The following notes are provided to help APIS users interpret material from the NHTSA Digests of State Alcohol-Highway Related Legislation that has been posted on the APIS Web site.
1. The information presented in the comparison tables for this section of the APIS Web site has been copied directly from NHTSA Digests by APIS staff without further analysis or review of the underlying legal research. Legal citations and notes are presented as they appear in the Digests and do not conform to citation conventions used elsewhere on this Web site.
2. State law may permit local jurisdictions to impose requirements in addition to those mandated by State law. Alternatively, State law may prohibit local legislation on this topic, thereby preempting local powers. The NHTSA Digests do not document policies established by local governments.
3. Although some of the NHTSA Digest topics address the same subject matter as APIS policy topics, the Digest and APIS use distinct coding methods, definitions, and quality assurance procedures. Data from the two resources should not be combined without taking these differences into account.
4. The NHTSA Digests do not provide effective dates for policy enactments. If a policy became effective at any time in a given year, it is shown as in effect as of January 1 of the following year without additional detail.
5. In some instances, differences between the data for a State from one year to the next may result from modifications of NHTSA's research methodology over time rather than actual changes in the law.
6. NHTSA's research coding conventions for exceptions to prohibitions against underage consumption, possession, and sale-purchase have changed over time. As a result, the data for these variables contain many changes from year to year that do not reflect changes in the law. Because of these inconsistencies, the Changes over Time and Timeline tables are not presented.