According to MSP that officer is wrong.
This is the email they replied back to.
What is the speed limit of an on ramp/acceleration ramp of a freeway?
Thank you for the question. The Michigan State Police (MSP) cannot provide legal advice or offer an advisory opinion as to whether a particular activity is legal or illegal as a matter of law. Such determinations would necessarily depend on the specific facts and circumstances, and any enforcement action or charging decision is left to the discretion of local police and prosecuting officials and ultimately the courts to decide. If you need specific legal guidance, you should seek assistance from private legal counsel.
Nevertheless, MCL 257.26 defines a “Limited access highway” as “every highway, street, or roadway in respect to which owners or occupants of abutting lands and other persons have no legal right of access to or from the same except at such points only, and in such manner as may be determined by the public authority having jurisdiction over such highway, street or roadway.”
Limited access highway points, or “ramps” are designed so motorists can accelerate as quickly as possible to the posted limited access highway speed limit and safely merge into traffic. Unless a white/black speed limit sign is posted on the ramp itself showing a lesser speed limit, then the motorist may accelerate to the freeway posted speed limit.
I hope this information was helpful.
Michigan State Police
Legal Resources and Education Unit
P. O. Box 30634
Lansing, MI 48909
1-855-677-5345
"A PROUD tradition of SERVICE through EXCELLENCE, INTEGRITY, and COURTESY"