The owner(s) or user(s) that benefits from it's use. Like a HOA agreement in a condo.
The owner.
Cops
The State of Michigan does nor require a Private Road Agreement. But, it's a good idea. The State does require that if you sell a house on a private road that you disclose if the road is not required to be maintained by the county.
a private, third party contractor
Road Holding
are razor pocket rockets street legal on a private road?
only by agreement
yes it does
If a landowner sells lots (or a single parcel) that front on a private road, generally, the law provides the right to each lot owner and their invitees to use the road for access whether or not that right is granted in the deed. Town services such as police, fire and ambulance can also use the road.
By permission or invitation of the road's owner.
If the road is yours, yes.
Generally, if you were sold a lot that has frontage on a private road you also acquire the right to use the road for all purposes of a public way, in common with other owners that have frontage on the road, as long as the person who originally owned the lot also owned the road. Private road issues are complicated and you should contact the attorney who represented you at the time of purchase if you have questions about your rights.
Not unless it is done with the permission of the other property owner(s) that share ownership and use of the road.