It is 7 km long, ranges from three to seven lanes wide, and extends from the base of the Ngauranga Gorge into the Wellington CBD.

From the Ngauranga Interchange (State Highways 1 & 2), the motorway travels south across reclaimed land alongside the Wairarapa and North Island Main Trunk railway lines.

[1] U.S. consultants De Leuw Cather were engaged late in 1960 to design a motorway scheme and advise on traffic improvements within the city.

The alignment and scale of the motorway between Ngauranga and the Bowen Street overbridge as built very closely matches the original 'foothill' proposal, with the exception that the proposed interchange at Ngaio Gorge (with on- and off-ramps over the railway to Kaiwharawhara) was never completed, although the stumps of a southbound on-ramp and northbound on- and off-ramps remain visible today broadly parallel to Kaiwharawhara railway station.

Beyond the Tinakori Road on-ramp and Hawkestone Street off-ramp going south, the motorway is a considerably scaled down concept from what was initially proposed, and it was never extended as far as the Basin Reserve.

The first phase of the motorway was a 2.7 miles (4.3 km) section between Ngauranga and Aotea Quay which began with reclamation works in 1959 and opened in April 1968 as part of State Highway 2.

[5] This section included several traffic overbridges, a rail access tunnel for the Gear Meat Company and the Ngauranga Railway Bridge.

[6] Hundreds of old houses in Thorndon, including one of Katherine Mansfield's family homes, were demolished to make way for the motorway, with no assistance given to displaced tenants and homeowners.

[7][8] Public protest over the destruction of the suburb eventually led to Thorndon becoming New Zealand’s first built heritage conservation area.

[12] The overbridge passes over the Cook Strait ferry terminal and rail yards, and it crosses over the Wellington Fault.

Part of the work involved wrapping 81 of the overbridge's 125 columns with layers of a fibreglass kevlar material, filled with epoxy, so that they are less likely to fail in an earthquake.

The cemetery had long been closed to new interments, but had huge historical significance as the burial place of many early Wellington settlers, and there was controversy about disturbing the graves.

A footbridge (the Denis McGrath Bridge, named for the deputy mayor)[15] was built over the motorway to link the two now-separate halves of the cemetery.

The Terrace Tunnel, opened in 1978, passes through the crush zone of an earthquake fault line, under a populated area.

Funding for the second tunnel was indefinitely shelved in the 1970s due to fiscal pressures on government, and the beginning of far greater scrutiny of the quality of highway expenditure.

[21] It was clear that until the Wellington Urban Motorway was connected to State Highway 1 at Ngauranga Gorge, a single Terrace Tunnel would be adequate for the traffic demands of the 1970s.

[27] Although the smart motorway technology was supposed to lessen congestion and create shorter, more reliable travel times, data released after the first year of operation showed that "peak-time northbound journeys between Hobson St and Petone had actually become longer, while southbound journeys had only improved by an average of about 30 seconds".

[28] The motorway is the subject of the ongoing Ngauranga to Airport Strategic Study, which is investigating Wellington's future transport growth needs.