Analysing Pedestrian Networks

As part of SYSTRA’s team at this year’s Transport Practitioners Meeting in Nottingham, Martin Parretti will be presenting an introduction to his ground breaking work on the analysis of pedestrian networks. Martin joined SYSTRA in August of 2016, after more than 10 years working as development lead at walkit.com.

Martin takes up the story, and introduces his TPM paper, which he will be presenting on the Wednesday afternoon of the two day event, as part of the ‘collective mobility’ stream:

“Working on ‘walkit’ enabled me to gain extensive experience with spatial network data, and in particular pedestrian network data – collecting it, transforming it and writing algorithms to exploit it. At the same time, I was thinking about all sorts of issues relating to walking around cities, and I had long wanted to explore and better understand how the structure of street networks in urban centres impacts on pedestrian movements.

At SYSTRA I have now started work towards a walkability model to help explore the reasons for bulk pedestrian movements in towns and cities. My first step towards this is an analysis of the walking network - how does the arrangement of streets and severances within networks encourage or frustrate movement along certain corridors?

Although network analysis and walkability are related fields currently undergoing active research, work towards a comprehensive model of why people walk where they do (or why they don’t walk in places they don’t) continues.

SYSTRA’s initial network analysis, which I will present at TPM2017, assesses the ‘betweenness centrality’ of links within the Birmingham City Centre pedestrian network. Such network analysis allows us to study the walking network independent of demand from push/pull factors, although ultimately a model of walkability will need to consider these push/pull factors as well as the quality of the walking environment.

‘Betweenness centrality’ calculations can help highlight a number of dynamics: lack of redundancy; the impact of severances; why certain roads and paths underperform as retail locations; or alternatively highlight potential targets for public realm interventions.

Birmingham provides an interesting case. Although great strides have been made to undo the damage to pedestrian movement of major city centre road schemes built in the late 1950s and through the 1960s, some major highways still exist in the city centre and carry high volumes of traffic through it. These roads continue to cause a severance, for example between the city core and some of the city centre’s outer quarters.

At TPM2017 I will show the visual results of our centrality calculations and discuss our qualitative conclusions.”