Understanding patterns of growth at Kendall Square using a system dynamics approach

Abstract

The interdependency of transportation investment and land use has yet to be fully understood to quantify the benefits of transit infrastructure. Researchers agree on the complex relationship of urban systems, particularly transport and land use, as they fail to take a holistic approach when addressing this issue. Traditional travel behavior models have a number of limitations, since they describe an equilibrium point, connecting the model inputs and outputs. In reality, however, we have to admit that there is a constant flux given the interconnected changes in transportation, landuse, and the associated policies. Public policies often fail to achieve their intended result because of the complexities of both the environment and the policy making process. It is argued that, in order to understand the sources of, and the solutions to, these issues, linear and mechanistic thinking must give way to non-linear, systems thinking. System Dynamics, a methodology that emerged in the 1960s with the work of Jay Forrester and his colleagues at the Massachusetts Institute of Technology (MIT), has been utilized in this thesis to address these complex issues. This System Dynamics approach simultaneously models land use and transportation systems in the Kendall Square area. The model is based on the causality functions and feedback loop structures between a large number of physical, socio-economic, and policy variables. This perspective confirms that a combination of job opportunities, employment density, accessibility, changes in mobility patterns, agglomeration of industries, and proximity to MIT has made Kendall Square a unique location in the Boston area. Hence the interest on identifying the specific dynamics and interactions that exist in the area, to examine the limits of growth. The System Dynamics model built consists of 4 sub-models: population, employment, housing, and travel demand. While this is a first attempt at using System Dynamics to model the interaction between transport and land use in Kendall Square, the model development and application are limited due to data availability and the research scope. However, the results indicate that the proposed method is a promising approach to deal with complex land use development and transportation. The model shows how a system's approach can yield accessible, insightful lessons for policy making, stemming from the endogenous and aggregate perspective of system dynamics modeling and simulation presented here.