American Institute of Certified Planners (AICP) Practice Exam

What analysis evaluates the relationship between the force of attraction and vehicular trip generation in transportation planning?

1. Regression Analysis

2. Gravity Model

3. Cost-Benefit Analysis

4. Traffic Demand Model

The correct answer is: Gravity Model

The Gravity Model is pivotal in transportation planning as it quantifies the relationship between trip generation and the attractiveness of destinations. In this context, the model operates on the principle that the number of trips generated between two areas is directly proportional to the attraction of the destinations (which can include factors like employment opportunities, schools, commercial areas) and inversely proportional to the distance separating them. This mimics the gravitational forces in physics, hence its name. The Gravity Model effectively captures how people are influenced by the size of a destination—larger destinations are typically more attractive and thus generate more trips, while increased travel distance generally results in fewer trips. By analyzing these relationships, planners can forecast traffic volumes and make informed decisions about infrastructure planning, land use, and transportation system improvements. While other analyses mentioned play important roles within transportation planning, they serve different purposes. Regression analysis focuses on assessing statistical relationships between variables without necessarily adhering to a spatial model, cost-benefit analysis evaluates the economic viability of projects, and traffic demand models project future traffic volumes based on various parameters but may not specifically emphasize the attraction/distance relationship found in the Gravity Model.