Lucid Act of 2015

Makes eligible for federal-aid highway project grants a state whose law legalizes the possession or use of marijuana with or without medical justification only if that state:

• has in effect a law prohibiting an individual from driving or being in actual physical control of a motor vehicle while impaired by marijuana, and
• enforces that law using training and methods for determining cognitive or physical marijuana impairment.

Exempts those states from specified administrative penalties.

Revises the terms "driving while intoxicated" and "driving under the influence" to accord with this Act. Subjects repeat offenders to minimum civil and criminal penalties for driving a motor vehicle while impaired by marijuana in those states.

Directs the Administrator of the National Highway Traffic Safety Administration to:

• study through scientific testing the extent to which marijuana impairs an individual's ability to drive a motor vehicle; and
• issue a report, and make it available electronically to the public, with recommendations to states on how to prevent marijuana-impaired driving.