Transportation Planning
Overview
Transportation planning is the process of defining future policies, goals, investments, and designs to prepare for future needs to move people and goods to destinations. As practiced today, it is a collaborative process that incorporates the input of many stakeholders including various government agencies, the public and private businesses. Transportation planners apply a multi-modal and/or comprehensive approach to analyzing the wide range of alternatives and impacts on the transportation system to influence beneficial outcomes.
Transportation planning is also commonly referred to as transport planning internationally, and is involved with the evaluation, assessment, design and siting of transport facilities (generally streets, highways, bike lanes and public transport lines).
History
Transportation planning as a distinct discipline has evolved over the last century. The first urban transportation planners were often architects and engineers trying to solve the problems caused by cities built for horse-drawn vehicles, but with rapidly increasing automobile traffic. Early in the 20th century, many U.S. cities were growing rapidly and streetcar and interurban rail lines were being built. Sprawl was facilitated by the widespread use of streetcars and later automobiles.
In the post-World War II era, the role of the transportation planner was usually defined by traffic engineers who saw their job as the "optimization of traffic flow". The methods available to achieve this objective were limited to a narrow range of traffic management alternatives, such as traffic signals and highway capacity improvements. In the 1950s, as pressure mounted to address severe air pollution problems in cities, the job of transportation planners was broadened to take into account the environmental impacts of transportation decisions.
Methodology
Transportation planning involves a sequence of steps. The conventional transportation planning process is based on the rational model, where the basic sequence of steps includes:
1. Identification of problems or goals. 2. Generation of alternative plans or policies to address the problems or goals. 3. Evaluation of the alternatives in terms of their performance. 4. Implementation of the selected alternative.
This process is continuously repeated in a cycle as transport systems and the communities they serve are constantly changing.
Transportation Models
In transportation planning, the predictive models used were traditionally trip-based and rooted in the four-step model of trip generation, trip distribution, mode choice, and route assignment (collectively known as the "four step model"). More recent models are based on principles of microeconomics, and are termed "activity-based models". These models predict frequency and type of trips based on estimated activities that individuals and households will conduct at different times of the day.
Land Use and Transportation
The land use - transportation interaction can be seen as a distinct area within the transportation planning domain. It recognizes that transportation cannot be defined without a location and that transportation in turn affects land use. Many types of transportation planning are reactions to land use policies, and major land use changes require transportation planning. While land use planning often occurs to a large extent at local level, transportation planning is more systematic and analytical (rather than political and interest-based).
Sustainable Transportation Planning
Sustainable transportation planning focuses on the development of transportation strategies and solutions that minimize environmental, economic and social impacts. This approach to transportation planning is based on the principle of sustainability, which is the process of utilizing current resources in a way that will not compromise the ability of future generations to meet their own needs.