 The history of Highway 140 begins in May 1966 , when the St. Lawrence Seaway Authority received Federal approval for the Welland Bypass , a 13 @.@ 4 @-@ kilometre ( 8 @.@ 3 mi ) channel that would serve to bypass the canal through downtown Welland , where several crossings proved to be a hazard for shipping traffic and the shipping traffic an impediment to pedestrian and vehicular traffic . The new channel would be dug out and flooded , providing the opportunity for the construction of cheap cut and cover tunnels beneath the channel . By 1968 , construction was underway on tunnels at East Main Street and at the Port Colborne – Welland townline . 
