This paper is the first of a two-part series summarizing precast concrete bridge substructure systems and details for seismic regions. The first paper is based on the 2004 FHWA/AASHTO International Scan on Prefabricated Bridges and the recently completed San Mateo-Hayward project recently completed by the California Department of Transportation (Caltrans). Emulative systems and details include a partially-precast segmental pier system, continuity details, and a partially-precast bent cap system. Even use of partial precast components in a precast bridge system allow for significant benefits over traditional cast-in-place construction, including reduced traffic disruption, environmental impact, and/or life cycle cost; improved work zone safety, constructability, and/or quality. The companion paper will introduce NCHRP Project 12-74, “Development of Precast Bent Cap Systems for Seismic Regions”, including emulative and jointed system concepts, research progress, and end products.