Transportist: June 2022

Congratulations to Australia for a peaceful transfer of power and the lack of demagogues proclaiming “election fraud”. 

Towards Zero

Life is full of trade-offs.

When we conduct a business case (benefit/cost analysis), “ideally” we reduce decision making to a comparison of the monetised benefits and monetised costs. We say, e.g., the value of travel time savings is 40% of the average wage rate. If there are any safety impacts, we might note that a  value of a statistical life is $11,800,000 (for Americans, it is much less in other countries, despite the US’s penchant for devaluing life). If we are doing a better than average job, and considering environmental externalities, we price pollutants, and may even have a carbon tax. We say all this as if life or environmental damage can be substituted by money. When designing a transport system, we may choose to invest in one safety feature and not another, and instead spend the funds on something that reduces travel time. 

Of course, we don’t say your life can be substituted by money, your life is priceless (to you), but other people’s statistical lives are not, and as humans, we don’t act as if they are. But following through to its “logical” conclusion, if we assume the average price holds even as the number of people decreases, the lives of some 8,000,000,000 people on planet earth could be traded for (society would be willing to accept) $9.44e+16 in exchange, but who would be there to receive it? So while the average statistical value of (other people’s) life perhaps holds at the margin, it cannot hold for the whole.

We have similar values for pollutants, but clearly a sufficient amount of some pollutants (CO, NOx, SOx, Pb, PM10, PM2.5, O3, CO2) would kill us all. So while the trade-off price might be valid at the margin, it must increase to infinity as the amount of pollution increases. 

In the end, human life is a perfect complement to human transport. More humans begets more travel. If there were no life, there would be no human transport, and vice versa. These are consumed together. And if this is clearly true in the end for everyone, it is probably true at the margins as well. So perhaps we should not be monetising life and the damages caused by pollution, but instead looking at reducing crash risk and pollution in an absolute sense. But even if we took a Pareto Optimisation approach (no one is worse off, or in this case, no externality is exacerbated), there would still be trade-offs, we could still make more safety improvements or more travel time reductions.

Treating externalities in a non-monetary way requires multi-criteria decision-making. But typically that only abstracts the problem away from money, there is implicitly still a trade-off. 

Over the short-run, this trade-off might be necessary, when so much of the system design is fixed; but does it remain over the long run? A system that pollutes is wasting resources. A system that kills people is wasting resources. That can’t be efficient overall, we are just shifting the burden from a subsystem of all life to another subsystem. 

We often treat life and health and the environment as sacred values. We embue lost lives, and polluted environments with emotion and meaning. In contrast, we don’t treat lost time as sacred. If one were to posit “Zero Delay” in the same breath as Zero Deaths, one would be viewed as a crank. Instead, to those stuck in traffic we say you wasted time, ha-ha, we are not saddened by the thought of others in congestion. 

Nevertheless, unlike road deaths and air pollution, delay continues to remain a salient political issue, which we see in the sloganeering of “congestion busting”, and implicit in all traffic engineering decisions aiming for a better Level of Service. I would also argue that delay is largely unnecessary1

I posit that it is less expensive in the long run to design a transport system that doesn’t pollute, and doesn’t kill, injure, and maim people, and doesn’t result in needless delays, than one that does. A long-run, over-arching benefit-cost analysis would recognise and reward better long-run designs that resulted in zero externalities, following on the ideas of “Net Zero” and “Toward Zero Deaths” from transport, rather than expecting trade-offs of time for safety or time for emissions.

New Journal: Urban Informatics

Urban Informatics (UI) is an international, open-access, peer-reviewed journal publishing high-quality, original research on urban informatics, including urban system, theories, methods, and technologies for urban big data acquisition, infrastructure and analytics, as well as new solutions to urban problems and applications. 

Though published by Springer/Nature, the Article Processing Charges are waived for the first two years.

I am on the Editorial Advisory Board.


  • Zhao, X., Cui, M., & Levinson, D. (2022). Exploring temporal variability in travel patterns on public transit using big smart card data. Environment and Planning B: Urban Analytics and City Science [doi]








Futures Past



Recognising that journey delay (time wasted in-vehicle driving at speeds below “freeflow”) would have to be replaced by schedule delay (time spent at the trip origin waiting to travel later, or departing early than desired to avoid journey delay, and thus spending time at the destination you would prefer not to). We assume journey delay is worse than schedule delay because you have more flexibility at your origin and destination to pursue other activities than when sitting in traffic or on a train. This despite time being a fraction of life, and certainly we would rather typically be doing something else.