During February 2024 the Wellington Transport Alliance (WTA) completed one of its most ambitious projects to date, a 3-week closure of the SH1 Wellington Urban Motorway.
As the main road leading into the capital city intersecting high density residential areas, the SH1 Urban Motorway is a difficult road to schedule roadworks on.
Approximately 57,500 vehicles travel this highway in and out of the city per day (5am-7pm). Completing works under lane closures or stop/go’s is inefficient, a safety hazard for crews and road users, and more expensive. WTA developed a solution to save time, money, and minimise disruption, while making sure it was safer for road workers and road users.
Planning of this closure began 6 months in advance.
This included coordination of all works between WTA internal teams, local councils and utilities, and external supplier crews for the installation of GPS antennas for telecommunications.
Considering network impacts and managing these carefully was important. Typically traffic is at its busiest from 7:00am to 6-7:00pm most days. The quietest time on the network is later in the evening through to 5-6:00am in the morning. During peak times, there are approximately 2,000 vehicles per hour. But overnight, it drops down to less than 500 vehicles per hour.
During the closure periods, from set up at 7:00pm to reopening at 5:00am, there would typical be 4,000-5,300 northbound trips and 4,900-5,500 southbound trips impacted per closure day. The more condensed the closure period, the fewer the trips that would be impacted overall.
Temporary Traffic Management (TTM) planning included careful consideration of safe and appropriate detour routes, maximising TTM resource to reduce costs, and safely managing the number of crews, vehicle movements and hazards within the closure.
Overall WTA saved $154,000 on traffic management and removed 125 hours of high-risk activities from our workers.
People travelling in and out of Wellington experienced minimal delays to their journeys, peaking at 9 minutes which is no worse than and normal rush hour, and we only received 3 customer complaints.
Planning nosiest works first and reaching all neighbouring businesses and residents prior to the closure meant people were prepared for disruption and delays in advance.
Read the full case study for the SH1 Wellington urban motorway upgrade(external link).
