A thought - try repairing the game, that might get rid of the orphaned vehicles.
Exit the game, then in Origin, right-click the SimCity icon, choose "Repair".
If that doesn't work, you could try SimCity Recovery - default location C:\Program Files (x86)\Origin Games\SimCity\SimCityRecovery
Run SimCityRecovery.exe "As Administrator" from the file location. Don't try using any menu shortcuts, they point to some online help file that no longer exists.
Exit the game, then in Origin, right-click the SimCity icon, choose "Repair".
If that doesn't work, you could try SimCity Recovery - default location C:\Program Files (x86)\Origin Games\SimCity\SimCityRecovery
Run SimCityRecovery.exe "As Administrator" from the file location. Don't try using any menu shortcuts, they point to some online help file that no longer exists.