MOSART : an Innovative/A Prototype GIS-T for Planning Sustainable Mobility

Topic area D5

MOSART: an innovative GIS-T project for planning sustainable mobility

Aurélie MERCIER, Nicolas OVTRACHT, Yves CROZET Laboratoire d’Economie des Transports, France (CNRS, Université de Lyon, ENTPE)

Since the 1990s, in France like in many countries, urban transport policies have aimed to solve congestion problem developing an efficient public transport network at road network’s expense. In this context, issues of decreasing speeds and increasing densities impact not only individual and collective travel times but land-use planning. The concept of accessibility, associating both travel time and land-use components, is pertinent to forecast and to plan sustainable mobility. The GIS-T-based project “MOSART”1 has been implemented to improve sustainable mobility policies using modelling tools and simulating accessibility for different transport mode users (car users, public transport users, for example). This paper presents this innovative GIS-T examining first the GIS’s databases and methodology then illustrating its use with two applications. The paper can be considered by itself but is in fact combined to another one focusing on different transport policy scenarios using MOSART (see Crozet, and al., From GIS-T to urban transport policies: Accessibility simulations to favour sustainable mobility). MOSART is implemented, using VISUM software, on the Lyon Urban Area (LUA) and covers more than 1.2 million inhabitants spread over 514 km². Many databases, spatial or not, are integrated in the GIS-T. The LUA is divided into 296 districts consistent with spatial databases but accessibility simulations are made using a spatial division into micro-zones of 500 meters (1 640 feet) by 500 meters with their respective centroïds. Two different transport networks are introduced. The road network obtained from the database NAVTEQ is composed by more than 90,000 nodes and 220,000 links . The public transport network, with more than 1,000 kilometres (620 miles), is represented, in its urban part, by 5 subway-lines, 4 tram-lines and 135 bus lines with more than 2,300 stops generated. An interurban network with a regional rail network is composed by 10 railways lines. For each line, timetable has been integrated for a typical weekday schedule. Connections between two different modes (or public transport lines) are considered. MOSART incorporates socio-economic data from different sources (National Institute of Statistics, private companies, transport surveys etc.) and integrate them into GIS. Land-use is determined with various databases like Navteq land use layer, or National Geographical Institute with the BD Carto’s. In a second part, the paper presents two applications of the GIS-T. Analysing impacts of the transportation system on accessibility is one of the main “research fields” of MOSART. In a first version MOSART focus on “isochronal” access measures. To measure time-based accessibility, travel times are computed using a shortest path analysis based on a speed differentiation between links. For public transport an access time to the network, a connection time, and a waiting time are also integrated. Isochronal accessibility maps are of further interest as they are “intuitive” and illustrate evolution of area accessible under a time-constraint. Nevertheless these time-based measures have limits mainly because they don’t consider the ratio “number of opportunities/distance”. Therefore in a second version MOSART presents gravity- based access-measures. These measures depending both on transportation system and land use pattern, computations are implemented from relationships between spatial databases (with the number of jobs, of stores etc.) and travel time matrix between the each micro-zone. In this context the introduction of a four-step model to integrate congestion impacts on car-access levels represents a main improvement way for MOSART. New avenues of research can be suggested as introducing a web-mapping interface for different type of users (individuals, public decision- makers…) to visualize impact of transport policies on access levels.

1 The acronym MOSART can be translated by modelling and simulation of accessibility on networks and areas.