Accessibility as a Metric for Mobility Management

By Marcos Paulo Schlickmann, Urban Mobility Consultant, OPT – Optimização e Planeamento de Transportes & Mobility Editor of Caos Planejado

Accessibility is a concept that can be defined as the number of destinations that someone can reach or access in a given period of time. These destinations can be jobs, health services, education, leisure, or shopping. In the book “Order Without Design”, Alain Bertaud emphasizes the importance of this concept, and presents practical ways to make it operational in the day-to-day management of mobility in urban areas. He considers that reducing travel times for all people in order to increase potential accessibility – especially to jobs – should be one of the main indicators of managing urban mobility.

Bertaud maintains that one of the greatest advantages of large metropolises for rural migrants was to offer a potential supply of jobs and, consequently, various services in a small territorial area – all which can be accessed in a relatively short amount of time. Although we associate traffic jams with big cities, it is still in these places where destinations are usually faster to reach when compared to rural and low-density areas.

Visualising accessibility in urban areas

One researcher conducting prominent work in this area is Professor David Levinson of the University of Sydney, founder of the “Accessibility Observatory”, a platform where maps and accessibility reports are produced for a variety of metropolitan areas.

Source: Caso Planejado
Source: Caso Planejado

On the maps shown above, we can see that in Miami, the potential accessibility to jobs in a private car is much greater than with public transport: in 30 minutes by car, an average worker can access more than 2,500,000 jobs, while on public transport, just about 250,000!

Operationalizing the concept of accessibility: urban planning vs. urban management

This uneven pattern of access to opportunities through transport is common to many cities. However, inequality in access is not limited to the means of transport, but also the location of origins and destinations. Cities with a greater mix of land use in their peripheries bring together more diverse origins and destinations. There will invariably be a concentration of jobs in the center, but if more leisure, health services, education, commerce and general services exist on the peripheries, accessibility levels will increase without the need for significant investments in transport infrastructure. For this, a possible option is to make the zoning laws and master plans more flexible, thus allowing a broader range of land use in a more balanced way throughout the municipal territory.

One of the arguments often raised is how city halls do not effectively measure the performance of master plans. As already mentioned, the incorporation of this metric in urban planning would imply changes at a strategic level, such as the relaxation of zoning laws, to allow densification and a mixture of use in the periphery. Central to these strategic changes would also be transport planning aimed at reducing average travel times for all users of the transport system (not just for private cars) and for all trip purposes (not just for commuting to work or school).

To paraphrase Enrique Peñalosa, Colombian politician and advocate of urban accessibility, the big difference between rich and poor is not noticeable in access to work, but to leisure. Overall, transportation systems are usually organized so that all users can get to work relatively quickly. But what about leisure at the end of the day or on weekends? A resident of a housing complex under the Brazilian Minha Casa, Minha Vida program has almost no access to leisure in a timely manner. Rather, leisure remains isolated in the home; children are not able to easily play in the street, so what’s left is television. In short, the mania of politicians to build large parks and gardens should be left out: they are expensive and encourage travel by car. They should build – and maintain! – small parks in neighborhoods.

‘Minha Casa Minha Vida’ housing program. Source: Palácio do Planalto/Isac Nóbrega.

In the context of urban management, accessibility can be monitored by travel times. Nowadays, with the abundant location information collected by big players such as Google, it is possible to monitor the travel times of the population on a daily basis. On this indicator, the local government can act to try to reduce these times, both through urban planning at the strategic level and through small changes to the road network at the operational level.

Two key indicators of accessibility

The path to operationalize this indicator is promising. In Brazil, IPEA is developing the “Project Access to Opportunities”, which aims to “understand the conditions of transportation and inequalities in access to opportunities in Brazilian cities.” The first results (2019) present data on the 20 largest cities in the country for public transport and active mobility modalities. Two indicators are recommended for destinations such as work, health, and education: Percentage of Accessible Opportunities and Minutes to the Nearest Opportunity.

Access map to opportunities in Recife. Source: Caso Planejado

Rafael Pereira, coordinator of this project, has extensive experience in this area. He also collaborated on the production of the “Transport Access Manual: A Guide for Measuring Connection between People and Places”, a guide that assists in quantifying and assessing accessibility and helps transport and urban planning professionals to get a more comprehensive view of their city or region. A recent example of the attempt to operationalize this concept comes from Paris. Mayor Anne Hidalgo has advanced with the idea of the “15-minute city”, which seeks to bring together origins and destinations within a 15-minute walk or cycle ride.

When David Levinson says that the city is an accessibility machine and the car is a mobility machine, he affirms that the city center is a place that usually allows someone to reach a range of destinations in a short period of time. This pattern of land occupation, combined with a good transport system, should be extended to other areas of the city, thereby reducing travel times and increasing access to opportunities for all citizens.

This article was orginally published in portuguese on Caos Planejado

Caos Planejado is a Brazilian digital platform for urbanism and cities.
Our multidisciplinary team of collaborators includes architects, urban planners, economists, traffic engineers, students, activists, real estate entrepreneurs, social entrepreneurs and journalists. We cover topics such as public space, mobility, housing and work, heritage, density, environment, academic theory and practical actions, from public policies to tactical urbanism.

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