Synthesizing Short-Term Accessibility Change
It is important to recognize that the evaluations of job access by auto and job access by transit reflect the same changes in land use. The changes in job locations between 2022 and 2023 produce a clear, consistent increase in job access by auto for all Minneapolis locations, while the impact on job access by transit is minor overall, and many locations see a small decrease.
How do the same changes in land use have such disparate access impacts for different modes? The answer can be found through understanding that access depends both on the quantity and the location of destinations. Between 2022 and 2023, the metropolitan area that contains Minneapolis saw a net increase of +56,700 jobs (about 3% of the regional total number of jobs). That is good news, and it would be reasonable to expect to see a comparable increase in job access. But that total job growth figure doesn't provide any information on where the new jobs are located. If all the job growth happened in places that are hard to reach, we'd expect a small increase in access; if all job growth was in places that are easy to reach, we'd expect a larger increase in access.
Another complication is that the net increase in jobs is not only from growth. In reality, jobs are also lost and change locations as businesses close, shrink, and/or relocate. Just as with job growth, the impact that these changes have on job access depends on location. If a business was located in a very hard-to-reach location, its closure might have only a small negative impact on job access. If a business moves to a location that is easier to reach, the number of jobs doesn't change but access to jobs increases.
These insights help interpret the diverging trends in auto access versus transit access in Minneapolis. Every location in Minneapolis saw a clear and consistent increase in job access by auto associated with the 2022-2023 land use changes. From this we can conclude that the overall trend was that jobs increased in places easily reachable by car. Moreover, the coordination between job locations and ease of reach (by auto) improved enough to overcome measurable increased road congestion and produce a net positive change in job access by auto.
For transit, the 2022-2023 land use changes are associated with a mix of job access gains and losses, with a small net positive change. This implies that overall, job growth, loss, and location were unrelated to ease of reach by transit. New jobs were about equally likely to arrive in locations easy or hard to reach by transit, and an easy-to-reach location had a roughly even chance of gaining or losing jobs. Lacking coordination with ease of reach by transit, and combined with a wide range of both negative and positive access changes from transit travel times, these job changes contributed to a largely static level of job access by transit. Meanwhile, changes in transit schedules resulted in widely varying changes in travel times to those jobs depending on the location of the origin.
This analysis accounts for the geographic change experienced in places within a single city. A third dimension to consider is who lives in the places which have changing access–for whom is it becoming easier or harder to reach these economic opportunities? Where might additional residences lead to higher average accessibility for the region by connecting people to destinations, without even changing the transportation network? These questions take performance measurement toward the long term.