Excess Commuting and JobHousing Imbalance in Warren County

Excess Commuting and Job-Housing Imbalance in Warren County, Kentucky Caitlin Hager and Jun Yan, Center For GIS, Western Kentucky University Abstract: Excess commuting (EC) is a concept first developed by Hamilton (1982) to measure the degree of commute distance explained by the spatial separation of job sites and households. The method is applied to a smaller metropolitan area and compared to previous studies done in larger urban areas. Methodology: EC can be defined as the portion of all workers’ commute as a whole that is over and above the minimum required by the spatial distance between their residences and the job sites. It is a “benchmark” for evaluating jobs-housing imbalance and characteristics of urban form. It is calculated via a linear programming process that swaps workers to “new” household locations in the most efficient manner by minimizing the total travel distance for all workers. In this study, we also conducted a worstcase baseline analysis by allocating workers in the most inefficient way (maximizing the total travel distance). This measure gives the commute potential of a region and is determined by both transportation network and distribution of jobs and workers. A B C D E F Minimize or Maximize Treq = subject to: Comparison Analysis: The analysis is conducted at TAZ level in the Bowling Green Warren County MSA using CTPP 2000 data. The above maps show Discussion: Excess Commuting (minimization) and Commute Potential (maximization) can be respectively calculated as follows: Warren County has an EC of 35%, which means, as a whole, 35% of total current total travel distance is unnecessary under an optimal scenario. Compared to previous studies (E), EC of Boise, ID is 48%; Omaha, WI 64%; Baltimore, MD 62%; Boston, MA 67%; Atlanta, GA 57%, Warren County, as a smallsize metro, has a relatively small EC, considering that Bowling Green is one of the fastest growing cities in Kentucky and it functions as a regional employment center. the actual commutes (A), minimized commutes (B), and maximized commutes (D) by drive-alone commuters (the most common mode in small-size cities). As shown in B, a large number of shorter commuting trips is increased drastically and the cross-town trips are minimized. On the other hand, a large number of longer trips rises under maximization (D), indicating the increased cross-town trips. In addition, under optimum minimization, intra-zonal trips are increased (C) but totally eliminated under maximization. Compared with other places in U. S. , Bowling Green has relatively inefficient commutes (F), with 6. 47 miles actual, 4. 2 miles minimum optimal, and 9. 16 miles maximum optimal mean travel distance. Job-Housing Imbalance: Ratio of jobs to matched workers (JHB) for all and selected industries. Job-poor areas generate commutes; job-rich areas attract commutes. Blue zones indicate a low JHB; yellow - balanced; red - a high proportion of jobs to matched workers. Reference: Hamilton, B. 1982. Wasteful commuting. The Journal of Political Economy 90(5): 1035 -53.