
The 66 name is explained by a remark that a car using Phillips fuel was travelling at 66, rather than 60, miles per hour. This occurred on U.S. Highway 66, envisaged as the axis of the distribution network. The shield, shaped like the U.S. highway route marker rather than interstate or state signs, had been used since 1927. Brown 1982 records the livery under Philtankers.