Jonas Tornberg

Urban economy as a scale-free network

We present empirical evidence that land values are scale free and introduce a network model that reproduces the observations. The network approach to urban modeling is based on the assumption that the market dynamics that generates land values can be represented as a growing scale-free network. Our results suggest that the network properties of trade between specialized activities cause land values, and likely also other observables such as population, to be power-law distributed. In addition to being an attractive avenue for further analytical inquiry, the network representation is also applicable to empirical data and is thereby attractive for predictive modeling.

Evaluating Locations for Intermodal Transport Terminals

Abstract The choice of location for an intermodal transport terminal is an important component in a regional logistics system and a paramount decision for the investor as well as the community affected. The investor needs a realistic estimation of traffic potentials and incorporated cost-estimates of a location, since it serves as an important input to the investment decision process. Policy makers need instruments and tools to analyse the effect of intermodal terminals on the surrounding environment, which also enables a comparison between several possible locations in order to ensure sustainability and long-term competitiveness. The model in this paper allows a comparative evaluation of a set of possible intermodal terminal locations based on considerations by relevant actors. Furthermore, it presents a process of retrieving data and effectively communicating results. Considerations and interests of stakeholders are incorporated into the approach by means of evaluative criteria. The approach aims at facilitating the planning process of regional logistics systems in general and the evaluation process of intermodal terminal locations in particular by considering both public and private interests focusing on economic and environmental aspects.

The CaSSandra Project: Computing Safe and EfficientRoutes with GIS

Large amounts of dangerous goods are kept constantly on the move in Europe because of their significant impact on economic growth and to support quality of life. According to available statistics [3], road transportation accounts for the movement of the major part of dangerous goods within Europe (58% in 2002). The access to a well built and distributed road infrastructure gives higher exibility and door to door capabilities [7]. Consequently, transport purchasers perceive this transportation mode as highly effective and economically advantageous. However, the same factors stated above oblige material ows to travel through highly-populated areas or highly-traficed road segments. As a consequence the exposure of civilians to accident risks increases drastically [3]. History shows that accidents which take place during the transportation of hazardous material can have the same magnitude as those occurring in industrial plants [13]. Possible consequences may include fatality of human beings or ecological disaster if the cargo is dispersed in water catchment areas [8],[6]. The ramifications on private stakeholders may include delayed shipment, undelivered shipment, wasted cargo and higher transportation costs (i.e. bridge collapse) [8],[2]. Dangerous goods or hazardous materials (hazmat) are any solid, liquid or gas substances that can have harmful effects for living organisms, property or environment [11]. Laws and regulations for the transportation of dangerous goods in Europe are first collected by the United Na tions Economic Commission for Europe, UNECE and then extended to all transportation means (road, rail, sea and air) through specific organizations. The transportation of dangerous goods over European roads is regulated by the Agreement concerning the International Carriage of Dangerous Goods by Roads (ADR) that is enforced in Sweden by the Swedish Rescue Services Agency (SRSA)[11]. The SRSA publishes yearly dangerous goods recommended and restricted road segments. Recommended roads are classified as primary, for throughway traffic and secondary, for local transportation from and to the primary network. The restricted roads are road tunnels and segments in proximity of water catchment areas [10].