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https://www.nationalacademies.org/trb/events

Research and Development of a 3-Item Transportation Security Index Mobility Tool

A robust transport infrastructure includes high-quality and well-connected roads in conjunction with accessible pedestrian/bicyclist pathways and mass transit approaches. Forethought into transportation policies and transportation investments play a critical role in constructing livable communities. High-quality and well-connected roads, increase the mobility of people by cutting down travel costs and times and increase safety. In addition, improved transport infrastructure provides resident access to a range of services and opportunities that they need for a better quality of life. However, when a person is unable to regularly move from place to place in a safe or timely manner due to the absence of mobility resources, that person experiences a level of transportation insecurity that directly effects quality of life. Until recently, the number of people specifically experiencing transportation insecurity in the United States had been a mystery, largely because researchers have lacked the tools to measure mobility resource needs, State DOTs cannot properly assess populations and geographies where mobility investments are needed or evaluate any mobility intervention or investment actions to properly assess the impact (positive or negative) they may have on a communities transportation insecurity. A research study published in 2022 developed a novel mobility measurement tool—the Transportation Security Index (TSI)—to quantify the prevalence of transportation insecurity in the United States. Modeled after the Food Security Index, the TSI identifies those experiencing transportation insecurity by looking at their symptoms through a 16-item tool which researchers can administer, score responses to each question, and add up the scores to come to a quantitative measure of a person’s overall level of transportation insecurity. In the research study, when the TSI tool was administered to a nationally representative sample of 2,000 adults age 25+ in the U.S. researchers documented that 1 in 4 Americans are transportation insecure. Additionally, the study revealed high correlations between transportation insecurity relative to income level and under-represented groups. Currently, the available research provides a validated 16-item longform TSI mobility measurement tool and a 6-item shortform tool. However, there are advantages of building a more concise version, if it performs as accurately as the existing tool, when assessing transportation insecurity. An abridged tool would decrease the respondent burden while increasing respondent rates. Increased response rates provide researchers more data to analyze which can provide a more accurate assessment on mobility resource needs. Additionally, developing a concise tool decreases user costs associated with administering making it an inexpensive and effective method for gathering relevant mobility data. The transportation security index mobility measurement tool offers new insights into who is experiencing transportation insecurity and the severity of the experience. The transportation security index is an essential measurement tool the Michigan DOT could utilize to (1) assess populations and geographies where mobility infrastructure investments are needed, (2) evaluate the impact of department investments on mobility approaches, and (3) trace the progress the department is making on transportation equity goals. Therefore, this research project will focus on the research and development of a cost effective, reduced 3-item TSI mobility measurement tool. Once research is complete this tool may be utilized by the department on future mobility infrastructure investments to identify travel behavior trends and patterns to inform future mobility approaches with respect to transportation equity. In this way the problem to address will be limited to the research and development of a data collection tool, and not include the deployment of that tool.