Traffic Control Devices, sign number M1-1, which states specifically on page I-1 that: Any traffic control device design or application provision contained
DescriptionI-605 (CA).svg English: 25 in by 30 in (635 mm by 762 mm) Interstate shield, made to the specifications of the 1971 Caltrans sign drawing (still
DescriptionI-605 (1961).svg English: 30 in by 25 in (750 mm by 625 mm) Interstate shield, made to the specifications of the 1961 MUTCD (specs from Caltrans)