Interacting Transport Systems - A New Focus for Transport Modelling?

Red bus Southampton

Transport planning, and the transport modelling industry in particular, can be quite inward-looking and segmented. Modellers class themselves as working in highway, pedestrian or public transport modelling. The standard outputs of a study are tightly focused. You model the highways, and report which junctions are over capacity and how good the travel times are.

You model rail lines and report the ridership, or comment on the efficiency of the rail system. The role of a transport modeller doesn’t really consider anything else outside your prime study remit.

Thus, it’s very rare to see more than one transport system properly assessed in a single model, but is it time for that to change?

The last few years has seen a distinct change in the way that people travel, and the coming years promise more major developments. A huge rise in the popularity of cycling and walking in our town and city centres has changed the nature of many of our roads, and one of the real hot topics nowadays is how to combine pedestrians, cyclists and high speed road users safely and efficiently. There is so much talk about new types of vehicle (autonomous vehicles, China’s Transit Elevated Bus to name but a few) and one of the keys to their success will be how they react and interact with other vehicles, people and the infrastructure around them. 

Sustainable cities and place-led development is becoming more prominent in urban planning, and it is obvious to see the impact that good public spaces have on the attractiveness of a city and the happiness of the people within it. The modelling of people within these places, and the routes they might take to access them, will be key to make sure that they integrate seamlessly into their cities.

The capabilities already exist for much of this modelling. Below are screenshots of a VISWalk model (VISSIM plus its VISWalk module) of Colmore Row in Birmingham. Watch our YouTube video (1m 14 secs) which demonstrates the model in action.

In this model, vehicles and pedestrians interact with each other allowing an integrated operational assessment of both vehicles and pedestrians. To explain why this is important, the travel time of a pedestrian depends upon how long they spend waiting for vehicles to clear a junction, and the delay to vehicles at a junction will often depend on how many times a pedestrian crossing is called. An integrated model like this allows behaviours like these to be included in detail. This results in more accurate model forecasts than you would get from separate models, and also gives a powerful visualisation of how the study area might function in the future.

The changing focus of transport planning, and the need to include additional types of vehicles in our assessments undoubtedly lends itself to a more integrated modelling solution. Could models like this become the norm in the future?