House committee substitute makes the following changes to 1st edition. Provides that a law enforcement agency conducting a checking station may designate a pattern involving any type of commercial motor vehicle as defined in GS 20-4.01(3d). Adds that the provisions of new subsection GS 20-16.3A(a1) apply to GS Chapter 20 only and are not meant to restrict any other type of lawful checkpoint or roadblock. Removes provision concerning written policies. Makes the law effective December 1, 2011, and applicable to offenses committed on or after that date.