[MUSIC] Hello everyone, my name is Milos, and I'm just a simple Transport Engineer. And today, I will try to reflect a little bit on this paradigm of transport engineering, that we have established in the 20th century and are seem to be taking forward with us in the 21st century. The key idea here being is, if we're going to change, Our understanding, we need to dig deeper, yeah? So basically, talking about desired behavioral change in our mobility systems that needs to be achieved. But first and foremost, we need to understand the limits of our current thinking for this. As a kind of a framework for my own reflection and learning, I take these three aspects of individual expert learning, that our thinking is connected to a language, and that's also connected to our identity. And these are some things that might eventually come, must have on a table for our own discussions. As an example of kind of language questions and how they affect our thinking and identity, I oftentimes when I discuss in transport engineering courses with our students. Oftentimes pose this kind of question, so what is the difference between traffic, transport, and mobility? Oftentimes, some languages don't recognize the difference between some of these words. Oftentimes, they are kind of used in different kinds of context and connotations, following words are planning management and so on. But what do they actually mean, I will leave this to you, to think about, it might be an interesting conversation starter for you and your colleagues and friends. But greater question of course than this one is, what is to be a transport engineer? This is a question of identity as well. And I myself have of course been pondering that for some time, and this has led me to kind of try to think about different aspects, and learn more and more. Not just about kind of the state of the art in research, but where did we begin and where are we now, historically speaking? So, Aside from, some people they will tell you of course that, Roman emperors were transport engineers planning roads and so on. If we talk about sort of the professional as it is, the roads are some are in the 19th century and early 20th century. So we have these people like William Phelps Eno, who writes this rules of the road for New York City in 1909. Before that we have this recently rediscovered gem of the 19th century on the measurement of the utility of Public Works. That sort of establishes certain economic principles for thinking about public utilities and their planning and design. So, these people have been sort of emerging engineers in this field. They have considered themselves engineers, and they have tried to innovate different kinds of things and bring different kinds of ideas to the table that they might considered useful at that point in time, given information they had. But in fact, if we talk about sort of established engineering education and later on profession, it's only after the, World War II where we start to have solidified discipline. It was emerging before, especially in the period between the World War II. But eventually, after the World War II, it sort of becomes a combination of a set of disciplines. Civil engineering, the classical civil engineering and that was sort of, of course, on its own response to some military engineering in the past, especially in the US. Operations research that has proven especially important during war in the World War II, and then of course also neoclassical economics. That point in time provided, synergetic ideas to these other disciplines. So, given the fact that the roots of the discipline where at some point not so long, history relatively speaking. And that we had these disciplines in finding each other's knowledge compatible enough, where did this lead us, yeah? So, it'll lead us to these kinds of assumptions behind these kinds of questions. I will not try to unpack, but basically, the question were, what is to be a mobile human? What is a mobility system? What is the decision objective that we should have when we are supposed to shape this, this mobility system? So, these different disciplines brought to the table at that point in time certain kinds of knowledge, and that is still here with us as a kind of a dominant paradigm of the 20th century transport engineering. So, let's try to unpack them a little bit as we go forward. So, well, our kind of understanding of human being, human being on the move in an urban area, in the city is something some people refer to as home economics, yeah. The economic human, what does that actually mean? Well, we oftentimes talk about travel as derived demand. If you read a lot of classical texts in transport engineering, you will see this statement, yeah? Travel is derived demand. As shortly put as a definition, demand for a factor of production or intermediate good. That occurs as a result of the demand for another intermediate or final good. So, your demand is some kind of a function of price of goods, first your income and then this human aspect of tastes. As it goes, oftentimes another fundamental concept in this model of home economics is they have generalized costs. Yeah. Did your grandma have some kind of a weight at some. Adjusted for risk for comfort. The way that some of time spent on traveling or activity, other kinds of expenses. And other kinds of sort of costs that you can kind of monetize. The ultimate idea that have been that you are trying to measure things in a uniform way using money as a kind of a unified indicator of measurement. And then we can see this kind of generalized gentlemen cost. Example below formulas you have price on one side and you have added other aspects. You have time, some summations of different kinds of times time waiting for a bus time in a bus. Time walking from a bus to the train time in a train. Time walking from the train to your final destination. And then we can of course add other other kinds of factors, discomfort, and so on. And the idea there being is that well travel is trade off generalized cost. Have some kinds of activities versus some other kinds of activities. That kind of there is some something about decision making there. Yeah. How people make decisions as well and to other connecting concepts that we will now unpack one of them being utility function. They're very closely connected to this generalized cost. They eventually tell us something about demand overall. But we'll we'll get to that as well. Soon enough but there is this kind of, you know, marginal utility idea or diminishing marginal utility, that as you increase the quantity of a good. Well, the utility doesn't necessarily increase. Simply put, if I gave you one apple, we would have some kind of utility out of that if I gave two apples we would have well, I guess a bit more utility. But how much utility you will have, relatively speaking more as opposed to the levels as opposed to if I gave you sort of 50 apples I guess you wouldn't be. Just talk we wouldn't be just kind of, trying to understand the human in that way if we kind of focused on diminishing marginal utility. We of course also have the connection between the generalized cost and the demand that this cost is effectively. Supposed to tell us something about the changes in the overall demands, yeah? But we'll get to that as one of the underlying other pillars of our current thinking. But beyond the concept of utility is not just that kind of how do we measure this utility but the fact that humans are supposed to be in utility maximizers that you are kind of evaluating, comparatively evaluating between. Two or more alternatives, but usually kind of comparing them is based on certain kinds of goals and objectives that you have, that you're able to rank these alternatives that you have preferences that stable over time. And that this decision making is rational. And quotes means that it has this kind of completeness and transitivity axioms are there. Sort of, it's a certain definition of what, what rational human decisions actually are. And how do we oftentimes of course, measure this or kind of try to understand this human. Well we try to kind of dissect the travelling experience into different kinds of trips. So we have trip based data collection, we ask origin destination of trips, mode, chosen, route, purpose, other kinds of indicators, economic indicators. There was some kind of price associated with that or, other kinds of, properties off the, respondent yeah. So, that's a bit of that. The second part there was how to understand our money the systems. So if the previous idea of kind of home economics draws largely from from neoclassical economics. This aggregated system understanding is something that is rooted in origin ideas of civil engineering. Ideas, such as management of water flows. Or other kinds of engineering problems that have been there in the past. So data aggregation is usually or sort of aggregation of measures is usually how we try to understand our mobility systems. And we already took a glance at that when we talked about generalized cost exactly because this is is also something very strongly there in neoclassical economics, thinking that we try to have some kinds of aggregate curves that show us how the demand and the supply function given some kind of a cost, assumptions there. And again, we're going to talk about generalized cost in this in this context, as well and of course, behind this is some kind of an idea of an equilibrium as steady state equilibrium that, again economics as a discipline. Brought to the table at that point in time. This will lead us later on to some other fundamental points that have connected very well with operations research as a sort of originally, mathematical discipline. Well, discipline finding its roots in mathematics. I'm curious one of these other aspects or other examples of, of aggregate understanding of aggravation of origins and destinations. This is a classic. Super old, in a sense, figure. That's kind of show us how we think about origins and destinations and trips spread around space. So, you of course don't just talk about trips in their properties we also try to understand them in space. And often times we use also graphs like this. We really are. In fact even nowadays as we speak. We offer those focused on on modal split modal share share of transport modes in a city. That's something we automatically always aim to. And to follow over yours as well. It gives us an interesting understanding of system level performance. We of course, also try to look beyond trips into traffic, traffic volumes is one of these classical indicators. That of course derives from waterfall volumes and so on. Trying to kind of understand okay, what are volumes we have per day, or annually, or hourly slowly over space over time as well and we always have this spatial and temporal distribution of of traffic. Volumes. So those were some aspects, but let's dive also now into the third set of questions here, which is about, how do we actually decide what kind of objective functions we will use as engineers. And here we already see a glimpse, so we kind of do tend to use straightforward objective functions despite the fact that sometimes at first glance they look complicated. So, going back into the roots of transport engineering research, and later on education, this is one of those classic principles by personal wardrop from. Are the [INAUDIBLE] So the two principles of user equilibrium, the system optimum. They, we can sort of see there their definitions here. The one of user equilibrium being that, well journey times in all routes are equal that somehow by kind of. Rebalancing volumes. And throttling times people have rebalance volumes on the transport network so that eventually everyone has equal Equal travel times for well, a set of origin destination pairs. On the other side kind of spectrum we have the principle of system optimum where the volumes are assigned in such a way that. The total travel time is minimized. Yeah, when you sum up the total time before the people traveling between the given origin destination there. You end up minimizing their your total travel time. And that's exactly the kind of one of these important, very oftentimes used objective functions, looking more to the system optimum Approach. Usually, one would tell Obama consider that the system optimum approaches is better in a sense than the user equilibrium and thus we should try to minimize the total travel time trips total travel cost overall as well, yeah. But it also helps us in formulating this relationship between travel time travel cost and sort of what actually happens physically in time and space regarding our dynamic mobility systems that of course, also, have a lot of changes in volumes and other kinds of properties of system that I mix over time and space. And just to kind of give you an example of my own even. In this case, well, if you want to sort of solve a problem, you've set up a formulation. Don't let these indicators sort of scare you or confuse you. They're fairly straightforward. The first one is What are you trying to kind of what is the objective function so called? Yeah, you're trying to minimize total costs, in this case, monetary costs, roll time cost and so on. Your that's your kind of the objective function and usually have constraints. And these are just some examples of constraints. Oftentimes. They are in different kinds of optimizations, they are different, but this is the case of winter maintenance and sort of how do you sort of solve this problem of winter maintenance in a city or in an area? Where do you assign kind of, cleaning of routes and, and other kinds of things. And in this case, constraints are fairly realistic. You assign a vehicle to a route and eventually those route goals have to be attached to some kind of a depot, the point the node from where the routing is going to start. Yeah. At the end of the day. I think this is sort of a useful, useful example in kind of showing us that we have fairly straightforward objective functions and, rather, also straightforward constraints and these kinds of minimization approach or formulation of these objective functions, in connection to the previous aspects of home economics and are good aggregation. Are fairly obvious in two main tools used in, in transfer planning, which is on one side travel demand modeling, usually this kind of four step based modeling approach, a classical one and then that's usually kind of closely connected to cost benefit appraisal methods, where we try to sort of classify different kinds of, cost and benefits. Again, seeking to have them in a uniform way, over Euro dollar, some kind of a monetary monetary unit. So they are kind of again solidifying further the transport engineering thinking Language and eventually identity of what is it to do planning, yeah? Regarding transport. So, my time today was to just briefly reflect on this as a transport engineer, myself, to kind of unpack a little bit of these fundamental assumptions. So basically, what do we have? In the 20th century paradigm. Well, we have this sort of, interconnected loop of formulating humans as certain kinds of humans calm economic human. With rationality, with sort of maximizing utility, with kind of rationality that I said that sort of, okay, being able to distinguish alternative.. Alternatives to doll or all our alternatives, and to be able to, of course also understand the generalized cost. And then that feeds of course, into how we try to understand transport systems. And this has been useful. Of course you have this kind of aggregate understanding of transport systems. Give us an important, picture. The question of course, is the Is it a full picture, that will be something to discuss further on. But then of course, this is closely connected to these ideas stemming from operations research. Oftentimes have these kinds of straightforward to position functions, such as minimizing travel time, minimizing cost minimizing delaying stops, maximizing throughput, maximizing volume, you can have also that kind of objective function. But after all, there are still fairly straightforward, some kind of minimization or maximization. Formulation. So, you know, in, in a whole, you know total, these different aspects feed feed into each other they're fairly complimentary and they form they have formed and they're still forming largely the dominant paradigm how we. How we think about transport problems and solutions in urban, domain, how we talk about them and eventually what do we think? Transport and. Engineer is. I will leave you with that, and I will hope that we will have a lot more chances in this course to rethink some of these aspects and especially go back to the question of, well, what is to be a transport engineer? So from one transport engineer to the others, other people involved in transport systems. I thank you for your attention. And I hope this was able to open up some of the underlying assumptions and encourage your further thinking and learning
