Traffic safety impact of the extension of driver licenses by mail for renewal applicants with clean prior driving records.

For some 40 years the renewal of a driver licence in California has required that the person appear at a local field office periodically to pose a written and a vision screening task. Now, when drivers under the age of 70 whose prior four-year accident and conviction records showed no entries, they have the opportunity to receive a four-year license extension by mail. There was no evidence that extending licences by mail affected accidents or convictions, but the savings (reducible costs) were much.