In the early 1990s, site-specific studies were conducted to evaluate the seismic hazard for four New York City area transportation construction projects. The rock motions developed as a result of the four independent site-specific studies reflected wide disparities in the ground motions for the city area. An expert panel was assigned the task of developing rock motions for the New York City area that can be applied uniformly for the design of new structures and retrofitting of existing structures. Summarized are the findings and the resulting changes to the New York State Department of Transportation requirement for evaluating ground motions in the city area, namely, importance classification, performance criteria, two-level seismic hazards, and site amplification factors.