thing about is at the end.

You are always ready with a question right after and you kind of get right back into it. So

Jeff Wood: that might be a function of editing too, to a certain extent. But, um, yeah, I try to, you know, put it together so that we’re telling a story or, you know, trying to help people understand the topic or get people to buy a book.

Right. So hopefully that’s helpful and I’m glad you’re a listener. I appreciate you listening. I mean, we met a while ago at TRB. We can’t remember what year it was, but it was at a Yukon after party of some sort. And I’ve known Norm for a long time, so he always invites me to the parties. And so we met and it was great to chat with you.

And so I’ve appreciated that ever since.

Wes Marshall: Yeah. And I think we ended up talking a lot more, one of the poster sessions. So, uh, that’s when I heard more about all the stuff that you’re doing. So,

Jeff Wood: yeah, which may be too much sometimes, but, um, but yeah,

Wes Marshall: so

Jeff Wood: let’s hear about you, what do you,

Wes Marshall: I’m trying not to spend 20 minutes answering this question.

So, Wes Marshall, I’m a professor of civil engineering at the University of Colorado, Denver, [00:03:00] I have a joint appointment in urban planning. I’m director of our human centered transportation program. That’s the gist of it. I’ve been working here at CU Denver for the last 15 years. Before that, I was a PhD student.

And before that, I was a consultant. So I’m a professional engineer in transportation engineering. So I’ve been doing this work for, I guess, 25 years now.

Jeff Wood: And what brought you to this? Or actually I should ask, when did this interest start? Was it when you were a kid or was it when you got older?

Wes Marshall: No, because when I was a kid, this stuff didn’t really bother me.

I grew up in Watertown, Massachusetts. So it’s one of those little cities that touches Boston right on the west side. And I grew up in a place where we had overhead wires, like our buses had catenaries that led us to Harvard Square and stuff. And I actually heard last week that they are removing those and switching to a different kind of bus system.

So that’s a little bit. Sad on that end, but it wasn’t until like, I did go to college. I was a civil engineer. I was at the time a little bit more focused on structural thinking might become an architect or [00:04:00] something in that vein. I wasn’t completely sure. So I figured I’d work for a little bit first to kind of figure things out.

So I went back to work and um, You know, soon thereafter, I ended up moving someplace else and that was the 1st time I lived in a place where I couldn’t leave the street I lived on without being in a car and it just drove me crazy. So, when I started thinking about the work I was doing, I was doing all sorts of stuff within civil, but it was always the transportation element of those projects that I was doing.

Never was as good as the stuff I saw in and around me in Boston and in Watertown and places like that. And I just kept curiosity. Like, why? Like, why do we do this? Why do we need as much parking? Why does the street need to be this wide? So that. Is what I started getting interested in so eventually that just led going back to get my master’s and PhD in this field.

So that is sort of how it grew. And, um, I think oftentimes people have that origin story. Like you start in a good place, move to a bad place or vice versa.

Jeff Wood: Yeah, and then I just tickled me, [00:05:00] but I was wondering how you met Jamaican Dumbledore.

Wes Marshall: Um, so I was living in Connecticut and I was looking to go back to grad school and Norman Garrick is who you’re referring to there.

He was a professor, University of Connecticut, and my wife and I were about to have our 1st kid. So 1 of the things that was important in grad school is honestly health care. Like having good health insurance and UConn had tremendous health insurance, probably even better than the health insurance I have now as a professor.

So that ended up being the only school I applied to and then looking at the application, you had to kind of check a box for which advisor you wanted. So I remember looking at Norman’s website and looking at the other professor’s website and I was like, I kind of like this guy, um, something about him. So I checked that box and, you know, I come to find out later how important.

Your advisor is for a PhD is way more important than the school and I just lucked out. I mean, I found like, for me, it was the perfect person for what I wanted to [00:06:00] do. And it was a lot of luck and just simply me liking his website a little bit more than the others and checking that box.

Jeff Wood: I think it’s really important too, because I know for me, the mentors I’ve had have been really important and kind of pushing me along this path, whether it’s like Hank Dittmar or Shelly Petitia or folks like that, it’s just been really helpful to have these mentors that kind of, you know, guide your way.

And obviously Norm was part of the CNU gang that I met a long time ago, but it’s interesting to think of you going in and putting on a sorting hat with Gryffindor on it. Uh, that’s actually a transportation hat, but I think that’s, that’s important to the journey. Right.

Wes Marshall: It is so important. I, I think people sort of underestimate that.

I mean, yeah, everything you end up doing, like starts with sort of how you think about transportation and he helped me think about it in the way i, I do now and just sort of learning and understanding. Like the first project I was put on as a grad student, like he was off. I think he was actually in Jamaica on a sabbatical, so I was sort of by myself there, and he put me in a [00:07:00] parking project, and, you know, when you first go back to grad school, you’re thinking, ah, parking, that’s not really that exciting, and this was before Donald Shoup came out with high cost of free parking.

So, during that time, Norman directed me to Donald Shoup’s research, so I read all his papers while Norman was off on a sabbatical. He came back, I’m like, oh my god, like, this is way more important than I ever realized, like, this is so fundamental to sort of everything we’re thinking about. And it was just a great start, but I don’t think you would ever get that in any other civil engineering program, any other civil engineering professor, so it was amazing in a lot of ways.

Jeff Wood: It’s pretty cool that you got Don Shoup to do a blurb on the back of the book, too. I was impressed by the kind words.

Wes Marshall: Oh, yeah, they were fantastic. And I was sort of against even asking people for blurbs. I felt like I was, you know, putting people in a tough position and maybe didn’t like the book. My original draft, before I even talked to Island Press, I had a lot of, [00:08:00] like, fake quotes from my friends and family, like, my kids joking, and, like, my friends saying they’re gonna get disbarred and stuff, um, I thought it’d be fine to just kind of use those, like, no, no, you might as well ask, you know, people like Donald Shoup, you know, who I know from having done this research back then, like, that’s sort of when we met, so, um, And then they came back with the most, I mean, just amazing.

I mean, I think I actually wrote them. Thank you letters last night for that, but they were just amazing. So I’m happy. I ended up getting pushed into doing that and getting that feedback.

Jeff Wood: Well, the book is killed by a traffic engineer, shattering the delusion that science underlies our transportation system.

Before we get into this, some of them are serious stuff. I do want to say like your footnotes aren’t really typical of most of the books that I’ve read, especially transportation books. And they’re all, not all of them, but a lot of them are hilarious Pop culture references that I personally got. So I figured you must’ve grown up at the same time as me and watched all the same movies I did and all that stuff.

So I appreciated that as part of the kind of bringing together a serious topic with some [00:09:00] pretty entertaining anecdotes and stories from pop culture.

Wes Marshall: Yeah. And that’s sort of the feedback I’ve been getting so far as people seem to love those. I mean, I guess nobody would reach out to tell me they hated them, but at the same time, I’m literally writing about kids dying on the road.

So yeah. Yeah. It would be a tough, tough read if I didn’t, you know, try to add some levity in my personality to it. I mean, I also wanted to make it different than all my academic writing. I have all these academic papers, and to do something different felt like this was the time and place for it.

Jeff Wood: Yeah, Billy Madison, Tommy Boy, Talladega Nights, uh, all kinds of fun stuff in there.

Wes Marshall: They’re not random. They are random.

Jeff Wood: No, they’re not random at all. They definitely relate to the subject matter, but it’s just like, okay, watching that movie 30 times actually came in handy when I was reading this book.

Wes Marshall: Yeah, I had to fight a little bit like to get those in the final draft and You know, I kept getting comments from the copy editors like, is this necessary?

I was like, well, is anything necessary? Like, can’t we have a little fun too? And I, I [00:10:00] fought for enough of them that it kept the gist of what I was after from the beginning.

Jeff Wood: Well, so I want to get also into the underlying basic themes of the book. There are 88 chapters in the book and they’re not long chapters.

Wes Marshall: I start off with the idea, talking about doctors and medicine, so doctors have been around for 5, 000 years, for the first 1, 000 you could probably argue pretty well that doctors might have killed more people than they saved. Traffic engineers, traffic engineering have been around for maybe a hundred, a little bit over that, and I’m trying to say we’re still in that stage.

It’s not our fault because we’re doing what we’ve been taught, we’re doing what’s in our manuals. At the same time, a lot of the crashes and deaths we’re seeing, it’s a systematic thing. So at the same time, it needs to be an empirical science like medicine in order for us to fix things. So that [00:11:00] was the bigger picture theme is trying to understand sort of why we’re still killing so many people.

Like we think of it as this science that is so well developed, but My question was, is it? And that allowed me to dive down all these rabbit holes to see why we do this, why we do this, what the engineers were thinking at the time we came up with these different methods that we use today. And what you end up seeing is sometimes when you get to the bottom of the rabbit hole, you’re like, Oh, really?

That’s why we do it.

Jeff Wood: And this hasn’t been done before. I mean, it seems like nobody’s really gone back and looked at this much detail and going back into the research and looking back in the history to see where some of this stuff came from and why it’s still persistent. Yeah.

Wes Marshall: Yeah, I think when I first thought of this book, it’s like, oh, I can just point out all that we do wrong.

I was like, well, that isn’t quite enough. Like, I need to understand why. And I mean, that’s why I relied so much on a lot of the older papers, like 30s, because I wanted to hear it in like their voice, you know, trying to almost open up the curtain and see the person behind it to see what they were [00:12:00] thinking.

And a lot of times you just see, hey, like they were clearly admitting that we don’t know enough yet. We’re going to try this for the time being, but then like 10 or 20 years later with the rest of us forgot that was the case that it was still something that was up in the air, and we sort of just moved on and treated it as a given and like time and time again, you saw sort of stories like that.

You’re like, Oh, really? Like, that’s. That’s the original research paper as to why we do X, Y, or Z, and you’re like, holy cow, that’s, that’s crazy, and I mean, that speaks to, you know, even though despite the title, I don’t think it’s Traffic Engineer’s fault for this, like, it is just the way things have perpetuated through time that led us to this point, and how that’s gone, that it’s easy to sort of forget, like, the details of those original papers.

Jeff Wood: The one that pops in my mind right now is like doing a reaction time study with older folks that are in their 50s, but only having a couple of them compared to like a lot of younger people and like the sample sizes are crazy.

Wes Marshall: Yeah, they’re talking like [00:13:00] 15 total people, like their definition of an older person was What’s it like 50 or something we wouldn’t even,

Jeff Wood: we’re getting there ourselves.

Wes Marshall: And even the way they did it, like, you know, they threw something in the middle of the road and let people drive around and they sort of asked them when they saw that thing in the road or the other one with a gun, where they shot a gun off under the car to see like when people reacted to something in front of them.

Like. You know, they’re perfectly fine studies for the time, but we should have kept going and kept trying to understand the differences and if there were differences, but instead we just said, Oh, look, we have a study that says that the same reaction time for old people, young people, like, that makes it easier for us.

Let’s just proceed like this. And we don’t really go back and see if that is true or we forget the original details of that study. And yeah, I mean, it’s become problematic over time.

Jeff Wood: I’m interested also in like how many traffic quarterly papers you went through to try to get the nuggets that you felt were the most important or [00:14:00] interesting.

Wes Marshall: Oh, oh, it was way too many. Um, yeah, there was, I want to say dark periods, but I felt like, you know, I was asking myself, am I crazy? Like I literally had a thousand pages of notes. That I had, you know, I printed them out all those papers. I organized them and then I ended up reading Robert Carroll’s book working.

You ever read that one? He sort of talks about a process.

Jeff Wood: No, but I’ve heard about it secondhand.

Wes Marshall: So he wrote the power broker and Linda Johnson’s books and. It made me feel better. Like I’m not crazy. Hadn’t done what I did. So my thousand pages of notes, I’ll be okay. Like, cause he went way beyond, like he moved to Texas and lived there for like a year plus just so people would talk to him for like an hour.

Like, so the amount of research he was doing was sort of well beyond. So it made me feel better. So, I mean, in the end there was a couple thousand of those traffic quarterly papers. And I, you know, You know, I ranked them in terms of what would be definitely useful, potentially [00:15:00] useful, and then I ended up kind of going through each tier of those, the ones that were sort of safety focused and the other ones that looked interesting.

And I just literally took notes on all of them and ended up with this Again, a thousand pages of notes that was for me, it was a giant puzzle in my next job. I spent six months just trying to figure out the pieces of that puzzle and trying to organize things. So that was kind of my process,

Jeff Wood: you know, I mentioned Jamaican Dumbledore, but thinking about J. K. Rowling and whatever her opinions are on public life and things like that now are a little bit frustrating for some folks, but her process was really interesting. I mean, she’d had everything laid out for the first book, the second book in these big spreadsheets. And so I can see, like, Folks writing books and putting things like this detail on this axis and this detail on this axis to make sure they match up.

I imagine something like that was your go to.

Wes Marshall: Yes, exactly. And because I also read Stephen King’s book called On Writing where he talks about his process and he just literally sits down and starts writing like he has an idea. And he just goes for it. I’m like, Oh, my God, like, what am I doing? Because I read his first [00:16:00] before I read Robert Caro’s.

So that is also, I don’t know if anyone else reads those kind of books like I do, but it got me really to think about, like, the actual writing and, you know, just removing things like adverbs. Like, so there’s a lot of great details in there. And that’s an interesting book too, because half the book is literally on the writing aspect.

But then he had a crash, I think while he was biking in Maine and he was really hurt, almost died. And so the rest of it is almost like a memoir about that crash and his alcoholism. So it was, I suggest that book. It’s off topic for a lot of what we’re talking about, but it’s interesting.

Jeff Wood: I feel like all of these things are connected in some form or fashion and transportation.

We, Tend to silo things, right? That’s one of the ideas in the book is like, we’re so specialized and that’s something that we maybe overdue. You have this interesting quote from Andres 20 about, you know, specialization and Raymond Unwin, who, you know, one of our things is we did an audio book, Raymond Unwin’s town planning and practice.

So I was appreciated that I saw that in there. Um, but yeah, just like thinking about the specialization that we go [00:17:00] through, especially for traffic engineers and cutting it off from everything else.

Wes Marshall: Yeah, I kind of went a little bit of the opposite direction in that because you hear that we’re too siloed like that.

It’s a problem that we’re just stuck in our silo. That’s all we can sort of think about. And what I’m trying to show in that chapter is we don’t even teach our traffic engineers enough to have a silo. Like, even though I told you my process of, you know, sort of how we got to transportation. I got a civil engineering degree.

I got my professional engineering license in transportation. Like, that was my depth section. And at that time, I had taken 1 transportation engineering class total. It wasn’t until I went back to grad school that I figured out I knew nothing and that I was just starting fresh. But a lot of people. Spend their whole career having taken 1 or even 0 transportation courses, like the way our accreditation works.

You don’t actually have to have transportation engineering courses to get a civil engineering degree, but those students are still eligible to become professionally licensed [00:18:00] transportation engineers. So, and that sort of leads into some bigger picture things about. You know, why we’re sort of so tied to our thousand page guidebooks is because we haven’t taught our engineers enough to think beyond them.

Like I’m just handed these books as a young engineer and the best I can do is just follow what they say. And it’s hard to have any bigger picture engineering judgment beyond that.

Jeff Wood: And that was one of the ideas that you kind of hammered a couple of times in the book was just this idea that, well, first off, you’re pretty sympathetic to traffic engineers generally.

I thought that was pretty interesting, but also like the amount of classes that people take in school to get to be a traffic engineer. It kind of shocked me actually, when I was reading through what you were writing.

Wes Marshall: Yeah, it is shocking and I think that’s part of the problem. And another part of the problem is the classes they are taking are like the structural engineering classes and the hydrology classes and the mindset with all those courses is factor of safety.

Bigger is better makes perfect sense. When we have a beam for a building, if it’s bigger might cost us a little bit more, but, [00:19:00] you know, it’ll be safer. Right? Mother nature is not going to change. What she does based on the size of our beam, but with transportation, that same mentality, like everything we’re taught, if we make a road bigger, yes, it might be safer.

People behave the exact same way, but you know, people were human, like we behave differently depending on what you put in front of us. So if you make the road wider and people drive faster, that’s why you get Counterintuitive results, and that’s part of the reason why I think we’ve been floundering a little bit and making our road safer is because we have these theories that make sense based on the factor of safety mindset, but the reality does that when you add humans to the mix,

Jeff Wood: there’s human errors and engineering or police led data collection errors that lead to human errors and driving and humans are always going to do stupid stuff, right?

Like, I feel like there’s a lot of things you can’t engineer out, but you can do more than we are doing now. Yeah.

Wes Marshall: Well, part of the bigger problem is that we just blame all the crashes on the humans. Like, yes, humans do stupid stuff, but if I, like, we’re just talking about a wider road, if that wider [00:20:00] road is enticing people to go faster, enticing people to speed, like me just throwing up a 30 mile an hour speed limit sign, it’s not enough.

But our data will tell us that the problem We need to focus on enforcement or education. I would argue that it’s really an engineering problem, but our data has let us, you know, we all want a data driven safety approach, but the data is all telling us that it’s an education and enforcement problem. But a lot of it is systematic.

Like, we know what happens when we design a road like this. We know, you know, if everybody in the road is speeding, is that really an error? Is that really a mistake? To me? No, like, it just lets engineers off the hook from designing a road. That is self enforcing, that entices the right behaviors that we’re looking for that lead to safety.

Jeff Wood: One of the biggest themes in the book might be about exposure. And, you know, that goes to some of the measurement issues. But what is exposure? And how is our data story not really any better than what they came up with in the 1930s? Or maybe it’s something that was created to [00:21:00] do something specific.

Wes Marshall: Exposure is basically the denominator in our crash rate. So we take, you know, the number of fatalities or injuries or just total crashes. You don’t want to really just compare the raw numbers. So we want to put them on an apples to apples and a more level playing field. So you want a denominator that oftentimes has, you know, Over the last 100 years, just been vehicle miles traveled for the most part.

So if you have 13 fatalities per 1 million miles, like we can compare things on a more level playing field. But at the same time, when you think about those metrics, like when the denominator is vehicle miles traveled, there’s two ways to get better safety. One is we reduce fatalities, injuries, or crashes, right?

We reduce the numerator. The other way is to increase the denominator. Like if we increase VMT, we can all seem safer. And when you actually think about what this means for neighborhoods or for people, and which is I go through that early in the book, it doesn’t. Make any logical sense whatsoever. It leads us [00:22:00] to solutions that nobody would choose.

Like, I compared two towns, Heresville and Driveton, and I asked people, where would you rather live? Like, who would you rather be? Like, if you and I are getting to work today, and you drive a hundred miles and get into five crashes, and I drive ten miles and get into one crash. Who would you rather be? Like, the answer is clearly me, right?

I had one crash, but our safety metrics would say that you were doubly safe than me, because you’re only having one crash every 20 miles. I was having one crash every 10 miles. So, from a human standpoint, you’re like, what the heck? Like, this makes no sense. All our metrics are driving us towards more driving, but if you thought about it, Like a human health impact, because I argue that, I mean, dying on the road is bad for your health.

If we treat it like anything else we do in human health, where the denominator is population based, like per 100, 000 residents, you often get the exact opposite answer. And that’s part of the reason why I think we’ve been [00:23:00] pushing in the wrong direction, because we’re just measuring the wrong thing.

Jeff Wood: You found that dense places were safer and some of the research, I remember that you all did the research looking at like the smaller cycling towns in California.

Wes Marshall: Yeah. That was, that was all my, like my dissertation. That was you. Yeah So that was all me.

Jeff Wood: So, you know, all that stuff comes to light. And it’s interesting that, you know, someone like Jane Jacobs basically says the same thing is like, look at all those older places that are working. And so why shouldn’t we replicate those rather than create some crazy formula to make something new up that might not work as well.

Wes Marshall: Yeah, but if you look at the way we measured safety, like if we focus on fender benders, just total crashes, you can see like those places might have more fender benders, but way fewer people are dying on those roads. But if we’re focused on the fender benders, you look at that place is unsafe, right? But if you look at it from just any person that’s using that street, it’s safer.

So we’re doing sort of the opposite of what is common sense in a lot of cases. And that’s sort of one of them. And that’s what we found with some of that street network research, like the gridded street networks, the ones that were more [00:24:00] compact. We’re yeah, I think we had 7 to 9 percent more fender benders, but those same places were killing, like, 3 times fewer people than the more tree like networks.

So, yes, you feel like you’re safe if you move to this cul de sac, but the type of big arterials we have to use to support those sort of street network designs, like, those places are killing way more people than the other places. But, like, the way we were measuring safety, there’s a lot more driving there, so it just seems safer.

Jeff Wood: We had David Eder and Kerry Watkins on to talk about the safe systems pyramid and talk about the idea of kinetic energy, which you mentioned briefly in the book. There’s references to this in book as well as research approach of William Haddon. But I’m also interested in your kind of like the deeper thoughts you have on, you mentioned it just a second ago, but I want to know kind of the deeper thoughts you have on a public health approach versus like an engineering specific approach.

Wes Marshall: With the engineering specific approach, folks, is more on the facility. Like, if we have X number of miles driven on it, we can look at safety [00:25:00] for that facility. But the more public health one looks at the population living there. I actually had a dentist appointment this morning, and I had to go maybe a mile and a half to get there, right?

If somebody else had to go, let’s say, Mhm. 10 or 20 miles to their dentist appointment. Like, they’d be contributing more safety to the system if neither of us get into a crash. But again, who would you rather be? Like, it makes much more sense because I have much less exposure and I’m going a much shorter distance to get to my dentist, but the way we’re measuring everything from kind of the facility standpoint, the traffic engineering mindset, the other person Is contributing more safety to the system, but if you think about it again, more on the population level, it seems so obvious, but it, but we’ve been doing this for 100 years.

Like, this started in like, 1937, 1939, like, those initial times we shifted to this measuring safety metric that we’re still using today.

Jeff Wood: Studebaker’s Paul Hoffman. Is [00:26:00] that right? Yeah. And then they were the originators of the Texas Transportation Institute as well. One of my old foils. And so I appreciate that connection as well.

Wes Marshall: Yeah, he made the right point that we need an exposure metric, but he just picked the 1 he liked best and the 1 that would help cars seem safer into the foreseeable future. He wrote a book about it. He went around the country teaching this new metric to a burgeoning new traffic engineering discipline.

We bought into it. 15, 20 years later, it was codified into the Federal Highway Act, right? And we’ve been using it ever since.

Jeff Wood: Another theme of the book seems to be like this crutch of math and numbers, whether we’re calculating life costs, you know, how much crashes or different impacts cost. I’m wondering, why do we try to math everything?

Wes Marshall: I think we do it to keep the engineers above the fray, right? If we just put numbers to it, it’s easier. Like, if we say a life is worth X number of dollars, and we sort of count how many people die in this road, then it’s a simple cost benefit analysis to see if [00:27:00] what we were planning to do for an intervention is sort of worth it.

Even though I don’t think it really does keep us above the fray, like, we are making value judgments and moral judgments by even putting numbers to those things in the first place, and like some of the examples I give, like now when we do the same thing, a life is valued, you know, over 10 million dollars, but back in the 1950s, 60s, 70s, it was more like 300, 000, and then we value just any old crash for one tenth or one twentieth of that, so, The way we did the math, we would say, well, it’s worse to have 25 just fender benders than to have someone dying.

We do put the same thing with like congestion costs, like sitting in traffic, sitting in, this goes back to your TTI, you know, we put numbers to that. Like how much is it. Actually cost people to sit in traffic and we say, well, your value of time is, you know, 20 an hour. If you sat in traffic for half an hour, that’s like 10 bucks.

We have, you know, 100, 000 people on this road every [00:28:00] day. This happens over the course of the year, over 20 years. Like this adds up to billions of dollars. But when we actually do the math, you would say that we’re better off solving the traffic problem than saving lives. Like it, it doesn’t really add up when you do it.

And it’s not like I’m going to make any more money if I And sitting in a little bit less traffic, like, a couple minutes less every day. Right? That’s not real money. And that’s not real money that, like, D. O. T. gets when they want to build a new road either. So, it’s not even a fair comparison, but, you know, it lets us just simplify things in a way where we’re kind of taken out of.

Having to make a decision, like we’re just letting the numbers make the decision for us, even though we’ve created the system that’s created those numbers that has led to that decision.

Jeff Wood: I was chatting with a friend yesterday who was also reading the book and his biggest question was why are engineers so defensive?

And I thought that was an interesting one coming at it from your perspective.

Wes Marshall: Yeah, I think that to some extent goes back to the lack of [00:29:00] education that we’re giving them. Like, it’s hard, we don’t teach them enough for them to really think through a lot of the stuff. So, their mindset is like, I just have to follow these guidelines.

If I don’t, I’m liable. It’s hard for them to see the bigger picture sometimes, because this is the tools they’ve been given. Like, this is what they’ve been taught. And the theories that I’m, you know, I’m going through a lot of the theories and I’m showing a lot of times that, you know, What we’re doing today is based more on theory than the empirical results, like, I think we have to shift more back to empirical science, but when your mindset is like, oh, this, you know, a wider street is safer, like, we’ve been told that for 100 years, even though the new data will say that’s not true, like, that idea is perpetuated, and sometimes it helps.

And I feel like this is the case when, um, you know, you’re trying to talk about a conspiracy theory and show, you know, that it’s not true. I mean, this isn’t quite at the same level, but the idea that water roads are safer, when I found those original [00:30:00] studies, they were comparing 18, 20, 22, 24 foot roads.

Like the widest road they looked at was 24 feet wide, which is way narrower than any road we’d ever built today. So yes, in that original study, 24 is safer than 18. Sure. Extrapolate that to 60, 80, 100. Does that mean it’s safer? Well, no, but you know, 10, 20 years later, we forget the details of the original study, but that idea has perpetuated that our wider roads are safer.

So we have these, all these theories and that’s what all these Guidebooks are telling us and all those guidebooks, we assume are steeped in safety research, but it’s not to the extent that, you know, when I was a young engineer, I assumed that whoever wrote these books knew more than I did. But now that I got a chance to really dig into it, they clearly admitted that they didn’t, like, they said, we don’t know the answer here.

This is what we’re going to do for now. So that is sort of. The big vicious cycle we’re caught up in.

Jeff Wood: Has anybody gone and taken a look at [00:31:00] the green book or any of these guides and said like, okay, let’s go in back and do all these studies over again and see like which ones still work and which ones don’t.

Wes Marshall: Over time, we’ve removed the citations to those original studies. So I had to go through like the older versions of all those books. And you see sometimes like the first couple of versions of the green book, they would cite that paper on the Road width and safety, and then you see, you know, 1957, like, all of a sudden it’s still there.

The next version in 73, they’ve actually removed the citation and they’ve just kind of kept the sentence saying that this leads to better safety. So that is kind of the problem. It’s hard to even know what the original study is. Like, I had to Literally go down a bunch of weird rabbit holes to find them

Jeff Wood: when you sit down and talk with engineers, and there’s an anecdote in the book about this.

When you talked with someone in Denver, you disagree with them. And I’m wondering how those conversations go.

Wes Marshall: I will say over time that it’s getting better. Like there are [00:32:00] some traffic engineers that are turned off by the title. And what I’m trying to say is, Hey, if you read it, I think you’ll agree with me.

Like, if you can kind of get past the title part. So I’ll. A lot of them now that is even though it doesn’t officially come out till next week. A lot of people have somehow got it in their hands and they’re already reading it. I’m getting great feedback from engineers and it seems like they’re craving more information like this.

Like they know there’s something wrong, but they don’t really know what. So hopefully this can point them in the right direction. So, you know, that person that I’m talking about in that story has retired and now there’s 2 people. That are craving this sort of information in his place and you can see the results in the streets.

Like, we’re changing the way a lot of cities are looking and it’s partially because of that.

Jeff Wood: I have an interesting theory. I want to share with you that maybe you’ll agree with or maybe you won’t cars and roadways are designed to lower insurance costs. Right? But we induce more driving because of the way that we built our built environment.

So it actually maybe does the opposite. Yeah. You create more VMT, you create more opportunities for [00:33:00] crashes. You increase insurance rates and now cars are getting more expensive and heavier, which means they’re more dangerous, which means they’re more expensive to repair. Rinse, repeat insurance costs, increase inflation, increase.

I think there’s like a cycle here that continues and it’s kind of based on this idea that we’re trying to save the car, you know, from crashes.

Wes Marshall: Yeah, and all our cars are designed, I mean, the way bumpers are designed, they’re not designed to help pedestrians or bicyclists. Like, they’re designed to reduce the more expensive damages you might have to a car.

I mean, that is what we’ve been focused on. And, you know, the bigger picture thing you’re suggesting with the VMT, like, that plays into it. Like, you know, but if everyone was biking to work like I did today, like, maybe they wouldn’t need the same cars and insurance. So that would Put them out of business to some extent, so they don’t want that either.

Jeff Wood: Recently, Scott Wiener introduced legislation here in California to add speed limiting, uh, warnings, basically 10 miles an hour over, and you get a warning from your car. And I’ve seen a lot of the comments on it, and it seems very divisive and [00:34:00] very frustrating. I found that kind of interesting when I was reading your book too, and thinking about all of the ways that people push back on, you know, the idea that they might be limited by some sort of regulation or some sort of safety measure.

Wes Marshall: For whatever reason, a lot of common sense stuff like that is, seems just un American, right? And it feels like it isn’t quite to the level of like the gun debate, but it doesn’t feel that far off. Like, the idea that, oh, you’re going to pull the steering wheel out of my cold dead hands, isn’t that different than like what we would argue for the guns.

For whatever reason, it ends up being arguments about things like freedom instead of arguments about safety. It quickly devolves away from safety and that’s. You know, when you look at other countries, I was in Australia on sabbatical back in 2017, and they do a lot of the stuff that we wish we could do, but their argument is safety.

Like, we’re doing this to make people safer and saving lives, and here, you know, simple things like red light cameras become big brothers watching us, like all this other stuff, and no one is talking about the [00:35:00] safety. We’re talking about whether it’s a cash grab by the government, and you’re talking about all the stuff that is completely tertiary to the intent of what we should be focused on.

Jeff Wood: Speaking of guns, apparently you carry a radar gun.

Wes Marshall: I do. I got a, it’s right here. The little one.

Jeff Wood: So how do you use that when you’re out in the, I mean, is this for research purposes or are you just interested in how fast cars are driving or what’s the,

Wes Marshall: Um, yeah, I mean, sometimes it helps to put a number with what you’re seeing.

So a lot of times if I just take a picture of a street, it gives one impression. But if I, I’m holding my radar gun up with my left hand and you see a car going like 73 on a 30 mile an hour street. I take that picture. It’s a completely different impact in terms of a picture. So, you know, I don’t sit there and I’m not taking like 1000 speed thing.

I’ve done that in the past for different research projects. But when you are taking that number of speeds, you often do it a different way. But this sort of gives you a sense of what is happening because it is a little bit hard to gauge how fast cars are actually going unless you kind of [00:36:00] pull out the radar gun and see for yourself.

Jeff Wood: Another theme might be the transportation theory of everything. There’s a housing theory of everything now that’s basically posits that housing is the base of some of the major ills that we have, not just housing, but maybe jobs, connections, things like that. And then one of the other things that struck me from this book specifically was this transportation theory of everything.

You fix safety and you get free range kids. And one of the things that I appreciated from Melissa and Chris Bruntlett’s book was that, you know, basically they were saying like, As soon as we got to the Netherlands, when they moved there, they had more free time because their kids had more ability to go places.

So they didn’t have to show for them everywhere. So you get more kid freedom, you get more parent freedom. And I feel like there’s a lot of value there. And that kind of comes from basically that transportation theory of everything.

Wes Marshall: I just got back from CNU, so the Congress for the New Urbanism in Cincinnati last week.

And one of the things I’ve long kind of joked about is that the dirty little secret is that new urbanism is really a transportation movement, or more specifically, it’s a transportation land use movement. A lot [00:37:00] of times it gets pigeonholed as an architecture movement, like front porches, like that sort of stuff.

But the difference between the places that work and don’t work comes down to transportation. Like, if you get the transportation right The architecture can be so so and it is fine. If the architecture is great and you get the transcription wrong, the place just doesn’t work. So that facilitates so much, I mean, like you suggested, and I think we underestimate that.

We sort of focus on other stuff.

Jeff Wood: That’s another interesting thing that was part of your book too, was like this land use connection that was made a long time ago at one of the, you know, conferences. And I would just finished Michael Batty’s book as well, the computable city. And, you know, basically Alan Voorhees had suggested in the modeling with early computers, they are trying to do all this transportation modeling.

And he was like, why, why are we not talking about land use too? What’s the deal. And I feel like sometimes those things, you know, obviously they’re connected to us and folks who are listening to this podcast probably feel that way as well. But for a lot of folks, it’s just like the transportation and then you have land use and they’re separate.

But I think that connecting them [00:38:00] is very important.

Wes Marshall: And I think we have known that for a hundred years. Just, we haven’t been doing that. Like the way our models work, we sort of assume the land use is separate. Like we look at projections for population and employment and we see where, you know, given current trends, where those might end up.

And then we try to model how many cars are going to be needed to serve that population and employment. And we just try to accommodate that. So. It simplifies the problem, but it’s just predicting in providing like, we’re not actually coming up with a vision for a region and trying to head in that direction.

You know, over time, we’ve moved more towards scenario planning where we do this sort of thing. But, you know, as you know, you got to cut up and. You know, zoning regulations from different municipalities and the states are trying to do something different. So it’s been a little bit hard to coordinate that, but they go hand in hand.

It’s hard to look at one without the other, but we rarely do so.

Jeff Wood: I also feel like you’ve made a similar argument that [00:39:00] Jared Walker makes, which is like geometry is a constant. And, you know, the things that we can change are things that we knew about, you know, a hundred years ago, like you said, like a hundred, 200 years ago.

And even before that, when we built cities for walking. So I found that interesting as well as from a coming up with thinking of cities and there’s no new fancy technology that’s necessarily going to fix that. It’s just that there’s geometries that work in geometries that maybe don’t.

Wes Marshall: And it’s fundamental.

I mean, all the cities that have solved congestion have killed their cities. Like, it’s not a place anyone wants to be anymore. That’s the only way to solve congestion is to make your city a place that no one wants to go to. A little bit of congestion is a good thing and cities need to embrace that and use that at the same time.

Yeah, I think there’s always people selling, like, new geometry, so to speak. Like, so right now Elon Musk is selling the underground boring tunnels, right? It’s the same thing as Futurama from that we’ve had over the years. It’s just what I joke in the book is the Stranger [00:40:00] Things version. It’s just upside down, but it still runs into the same fundamental geometry problems.

Like, you still have to get cars up to the Futurama elevated highways. Or down to those tunnels and you have the same like geometric constraints that you have that you do when a highway enters a city like at that interchange, like, that’s where you get the congestion. And that’s where you get the backups and you’re going to have the same problems.

It doesn’t solve anything. It’s something we’ve tried and failed out before. It’s just underground now.

Jeff Wood: When I was reading the book, there was a number of times where I saw you were talking about something specific and you’re talking about the history of it, but then I didn’t see necessarily any like newer research about it, whether that’s the lane width study that just came out from Johns Hopkins or, um, you know, that we talked about the safe systems pyramid and things like that.

I’m wondering if that was like a conscious choice to like, not try to include every single study that kind of disproved all the things that you were talking about.

Wes Marshall: To some extent it was, I mean, originally my first draft was instead of 88 chapters, it was 100 and it was 160, 000 words and [00:41:00] longer than Prisoner of Azkaban.

Jeff Wood: Big book.

Wes Marshall: But to get that published, like, oh, we need to cut it down to like 130, 000 words. And at the same time, I wanted to make the book more fundamental. Like, Actually, one of the things I learned when I kind of came out of my cave and I started reading all the transcription books that I missed was how quickly a lot of them seem dated, like ones that came out like in 2020 or 21.

When I was reading them at the end of 23, a lot of the stuff felt old already, like when you talk about a specific newer study, like even newer ones have come out, so I wanted the book to hold up better over time and also entice people to do more research on this stuff, like one study Like from Johns Hopkins is great, but we need more on that sort of stuff.

And that is sort of my bigger picture thinking on that.

Jeff Wood: Yeah. No, I appreciate that. I also appreciate that you had like, you know, Tara Goddard’s work in there as well, media framing and that type of stuff. Cause I think that’s interesting new research too. That kind of goes to the points that you make as well.[00:42:00]

At the end of the book, you made me tear up a little bit. And part of the reason why is because we recently had a very sad tragedy here in San Francisco, where a whole family was killed by a driver at West portal, which is a major trans station. And for me with a two year old, uh, I, I saw myself in those.

People because they were going to the zoo and I could have been there in that, that space. And so a lot of the times that you teach classes, you say that you tell real stories about people and the real folks that have been impacted by traffic violence from being, getting killed by cars, getting run over, mostly kids.

And so I’m wondering like your grief and your pain is growing and. Do you think each of these, you know, each of these gets harder as you get older, as you mentioned, like, do you think that there’s a, an end to that kind of suffering you create for yourself when you tell these stories?

Wes Marshall: It’s hard to even think about something.

I get, it does, it makes me tear up a little even thinking about some of those, those stories that you can tell, and the example you just gave. I’m so sad, but yeah, I mean, the point I’m trying to [00:43:00] make, like, everyone’s saying, Oh, we kill, 40, 000 plus people every year. Oh, there’s whatever the numbers are. Like, they’re still just numbers like, and it’s numbers that engineers will look at on a spreadsheet and we don’t really pay much attention to like, we treat them as the cost of doing business almost.

And every night you can turn on the news wherever you are, and they’re going to talk about someone that died on the roads. And it’s like a faucet just dripping and nobody really notices it. Okay. Until you put a name to it, until you put a face to it, until you talk about the families that have suffered and are still suffering, um, it just changes people’s perspective on the problem so quickly, and I don’t want to use these people just for that, but a lot of them have said, you know, if I die On the roads, like when I bike home tonight, like, please use my death to, since I changed, like a lot of people want to see this change happen.

So it feels like the right thing to do to kind of keep these [00:44:00] names alive and show that we did a disservice to them and we could have done better.

Jeff Wood: I’m sure you’ve had a lot of discussions about the book since you finished writing it. Um, obviously it’s not quite out yet, but it will be soon when this is released, I’m sure it’ll be out, but I’m wondering if there’s a question that you wish people would ask you.

Wes Marshall: Hmm, that’s that’s an interesting question. You know, I, I think it’s maybe the, just like some of the bigger picture stuff, like, I mean, I use we a lot as I write because I am a transportation engineer. I’m a professional engineer myself. I’m trying to include myself in that. And I think to some extent, like, something like that helps or that chapter on level of service.

I talk about that original meeting that they were having, or they’re deciding like, A, B, C, D, E, F, like that sort of thing. And, yeah. You know, I say, oh, you know, a guy named Charles from New Jersey says this, and this guy from California said that. So that’s why they added A. That’s why they added F. And, you know, the copy editor wanted to give their full [00:45:00] name and their description.

I was like, I want to get people feeling of how that meeting is. Is like when you’re in it, like all the times, you know, that’s Charles from New Jersey. You don’t really know, but that’s how it feels like. Oh, Charles said that we want something better than the best. We need like an a instead of just to be like, that’s how those meetings are and feel.

So I wanted to put people in that. So, I mean, that is why I’m using like, 1st names a lot with people like Paul Hoffman, like, put you on a 1st name basis with him and try to, you know, Put us a little bit in the time of what they were thinking there. So it’s those bigger picture questions that I think hopefully the book is more effective like this way, but that is sort of what I’m going for.

And, you know, I think it’s hard to see when you’re just kind of reading it, but there’s sort of bigger stuff that I think will hopefully help.

Jeff Wood: I do appreciate that. There was a guy named Mr. Capacity.

Wes Marshall: Yes. Okay. Norman.

Jeff Wood: That was what people called him. Mr.

Wes Marshall: Capacity. Yeah. And he got a gold watch when he came up with level of [00:46:00] service.

Then he died like a few months later. And that was,

Jeff Wood: that’s crazy. That, that whole, that whole thing is crazy. Obviously I’ve paid close attention to that and here in California, as we do with SB 743, but it still doesn’t get any easier. So going back to kind of pop culture, I mean, you end the book talking about Marie Kondo and given some of her background and categories, admittedly, I was thinking, you know, when I was reading out that, you know, she kind of gave up some of this stuff.

After she had a kid recently, there was a news report where it was like, she was like, you know what, maybe it’s harder to do this than I thought, because I have little ones running around now and make it almost impossible to keep clean. But by the end of the book, you use the condo categories to start addressing issues you bring up in the book.

You have kids, you have active transport, transit minus parking and building places to reduce exposure by reducing the need to make long trips. And so what brought you to the idea to pick one small item at a time, or maybe you pick Marie Kondo as your example to kind of, uh, spark joy.

Wes Marshall: So it felt like whenever we’re trying to fix safety problems, we’re just playing whack a mole, like we’re looking to see where we have the most crashes or the most [00:47:00] deaths or the most pedestrian crashes or bike, whatever it is, like we’re doing.

A little bit of intervention all over the place, and we’re not thinking about the bigger picture and how we’re seeing the same systematic problem across not just, you know, Denver, my city where I am, but all the cities like Boston and where you are and everywhere else. We have a much more fundamental problem happening.

And I think. You know, I think I remember watching her Netflix show where she does things based on categories, like, she makes you take all your clothes you own and put them together just so you get a feeling of the scale of the problem you’re dealing with. So, instead of just going room to room, like, instead of us just going intersection to intersection.

Let’s take a better look at the scale of the problem. Let’s look at like something bigger. And that was the general thinking is we need. Now I can point out all these like little things we can do to do better. But at the same time, we just need a fundamental rethinking [00:48:00] of what the problem we’re trying to solve is.

And that was my approach to that section is just trying to say, Let’s think about categories like kids, and those are just examples of categories we could use, like where do kids live? Where are kids going? Think about schools and parks. And if we can start with those categories and start making our places safer for kids, then they start becoming safer for everyone.

And that was the idea behind that. It’s a much more bigger picture, more systematic way to think about these problems.

Jeff Wood: Have you gotten any like negative reactions to the book aside from the title? I mean, obviously that’s, that’s been kind of tough, but like, folks that actually maybe read it or read a couple chapters.

Wes Marshall: Um, not from anyone that’s read it, like, the only negative reactions I’m getting so far, like, like, Hey, man, like, don’t blame me. Like, we’re doing the best. It’s like, yeah, I mean, that’s, that’s the only. Negative ones I’ve seen so far, but I mean, maybe I’m just in my bubble and no one, I’m not on social media and stuff.

So I don’t maybe see a lot of the comments [00:49:00] that, uh, you might otherwise. So, um, yeah, it is what it is. I’m happy with the book. So that’s where, yeah. If

Jeff Wood: you’re happy with it, then that’s good, right? I’m

Wes Marshall: happy with it. People that have read it, my friends, like people like you that kind of the early people that have seen it seem to be happy with it.

So I feel like, you know, I, I did what I set out to do.

Jeff Wood: Well, for me, I feel like I need to buy a hundred copies and start throwing it at people, right? Like I, I, I’ve already thought of like a bunch of people that I just want to throw it at, not in a negative way, like hit them or anything. Just be like, here, have this book, read it, get back to me, uh, after you’ve read it and tell me what you think.

I, I just, it’s interesting. I had a conversation with a, a longtime friend, a high school friend recently, and they have a different opinion than I do on traffic safety. And, uh, I just kind of want to send them this book and be like, Hey, look, This is what I’m talking about when I talk about this. Yeah,

Wes Marshall: that’s good to hear.

Yeah. I’ve heard of the folks that want to send like a copy through all their city counselors and stuff, but I don’t know. It’s a 400 page book. So it was hard to get, [00:50:00]

Jeff Wood: but it’s important. I think like if I was going to suggest reading any 400 page book, this might be the one that’s the most important one to read because there are so many little details and there’s so many little items in here that I feel like would change people’s mind and not just like individually, but cumulatively it makes a big impact.

So I appreciate that as well.

Wes Marshall: When I tried to write it in a way where, you know, I have, like you said, 88 sort of short chapters, and my goal was each one of those has sort of a beginning, middle, and end. And then I separate them into 12 parts. So even each section sort of has a beginning, middle, and end. So fundamentally, it’s just these short stories were Even though I dug into a thousand traffic quarterly papers from the thirties, forties, fifties, sixties, it’s not a history book, as I think you can vouch for, like, I’m trying to use those stories to kind of shed light on what is going wrong today.

Jeff Wood: You know, I think about, I think it’s like a little bit of a transportation pattern language, right? 88 different interventions you can do to make a better transportation system, right?

Wes Marshall: Well, hopefully, uh, People are still using it [00:51:00] like 10 or 20 years from now. I mean, that, that was sort of my goal is something that is going to last and stand the test of time and maybe help make some changes.

Jeff Wood: The book is killed by a traffic engineer, shattering the delusion that science underlies our transportation system. Where can folks get a copy if they wish to get one? They should, they should go right away and pick it up. They

Wes Marshall: can get it anywhere that they shop for books. So I’ve heard of. People going to their local bookseller and they can get informed, but it’s on the island press website.

It’s on Amazon. It’s on like Barnes and Nobles and all those sorts of places.

Jeff Wood: Awesome. Well, Wes, thanks for joining us. We really appreciate your time.

Wes Marshall: Awesome. This was fun, Jeff.



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