Moped rentals are controversial on Martha's Vineyard. Tourists rent them and crash them too often, or so the locals believe. Most of the moped rental businesses are right at the north end of Circuit Avenue. It looks like the town now requires them to test any potential renter to ensue they can safely operate a moped. One rental company now rents cars in addition to mopeds: "The training will be first-rate. If you cannot ride, you’re not leaving the lot. We want you to come back. If you can’t ride [a moped], you can get a car … I will not compromise on safety.” (Luckily, cars never crash on Martha's Vineyard.) I'm guessing the signage is to encourage these tourists to attempt their first moped rides on some residential road, not the main drag there. I didn't find any similar complaints regarding bikes, so I'm not sure why the signs prohibit those too.