SAN FRANCISCO - A new study suggests that a California law granting driver's licenses to hundreds of thousands of people in the country illegally has reduced the likelihood of hit-and-run collisions.

Researchers at Stanford University's Immigration Policy Lab estimated that granting the driver-only licenses appears to have reduced hit-and-run crashes and saved insured drivers about $17 million that they would have absorbed from at-fault drivers fleeing collisions to avoid possible arrest.

Jens Hainmueller, faculty director of the policy lab, said the study released Monday was conducted because of a lack of data when California debated its law.

Andrew Gelman, director of the Applied Statistics Center at Columbia University, said he would want more evidence to determine that the law decreased hit-and-run collisions,

However, he said the data does make it clear that granting licenses did not decrease safety.

The study was published by the Proceedings of the National Academy of Sciences.