Ontario Highway 420

Construction of the Roberts Street link between the QEW and the Rainbow Bridge, February 13, 1941

Similar angle in the spring of 1942

The history of Highway 420 predates its designation by nearly 75 years, tied in with the crossing of the Niagara Gorge between the twin cities of Niagara Falls, Ontario and Niagara Falls, New York. The first level crossing between the two cities was the Honeymoon Bridge, constructed in 1898. The 14 m (46 ft) wide structure spanned 255 m (837 ft) between the Canadian and American sides, 58 m (190 ft) above the Niagara River. Its narrow design proved to be a fatal flaw, and on January 27, 1938, under the weight of a massive ice jam in the river, the structure collapsed.[13] A day later, the owners of the previous bridge—the International Railway Company (IRC)—as well as Ontario Minister of Highways Thomas Baker McQuesten announced intentions to construct a new span; a long political battle ensued for several years over the merits of private or public ownership of border crossings. In the end, the Niagara Falls Bridge Commission (NFBC) paid the IRC $615,000 to purchase the right-of-way of the old bridge as well as the rights to construct the new one.[14] The future Rainbow Bridge was dedicated by King George VI and Queen Elizabeth on June 7, 1939, just hours after the couple dedicated the QEW.[15]

On May 16, 1940, Samuel Johnson, the vice-chair of the NFBC, and McQuesten, who along with his parliamentary role was chair of the commission, ceremonially turned the first sod for the new bridge using a two-handled shovel.[14] Construction had begun two weeks earlier on May 4.[15] The new bridge was assembled over the following 18 months; the design was prepared by New York engineering firm Waddell & Hardesty and supervised by the Edward Lupfer Corporation, the latter the designers of the Peace Bridge.[16] The new structure was located 167 m (548 ft) downstream from the Honeymoon Bridge, as the gorge is slightly wider at that point, resulting in a 288 m (945 ft) span.[17]

Meanwhile, McQuesten was overseeing construction of the QEW between Toronto and Fort Erie. The new dual highway, inspired by German Autobahns, was the first of its kind in Canada.[lower-alpha 1] The outbreak of World War II in September 1939 temporarily halted McQuesten's ambitions, as funding was quickly shifted to the war effort. As a result, construction on the new superhighway was put on hold south of Niagara Falls. McQuesten officially opened the QEW on August 23, 1940; the pavement ended south of Lundy's Lane.[18] Despite the war, work began on a link between the opened QEW and the Rainbow Bridge through the centre of Niagara Falls. This link would not be completed in time for the opening of the new bridge.[19]

On November 1, 1941, the Rainbow Bridge was officially opened during a simple ceremony. The oldest living couple known to have wed in Niagara Falls, a pair from Pennsylvania, were the first to cross, followed by a newlywed couple from Georgia. This symbolically tied the history of the two bridges together, and was followed by McQuesten and Johnson walking towards the centre of the structure from the Canadian and American sides, respectively, and shaking hands at the centre. Several pyrotechnic explosions at both ends capped the ceremony, and the bridge was opened to traffic.[14]

Regional Route 420's terminus at Falls Avenue in Niagara Falls near the Rainbow Bridge and Clifton Hill

Work continued on the four lane bridge approach throughout 1941, and by mid-1942 it was possible to drive directly from the bridge onto the QEW. The new link featured a traffic circle at Dorchester Road as well as at the QEW.[16] At the time the new link was designated temporarily as part of the QEW[20] (decades before receiving its own unique route number of Highway 420), as a result it was referred to by several names including the Queen Elizabeth Way Extension (and known by locals for decades as the "Queen E Extension")[21] and the Rainbow Bridge Approach.[16]

At the same time construction on QEW between Niagara Falls and Fort Erie, was underway, but the ongoing war delayed its completion. As an interim measure, four gravel lanes of the highway was opened during the summer of 1941, then two lanes of pavement were laid in 1946, and the four-lane extension was fully paved and opened on October 14, 1956. Bypassed by the new QEW extension to Fort Erie in 1941, the Niagara Falls bridge approach became a spur route that was no longer part of the QEW so it was officially named the Rainbow Bridge Approach for the next three decades.[22]

During the mid-1960s, the Department of Highways examined the possibility of extending the freeway portion of the route east towards the Rainbow Bridge. They began to purchase properties lining Roberts Street in 1966.[23] In 1971, construction began on a four-level interchange between the QEW and the Rainbow Bridge Approach. This removed the two traffic circles along the approach.[8] The interchange between the QEW and Lundy's Lane (Highway 20) was also removed; instead, the Rainbow Bridge Approach ends with an at-grade intersection with Montrose Road which in turn connects to Lundy's Lane.[24] By April 1972, the Rainbow Bridge Approach was designated as Highway 420.[25][26]

A traffic circle connected Highway 420 and the QEW until the 1970s

In 1998, the Niagara Falls Transportation Study was released, recommending that Roberts Street be rebuilt as a gateway to the city as opposed to a freeway. Highway 420 east of Stanley Avenue was transferred to Niagara Region.[23] In the early 2000s, Highway 420 from the QEW interchange to Drummond Road was reconstructed with high-mast lighting poles and an Ontario tall-wall concrete median Jersey barrier, similar to the upgrades that other high-traffic provincial freeways received around that time. The rest of the route from Drummond Road eastwards (including Regional Road 420) was instead upgraded to 15-metre (49 ft) and 12-metre (39 ft) decorative "ER" lightposts, to commemorate the route's historical status as the original routing of the QEW and its historical tie to the Queen Mother.[27] The "ER" style lighting poles are themselves a historical decorative lighting pole model, discontinued decades earlier, that was revived originally for the early 2000s Highway 420 reconstruction and would also be later used for QEW's bridges in Mississauga, Oakville, and St. Catherines. The Drummond Road and Portage Road overpasses that originally built in 1941 and rehabilitated in the early 1970s were demolished in 2004; their new replacement bridges plus Highway 420's concrete median barrier feature decorative stone facades, which in combination with the "ER" light poles restores the heritage look that was lost in the 1970s reconstruction.

On September 23, 2010, Highway 420 was designated as the Niagara Veterans Memorial Highway.[28] On January 31, 2012, Niagara Regional Council approved the renaming of Roberts Street and Newman Hill as an extension of Falls Avenue, beginning March 1. Prior to this, Falls Avenue curved into Newman Hill at the Rainbow Bridge.[10]

In 2016, the flyovers of the Highway 420-QEW interchange were rehabilitated.