The removal of an intersection at Front Street in Sarnia made the entire route a controlled-access highway.

Motorists crossing into Michigan at the western end have direct access to Interstate 69 (I-69) and Interstate 94 (I-94) into Port Huron; motorists crossing onto the Canadian side from the east end of I-69 and I-94 have access to Toronto via Highway 401, and onwards to Montreal via A-20 in Quebec.

After descending over the village of Point Edward and passing through a customs plaza, the freeway curves as it crosses Front Street (former Highway 40B) and a former railway line.

[18] After passing an interchange with Forest Road, the freeway is crossed by London Line and momentarily diverges from its straight alignment to dip south of Warwick.

It continues 25 kilometres (16 mi) east through large patches of farmland, then meets with Middlesex County Road 81 (Victoria Street) at an interchange as it passes north of Strathroy.

[24] Since completion as a four-lane route, expansion work has been concentrated on the portion of the freeway in Sarnia approaching the border crossing.

[20] The short 6.1-kilometre (3.8 mi) dual highway was built as an approach to the Blue Water Bridge, which itself opened to traffic October 10, 1938.

[27][28] On February 28, 1968, a 98-kilometre (61 mi) extension towards London was officially announced by Minister of Highways George Gomme.

In addition, the removal of the Front Street intersection in Sarnia made the entire route a controlled-access highway.

[24] In 1997, noise barriers were erected upon both sides of the highway between Colborne Road to just east of the Howard Watson Trail.

[12] However, the Sarnia-Lambton Chamber of Commerce was concerned that the new noise barriers would cause travelers to overlook the city.

For the overpass carrying eastbound highway traffic, the acceleration lane which previously served the now-removed loop ramp in the SW quadrant was instead allocated to a new on-ramp from the Canada Border Services Agency secondary inspection; previously transport trucks exiting the customs plaza had to make a right-turn from Marina Road to the highway which caused considerable congestion.

[38][39][40] On Monday, December 13, 2010, a whiteout caused by lake-effect snow squalls left an 80-kilometre (50 mi) stretch of Highway 402 closed for several days.

Although the entire distance between Sarnia and London is subject to occasional snow squalls and whiteout conditions, they usually dissipate or move in less than a day.

[41] Defence Minister Peter MacKay sent two Canadian Forces Griffon helicopters and a C-130 Hercules to Sarnia to aid in the search-and-rescue efforts.

The new four-lane roadway is divided into specific lanes for cars, trucks, local traffic, and NEXUS card holders.

[46][47] Between 2004 and 2013, the speed limit along the westbound lanes from Airport Road westward was reduced from the standard 100 kilometres per hour (60 mph).

[48] On January 5, 2013, a temporary vehicular roadblock was created at the Blue Water Bridge as part of the "Idle No More" protests by First Nations groups.

[49] Later that year, another protest was held west of Strathroy on October 19, advocating against wind turbine construction.

The rolling protest of about 150 vehicles, including farm equipment, was monitored by the OPP and required intermittent ramp closures to the westbound lanes.

The trucking company, under the Highway Traffic Act, was held liable and had to compensate the Ministry of Transportation of Ontario for the repair costs.