About Indiana Sign & Barricade (ISB) Flagging. Established in 2007, ISB is a DBE Certified laborers union signatory company that sells, rents, and installs road-safety related products and services for the Indiana Highway Construction Industry. In 2021, ISB opened its Flagging Division at 911 Markley Drive in Plymouth, Indiana and has quickly become the leader in work zone safety for Utility companies, Primes and state and federal construction pr...
