In February WTA undertook one of its most ambitious projects to date, a three-week closure of the 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 57,646 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 an innovative solution. The aim was to get as much done all in one go to save time, money, and minimise disruption. Most importantly, it was safer for our crews within the closure area.
Planning of this closure began six months in advance.
This included coordination of all works between WTA internal teams, local councils and utilities, and external crews such as Downer Mobile 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 2000 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 4000-5300 northbound trips and 4900-5500 southbound trips impacted per closure day. The more condensed the closure period, the fewer the trips that would be impacted overall.
Coordination of other projects and events early and an extensive communications and engagement campaign helped make the closure a success.
"Shutting down two major highways (SH1 Ngauranga SB SH2 Petone SB) simultaneously has hardly been seen before. The crew coming together played out well." - Jaymie Baker, TTM Operations Manager
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.
WTA saved $154,000 on traffic management and removed 125 hours of high-risk activities from our workers.
- 68 TTM tasks covered throughout the three weeks.
- Cost of 3 week combined closure was $240,000.
- Estimated cost of $394,000 under 68 different closures.
- Only 15 site set ups for the closure, compared to 68 if each task was completed as a separate site.
- That's 125 hours of time given back to our workers to spend time with their friends and family.
Safety was essential in reducing risk, boots on the ground and cost. Safety measures included:
- Tailgates ahead of every night closure with crews, contractors and subcontractors to set expectations, safety risks and control plans.
- Clear plans to ensure all teams were aware of each other's movements: entry, egress and transit routes.
- Localised radios and communication protocols discussed before each shift.
- Sharing of lessons from previous night closures and being proactive to anticipate safety issues.
- Removing boots on the ground by reducing risk of site set up and pack down to traffic teams - doing more work in less shifts.
RESULTS: By closing the Urban Motorway at night for three weeks, many different teams were able to access the corridor and complete necessary works at once.
Over three weeks WTA renewed 30,974m2 of asphalt (that's 6 lane-kilometres), installed 21 electronic signs, 260m of barrier, completed 16 structural inspections, cleaned many areas of graffiti and cleared over 1km of vegetation and trimmed trees. Other activities included clearing litter, replacing signs, clearing drains and replacing damaged sump gates.
We renewed 30,974m2 (6 lane kms) of asphalt in three weeks.
Installed 21 electronic signs.
Cleared over 1km of vegetation and trimmed trees.
260m of barrier.
16 structural inspections.
Cleared litter, replaced signs, cleaned drains and replaced damaged sump gates.
People travelling in and out of Wellington experienced minimal delays to their journeys during the closures, and we only received 3 customer complaints.
From when the closures were being set up at 7pm, till 9pm, delays peaked at 7-9 minutes on most nights compared with what those journeys would normally take at that time of day. After 9pm, people were only delayed by approximately 3 minutes from normal. Even with these delays, this is still a lot less (10+ minutes) than the delays people experience daily during the morning and afternoon peak times on the network.
There were only 3 complaints received by customers through the 3 week closure period. Planning noisest works first and reaching all neighbouring businesses and residents prior to the closure meant people were prepared for disruption and delays in advance.