“City Greenways” is a concept proposed as a part of Portland’s 2035 Comprehensive Plan, which calls for a citywide network of park-like pedestrian and bicycle friendly streets crisscrossing the city at roughly three-mile intervals. This research establishes several approaches to measure the transportation network impact of the “City Greenways” and relate bicycle network measures to economic and social equity outcomes.
Expanding upon existing literature, we derived three sets of bicycle accessibility measures (BAMs). They are distance-based BAM, destination-based BAM, and low-stress network-based BAM, which incorporate different components of a comprehensive bicycle network. The distance-based BAM measures accessibility of the active transportation infrastructure via a proximity measurement; the destination-based BAM measures the ease of access to the closest five important employment, retail, service and parks/recreation destinations; and the low-stress network-based BAM measures the comfort levels and willingness to use active transportation modes as a travel option, incorporating bicycle level of stress factors to determine the overall accessibility of the urban greenway network. The three sets of defined BAMs were applied to Portland’s current (2016) and proposed 2035 scenarios. We found that after the implementation of Portland’s “City Greenway” network, all three sets of BAMs showed improvements in accessibility compared to the existing network, although at varying degrees. The improved urban greenway network not only decreased the travel costs of active transportation due to well-connected network and higher comfort and safety levels of cycling, it would also provide increased accessibility to important destinations at lower stress levels within the same distances.
Next, we explored the relationship between the bicycle accessibility levels of the urban greenway network and economic indicators. We found positive correlations between two BAMs (distance-based BAM and low-stress network-based BAM) with the number of jobs that are located in each census block. The low-stress network based proximity BAM appears to be the more preferred measure, due to the statistically significant correlations that we found. In addition, the hedonic price model indicated that higher BAM scores were associated with higher property values, particularly for multi-family homes. In general, better BAMs were associated with higher levels of economic activities.
The spatial equity analysis examined the how bicycle accessibility is distributed across the metropolitan area and amongst identified historically marginalized communities (including communities with higher populations of people of color, low-income, limited English proficiency, older adults and younger persons), and how the proposed 2035 City Greenways plan might impact these communities differently. We found that the 2035 City Greenways plan, as measured through BAM slightly favor the disadvantaged population. While the distance-based BAM showed significant improvements in accessibility for many of the transportation-disadvantaged communities, the low-stress network-based BAMs showed tempered improvement in these communities. These results indicated that while residents might be better able to access the urban greenway network as more bicycle infrastructure was built, it did not necessarily translate into better access to important destinations without complementary economic development and land use policies expansion along the transportation infrastructure. It also underscores the importance of complementary economic development and land use policies that expand the spatial distribution of important destinations while investing in urban greenway infrastructure or other transportation network improvements.