I've been in the FedroSplat long enough (and had friends in that part of Bowie) to remember when that was the actual routing of MD 450. MDOT rerouted it back in the oughts to allow for a widening of the roadway. Old 450 east of MD 197 was demolished, but west of 197 wasn't because of the need for access to developments and to Church Road. I honestly thought they'd turned that stretch back to the county, though, and that the "OLD 450" signage had been put there by the county.