New York Gov. George Pataki (R) plans to impose new state vehicle emissions standards that are stricter than federal requirements, adopting the set of standards that is now in place only in California. Massachusetts has signaled its intention to follow suit, a development that is expected to help push the entire auto industry to develop cleaner cars, vans, and trucks. The standards would take effect in the 2004 model year and become stricter each year until 2010, requiring new cars to cut their pollution levels by more than half, and requiring SUVs, trucks, and vans to make even greater reductions. California and New York are the two largest vehicle markets, and with Massachusetts they account for about one-fourth of the national market. Enviros and New York officials are predicting that this step could effectively set a new national standard for vehicles because automakers don’t like making cars to different standards for different states.