An Introduction to Systems Traffic Modeling in Florida
Urban transportation planning is the process used in urbanized areas to analyze and plan for current and future transportation needs. An important element of this process is the forecasting of travel demand using computerized simulation models.The term FSUTMS (Florida Standard Urban Transportation Model Structure) is used to represent a formal set of modeling steps, procedures, software, file formats, and guidelines established by the Florida Department of Transportation (FDOT) for use in travel demand forecasting throughout the state.
The primary objective of travel demand forecasting is to forecast the effects of various policies, programs, and projects on highway and transit facilities. These impacts are commonly quantified by representing the projected demand in terms of forecasted traffic volumes and transit ridership.
Travel demand modeling involves a series of mathematical models that simulate human behavior while traveling. Modelers execute a sequence of steps that answer a series of questions about traveler decisions and simulate choices that travelers make in response to a given system of highway and transit alternatives. The travel simulation process follows trips as they begin at a trip origin zone, move through a network of links and nodes and end at a trip destination zone. These traffic analysis zones (TAZs) are composed of land use with similar area type characteristics. TAZs that produce trips are mostly residential and those that attract trips are mostly commercial.
The simulation process is known as the four-step process for the four basic models used. These are: trip generation, trip distribution, mode split and traffic assignments. Model developers calibrate these computer model simulations to match actual observed traffic for a given point in time. Planners and engineers can then use the models as a tool to project future traffic, test alternative transportation plans, and assess air quality and safety issues on the transportation system.
The Systems Traffic Modeling Section develops and maintains transportation computer models. The central office modeling section works with the districts, MPOs, cities, counties, and other government agencies in the use of these models and provides technical guidance, training, and assistance.
The Model Task Force is an organization comprising representatives from these different agencies and, through the Systems Traffic Modeling Section, establishes standards, procedures, and direction for future development and use of these models.
