Assessing the impact of transit accessibility on employment density: A spatial analysis of gravity-based accessibility incorporating job matching, transit service types, and first/last mile modes

Transportation economics studies show that the activity density, in particular, employment density, is influenced by availability and quality of transportation infrastructure and services, including public transit. These studies also show that businesses and economic activities may have unique requirements, preferences, and characteristics, which may lead to varying effect of transportation on different sectors. However, the relationship between transit infrastructure and employment density has been examined mostly using simple transit proximity distance or travel time in the past research and few have used transit accessibility, and none have accounted for first/last mile (FMLM) modality, different public transit service type, and job matching mechanisms. This study attempts to fill these gaps by utilizing a new accessibility measure that is adaptive to the aforesaid features and comparing its relationship with employment density across various industries. The results show a positive and significant relationship between employment density and bus service accessibility for all industrial sectors, while the effect of light rail service is significant only for finance, real estate, insurance, food, and accommodation industrial sectors, and when FMLM modality is driving. Proximity to public transit was found to be a stronger predictor of job density than accessibility. Additionally, the effect of closeness to highway network was almost twice the effect of transit proximity for all sectors, especially for blue-collar jobs. The results also highlight that industrial sectors tend to cluster in areas with higher employment diversity but are indifferent towards higher land use diversity. These results signify several challenges in transportation equity and multimodal planning and policies. Improving regional public transit integration through coordinated physical infrastructure, fare systems, and schedules, along with enhancing walking amenities in key areas, could improve connectivity between activities. Additionally, incorporating equity considerations into land use planning, such as through distributional impact analysis, can help monitor and ensure equity in future urban developments.