RCW 46.61.410
Intent-1987 c 397: "It is the intent of the legislature to increase the speed limit to sixty-five miles per hour on those portions of the rural interstate highway system where the increase would be safe and reasonable and is allowed by federal law. It is also the intent of the legislature that the sixty-five miles per hour speed limit be strictly enforced." [ 1987 c 397 § 1.]
Federal requirements-1977 ex.s. c 151: See RCW 47.98.070.