I-25 north at Exit 188A - Center St (BL-25/Bus. US-87). Approaching Exit 188B - Poplar St (WY-220). Poplar Street used to have the WY-220 shield on the exit, until the eastern Casper bypass was completed. WY-220 traffic is encouraged to continue north on I-25 to Exit 189 and to follow US-20/US-26 and WY-257.