Do Interstates have publicly-accessible U-turn ramps in places?
Yes. These are distinct from the crossovers used for emergency and service vehicles only. Many non-Interstates have such crossovers to complete the movement from a side road where a median break is not present and a corresponding ramp would be cost-ineffective due to lack of room or light traffic usage, such as on divided, mostly-controlled-access parkways, or at the location of Michigan Lefts (see Question 3.6 ); because of the high-speed design of Interstates, these are very rare on that system. They do exist, however: There are at least 3 instances of them (I-20’s western end at I-10, W. TX, 31.085,-104.06 ; I-25 at US-85 on the north side of Cheyenne, WY, 41.23,-104.84 ; and I-55 at IL-129 near Wilmington, 41.315,-88.19), and these are signposted as full access ramps.