Requires States to limit driving after a DWI conviction to vehicles equipped with ignition interlock devices for at least 180 days and to enforce a violation-free period before removing that restriction. If a State fails to meet this national standard, a percentage of certain Federal highway funds will be withheld (3% beginning Oct 1, 2026; 5% beginning Oct 1, 2027 and each year after) until the State comes into compliance.

Sets rules for how withheld funds are handled and returned, defines key terms (for example, ignition interlock and DWI), and makes conforming and clerical changes to Federal highway law. The law is intended to reduce repeat impaired-driving offenses and fatal crashes by requiring interlocks and creating a financial incentive for State compliance.