HELIX Environmental Planning (HELIX) conducted technical analysis focused on mobile-source greenhouse gas (GHG) emissions for an infill development project proposed by the City of National City. The proposed project would consist of constructing 92 residential units, expanding the Paradise Creek Educational Park and Trail, and building off-site transportation improvements including class II bicycle lanes, pedestrian pathways, and Americans with Disabilities Act (ADA) enhancements at key intersections within the public right-of-way. HELIX prepared a letter report in accordance with California Air Resources Board requirements for the Affordable Housing and Sustainable Communities program that demonstrated reductions in mobile-source GHG emissions from proposed project features.