It is well known that a town bypass will improve road safety. Elvik Et. Al. (2001) found that the reduction in injury crashes equated to approximately 25%, but that one factor in the success of this was the treatment/management of the old highway.
At the time the bypass opens, there is wonderful opportunity to transform the old highway into a lower speed, active transport corridor that services the township.
Reference: Elvik, R.; F. H. Amundsen, & F. Hofset. (2001). Road safety effects of bypasses. TRB, paper 01-0525. Transportation Research Board, Washington DC