Many questions arise for the transportation-land use modeller with the prospect of autonomous vehicles. Its effect on urban form will be heavily influenced by the manner in which it is implemented. It is probable AV will become a ubiquitous replacement of our current auto fleet, but may not be placed under personal ownership. One alternative would be a public fleet of vehicles. This has the advantage of being controlled by a single entity with a history of managing shared mobility services. Given the rapid emergence of the technology and its beginning in the private sector via automobile and technology firms, it is also likely for AV to be implemented as a set of competing services, similar to Uber and Lyft. This has advantages from the perspective of competition leading to innovation, but raises equity concerns. In addition, by placing the means of transport into private hands, there are concerns raised about privatization of infrastructure, etc. The final alternative would be a simple replacement of private automobiles, with personal ownership of each AV. These alternative implementations have the potential to influence the impact of AV on urban form.

My thoughts on this matter are concentrated on representing these alternative implementations in an integrated modelling framework. Do existing model frameworks have the capacity to model such changes, or are new methods required? The LUTI modelling field developed within a relatively stable transport system (i.e. the private automobile paradym). There is likely a need for increased dynamics in models. Rather than examining the impacts on demand of the introduction of a new interchange, we are interested in the changes in urban form resulting from a change in transportation supply and associated changes in demand. Alan Wilson is one of the founders of spatial interaction models and continues to develop innovative ideas with regards to dynamics in urban systems and their basic form. One of th concepts he considers is the idea of an urban ‘DNA’ and introduction of concepts from biological evolution into urban modelling. These types of concepts are critical in the development of models with the ability to consider seemingly large deviations from our current systems of transport. This requires a concept of fundamental rules of urban formation and growth to be operationalized in the model and not allowing oneself to be constrained by current transportation modes, etc.

One of the structures attributed to the introduction of the private automobile is urban sprawl, but to the history nerd this form appears long before. Without dipping too deep into history, we can see similar forms in the country estates of 18th century Britain. The ‘London Season’ was a time of the year when these nobles and other wealthy property owners would come into the city for a time to meet and put together marriages. We seem to have a natural, in our DNA, preference for solitude and personal space. Conversely, we also require proximity for social engagement, even with our rapidly developing communication technologies. Increased wealth among the middle classes has brought the ability to own a small ‘estate’ within the grasps of the every man, suggesting urban sprawl is not only a function of the automobile, but an ingrained desire that became possible through increased wealth. In the context of AV, I wonder what ingrained, DNA-based, desires and preferences will manifest themselves in our urban form. I perceive a need for better longitudinal data analysis, rather than close calibration to data from the current year. Rather than forcing the spatial structures of today onto the model, we should focus on dynamics and long-term trends. I have more confidence in the stability of the human mind than a concrete overpass with a 50 year design life, built 40 years ago. We must look to analogy in the phyical sciences in physics and biological DNA, but remember we humans are complex and dynamic systems. We should also be considering the latest concepts in economics and psychology. Not allow ourselves to be pulled into the stream of past models, but let them guide us.