This is a Welcome sign for the city of Halsiburg (2nd in series) which lends its name to the fictional route. It will be seen on roads as they cross the Halsiburg city line. This is a modification of a sign provided for reskinning by Andrew Luimes (TransportFan) who deserves most of the credit.
He was kind enough to publish this with a 'Feel free to reskin!' license, the terms of which are posted here unmodified. Maximum respect bro!