In 2017 a new law was placed in effect that the left lane of VA interstates were for passing ONLY. This law is not being enforced adequately. And signage along the interstates are sorely lacking as a reminder for all motorists. By increasing the signage frequency (every 20-30 miles), motorists would most likely heed the law. On I-81 the other night, 7 tractor trailers were in the left lane from milepost 220 to 245 and little to no traffic was in the right lane. Please consider posting signs regarding the left lane as passing only since it is THE LAW now!