It crossed the Saint John River at the Reversing Falls Bridge before proceeding on Douglas Avenue into the north end of the city.

Over time, various sections of 2-lane controlled access highway were built to bypass the growing towns and villages, including a long section bypassing the townships of Rothesay and Quispamsis, named the Mackay Highway, having been built through a stretch of timberland formerly owned by the locally prominent Mackay family.

Several alignment options were examined with the majority of citizens wanting the highway to go north of the city through the suburb of Millidgeville from where an easier crossing of the Reversing Falls gorge could be attempted.

In a related project, in 1969, the federal and provincial governments worked with CPR to revamp the Saint John-Digby ferry service by building a new terminal in the city's west end, along with interchanges off the new expressway.

The Saint John area soon saw the growth of suburbs in the towns of Rothesay and Quispamsis in the Kennebecasis River valley, which were located just outside the Bay of Fundy's "fog belt."

Another bypass was built from Oak Bay to Digdeguash to avoid the circuitous routing down the St. Andrews peninsula and through the town of the same name.

Under the remainder of the McKenna administration's years of power (until 1997), Route 1 saw 4-lane expansion and upgrading between Lorneville to Lepreau in the west and between Coldbrook and Apohaqui (near Sussex) in the east.

After construction was completed the company formed by the consortium will be responsible for the maintenance of the highway from the US-Canada border crossing, to the interchange with Route 2 at River Glade, 15 km west of Moncton until the year 2040.

The final years of the McKenna administration saw an agreement signed with a private consortium called Maritime Road Development Corporation (led by former provincial Liberal leader and former federal Minister of Transport Douglas Young) to privately finance and build a toll highway to carry the Trans-Canada Highway (Route 2) in a new alignment from a point west of Fredericton to a point on the existing TCH west of Moncton at River Glade.

The toll issue was not without controversy as it led to the downfall of McKenna's successor, Camille Theriault in 1999 to PC leader Bernard Lord.

In December, 2013 the "One Mile House" interchange officially opened after over 4 years of construction with a final price tag of $83 million.