Bill
HB 4470
Designates the Mackinac Bridge's nonpublic portions as a key facility, elevating trespass to a felony and banning drones that interfere with its operations.
HB 4470 (Introduced May 7, 2025) – Highways: bridges; Mackinac Bridge; designate as a key facility (amends MCL 750.552c)
Overview
House Bill 4470 would designate certain nonpublic portions of the Mackinac Bridge as a “key facility” under Michigan law and extend existing trespass and unmanned aircraft restrictions to those parts. The measure aligns the Mackinac Bridge with other key facilities already listed in law and adds a specific prohibition on drones that interfere with operations at key facilities. It also clarifies that a barrier left open for official business during normal operating hours is not a defense to trespass.
What the bill would do
- Add the nonpublic portions of the Mackinac Bridge to the list of key facilities, subject to the same posting and barrier requirements that apply to other key facilities.
- Elevate trespass on a key facility (when it is completely enclosed by a barrier and posted) from a misdemeanor to a felony (punishable by up to 4 years in prison or a $2,500 fine, or both).
- Prohibit knowingly or intentionally using an unmanned aircraft (drone) in a manner that interferes with the operations of a key facility, a correctional facility, or another law enforcement facility (felony with up to 4 years’ imprisonment or a $2,500 fine, or both).
- State that the barrier being left open during normal operating hours for official business is not a defense to trespass on a key facility.
- Expand the “key facility” definition to specifically include the Mackinac Bridge portions not open to the public.
Key provisions and specifications
- Posting and signage: Key facilities must be clearly posted against entry; signs must be at least 50 square inches with letters at least 1 inch tall and visible at all entry points.
- Penalties: Violations of trespass provisions for key facilities are felonies (up to 4 years imprisonment and/or up to $2,500 fine).
- Drone prohibition: Prohibits drones that interfere with facility operations; violators face felony penalties.
- Defense limitations: No defense based on barrier being left open for official business during operating hours.
- Existing key facility examples remain listed (chemical facilities, refineries, electric or gas utilities, water facilities, fuel terminals, transportation facilities, pulp/paper facilities, pharmaceuticals, hazardous waste sites, telecom facilities, etc.), with Mackinac Bridge portions added to the list.
Who is affected
- Owners/operators of key facilities (including those listed and the Mackinac Bridge segments designated as key facilities).
- Individuals who may trespass on or attempt to access designated key facilities.
- Drone operators and entities using drones near key facilities.
- Law enforcement, prosecutors, and courts handling trespass and related offenses.
- Potential fiscal impacts on prisons, probation, and local courts; any heightened fines could bolster funding for public and county law libraries.
Procedural status and timeline
- Introduced: May 7, 2025; assigned to the Committee on Transportation and Infrastructure.
- Legislative actions show progression toward second reading; as of late 2025, the bill had been reported with a recommendation without amendment and referred to second reading.
- Related legislation: Senate companion SB 2179 (and a historically similar bill in 2021-22 for context).
- Fiscal impact: Indeterminate; potential increases in state prison and probation costs, with estimated 2024 per-prisoner costs around $46,200 and parole/probation costs around $5,500 per offender; local court impacts depend on enforcement and caseloads.
Notes
- The bill mirrors similar proposals in prior sessions and is designed to strengthen protection of critical infrastructure, now explicitly including nonpublic Mackinac Bridge segments.
Compiled from official sources — confirm details with the bill’s official record.
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