New Study Uses Accessibility to Measure Effectiveness of Public Transport in Rapidly-Growing Cities
November 24, 2011
BEIJING, November 24, 2011 - A new study - Wuhan Urban Accessibility Planning Support Systems - was recently completed by the World Bank, with the aim of helping city authorities understand the dynamics of urban development in relation to transport in a rapidly growing Chinese city using the concept of accessibility.
Accessibility is a fundamental measure of the benefits of urban life. In essence, it measures the end benefit of the integrated transportation and land use system: how many destinations (generally jobs but also shops, schools, entertainment, and recreation) can be accessed in a given time using a given mode of transport. Increasing accessibility – bringing people, opportunities and goods within easy reach of each other – has always been the fundamental role of cities.
In recent years, increasingly powerful spatial analysis tools (GIS) have become more prevalent – allowing for a more practical and fine grained analysis of these issues. Switching to a system of measuring accessibility offers an improved way to analyze these interactions, allowing for integrated analysis of the land use transport system. In concrete terms, accessibility analysis can help understand the implications of a new highway, a new transit system, or the relocation of a large employer from the downtown area to a city’s suburban fringes, all using the same tool and measured with the same metrics.
In the past, policy makers often analyzed the transport system using metrics that focused on mobility – the ease of movement in a city. The most prominent of these metrics is congestion, often expressed as the ratio of road speeds between congested and uncongested conditions. Unfortunately, using metrics that focus on travel speeds alone are excluding a crucial component of urban system dynamics.
In particular, these new tools can assess how, where, and when public transport systems provide a service that is competitive with automobiles. To help promote the use of these more energy efficient modes, accessibility tools allow the analysis of scenarios of both transport and land use change (for example, new zoning regulations or a new express bus service) that can address this spatial mismatch in a level of detail previously unavailable.
For the rapidly growing cities of the developing world (including but not limited to China, where this work was piloted), using accessibility measures to understand the role that land use and transport dynamics can have on the economic, social and environmental life of the city will be a powerful new tool. This study also goes one step further, using accessibility metrics in combination with a dynamic model of land use and transport that allows for the analysis of how current trends, policies, and plans will influence accessibility in future years.