GRAND HAVEN, Mich. (AP) - Shake your - mailbox? Indeed, that's the message in many areas of Michigan where mailboxes are attached to posts at the end of a driveway. As another winter approaches, road commissions are reminding residents to check the stability of their mailbox. A weak mailbox post is no match for snow coming off a plow at 35 mph. The Ottawa County Road Commission in western Michigan says it's "no picnic" to dig out a fallen mailbox and try to reinstall it in frozen ground. Alex Doty of the road commission says mailboxes can be a serious hazard along a road and a liability risk for homeowners.