With traffic on Auckland motorways growing, Transit is taking proactive steps to help reduce congestion by managing its existing motorways in the best way possible. Ramp signals are designed to keep traffic flowing on the motorway and to help reduce accidents.
By separating the stream of vehicles travelling down the on-ramp, merging is made easier for those entering the motorway. It also means less impact on the motorway traffic that these vehicles are joining.
Because traffic conditions and demands are different on each on-ramp, the operating times and the green light timings on each set of ramp signals will be slightly different and customised to manage those exact conditions.
Some areas experience high demand at different times of the day to others, some have longer peak times, and most differ in the volume of traffic travelling across the ramp during peak times.
The ramp signalling system is designed to monitor and adjust to these traffic conditions to free up traffic.
Only at the height of peak hour traffic will cars be waiting longer than a few minutes than they did without the signals. Waiting times depend on the number of cars in the queue, and on how congested the motorway is.
Ramp signalling requires a small wait for a greater gain. Regulating flow on the on-ramp helps to relieve congestion and faster speeds can be reached on the motorway as a result.
Motorists on shorter trips should consider alternative routes to work through local roads, or travelling on public transport.
Most accidents on Auckland motorways happen during peak hours when traffic is stop-start, due to lapses in driver concentration and motorists travelling down crowded on-ramps vying for positions in traffic or trying to merge together.
Ramp signalling provides a smoother flow of traffic, minimising stop-start conditions by separating on-ramp traffic into streams of one or two vehicles.
Truck priority lanes allow trucks to bypass the ramp signal without stopping and losing momentum, especially when on-ramps are on an incline. The faster access also means that trucks can maintain a good speed onto the motorway, and will not slow down other vehicles. More reliable travel times for truck operators also ensures that commercial freight schedules can be maintained. There is a trucks only priority lane operating at Grafton Road southbound on-ramp.
Ramp signals look identical to regular traffic lights to avoid any confusion.
RUNNING A RED RAMP SIGNAL LIGHT HOLDS THE SAME PENALTY AS A REGULAR TRAFFIC LIGHT.
Ramp signals and vehicles using the priority lane will be monitored by police as part of their regular motorway patrols. This also applies to solo drivers attempting to skip queues by using the truck, bus and car-pool lanes. The New Zealand Transport Agency also uses CCTV monitoring to check traffic speeds at the on-ramp to ensure the system operates effectively.
Normal intersection traffic signals will be installed at the top of the Market Road off-ramp to assist traffic exiting the motorway. Market Road has been a difficult intersection to exit for both the north and southbound off-ramps and giving a light phase allowing free turning onto Market Road will significantly lessen queues back down the ramp. Transit and Auckland City Council will monitor the progress of this intersection closely to ensure the best results.
A large number of traffic movements take place along the stretch of SH1 between Hobson Street and Gillies Ave. Traffic from the Hobson Street on-ramp joins the motorway and merges with traffic from the north and northwest. Much of the traffic then changes lanes depending on the driver's desired destination. By spacing the number of cars joining the motorway at Hobson Street, ramp signals will help to improve traffic flow and create safer merging onto the motorway lanes.
This project aims to lessen congestion as a whole and therefore reduce fuel consumption and CO2 emissions overall. Specialists have advised that there will be some improvements in local air quality because of the project. Any measure that serves to relieve congestion on the Southern Motorway would lead to some improvements in air quality, both for local residents near the on-ramps and the wider region.
The ‘High Occupancy Vehicle’ lane is a priority lane to give high occupancy vehicles (HOVs – two or more people per car), trucks and buses faster access to the motorway.
Car-pool vehicles (two or more people per car) can use this lane to bypass the signals. The benefit of the lane is to move more people rather than more cars.
The priority lane for trucks, buses and car-pool vehicles will be operating soon at the Mt Wellington and South Eastern Highway northbound on-ramps. Motorcycles can also use the priority lanes, except at Grafton Road southbound on-ramp which is a trucks only priority lane.
So far, 26 ramp signals have been commissioned and are already operating successfully within the Central Motorway Junction, at each of the southbound ramps along the Southern Motorway between Hobson Street and East Tamaki, and at the Takanini and Papakura interchanges.
Data gathered has shown the following results since these portions of the system were commissioned:
In the busiest sections of the Southern Motorway where ramp signals have been commissioned in the southbound direction between the central city and the Ellerslie-Panmure, Mt Wellington and East Tamaki Interchanges, peak period traffic flows have been significantly improved with shortened periods of congestion. The motorway is carrying significantly more traffic during peak periods than before and speeds have increased.
Work has started to install ramp signals on all 15 on-ramps on the Northwestern Motorway at Newton Road, St Lukes/Western Springs, Waterview, Patiki Road, Rosebank Road, Te Atatu Road, Lincoln Road and Royal Road.
Improvements will also be made at a number of the existing off-ramps where traffic typically backs up during peak periods. The work will be completed later this year including several locations with priority lanes.