This study sought to evaluate the impact of street crossing infrastructure modifications on park use and park-based physical activity in a low-income and African American community. A five-lane major highway created an access barrier between low-income housing units and the local neighborhood park in Columbia, Missouri. The installation of a signalized pedestrian crosswalk provided an opportunity to conduct a natural experiment to examine the effect of improved safe access upon community active living behaviors. Direct observation using SOPARC was collected prior to the crosswalk instillation in June 2012, after the crosswalk installation in June 2013 and again as a follow up in June 2014 during the same two-week period to assess changes in total park use and total energy expenditure by age, gender and race/ethnicity. Analysis of covariance models, controlling for temperature examined changes in total counts and total energy expenditure using pairwise Sidak post-hoc comparisons. Total park use increased from 2012 (n = 2080) to 2013 (n = 2275) and remained constant in 2014 (n = 2276). However, despite increases in safe access and overall park use, there was a significant decrease in total energy expenditure following the installation of the crosswalk that was sustained in 2014. This study shows that increasing safe access to parks primarily positively influences park use but not park-based physical activity. While improved safe access is encouraging greater park use, there is a need for future research to examine additional factors such as social support, programming and environmental changes to engage community members in park-based physical activity.