This page is where you can find definitions and terms that are found on this website. If you don't understand a term you can find out what it means here.
This page will continue to be populated with information.
Use the find function (Ctrl + F) in your browser to quickly jump to a search term.
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
A
Above grade - see Grade / Grade Separated
Auxiliary Lane
Auxiliary lanes are lanes that are created at an on-ramp, and end at the next off ramp. It is ideal for areas where the next on-ramp is close to the last, or where high volumes of traffic enter and exit at both ramps. Currently there are six auxiliary lanes on the Auckland Motorway System; Esmonde to Northcote (NB), Khyber Pass to Gillies (NB/SB), St Marks to Market Road (SB), Greenlane to Market Road (NB) and Princess Street to Highbrook Interchange (NB & SB).
G
Grade / Grade Separated
Grade separation is where roads are at a certain level when intersecting with another. Grade denotes if it is above or below a certain point i.e. an interchange where the minor road travels below the motorway is below grade.
Above grade is when the crossing minor road travels over the top of the motorway or roadway. Interchanges like this are Greenlane and Esmonde Road or overbridges like Omahu Road.
Below grade is when the crossing minor road travels below the top of the motorway or roadway. Interchanges like this are Tristram Ave and Gillies Ave or underpasses like St Marks Road.
H
High Occupancy Vehicles
High occupancy vehicles (HOV's) are vehicles with more than one person in it (the driver). It is the technical name for carpooling. Ramp Signal priority lanes give HOV's that only have two people in them (including the driver) priority. HOV's and their rights in a transit lane are usually outlined in the vicinity of the lane.
I
Induced Congestion
Induced congestion means that congestion is caused in a location, by something that is not at that location. For example; if a section of motorway was widened from three to four lanes congestion would ease on that section, however as that traffic now moves freely and quickly, it arrives at the next bottleneck faster. Therefore creating congestion somewhere else, and usually worse.
This is one reason why the Newmarket Viaduct replacement project only offers a new lane in the southbound direction - and not in the northbound direction.
Interchange
An interchange on a motorway is an above grade or below grade intersection where motorway traffic going straight through does not have to stop. There are two types; one with no stopping (Spaghetti Junction) or one where all other traffic (that is not driving straight through on the motorway) must give way or stop (Esmonde Road Interchange). This is different to an intersection; where traffic may have to stop.
 |
The most common form of interchange in Auckland is the Diamond Interchange (left). This is where there is either an overbridge which goes over the motorway or the motorway goes over the road. Then there are usually two on-ramps and two off-ramps. The red circles note an intersection, where this is either controlled by give way, a round-about, stop or traffic lights.
Examples include the Northcote Road Interchange and Mt Wellington Interchange. |
|
Another kind of interchange is the completely grade separated interchange. This is where traffic does not have to stop and can freely move between minor or major roads (may have to stop for Ramp Signalling).
This style of interchange can take many forms. From simple ones like the South Eastern Arterial (SEART) in Mt Wellington or complex like CMJ (Spaghetti Junction) in central Auckland.
Usually this style of interchange will occur when there are heavy traffic volumes and the interchange is between other motorways or major roads. Currently there are only four of these on the Auckland Motorway system. Central Motorway Junction (Spaghetti Junction), the South Western to Southern Interchange, SH20a and SH20 on the South Western (Airport Interchange) and the South Eastern Arterial Interchange in Mt Wellington. |
Intersection
An intersection is an at grade meeting of two or more roads. Traffic is controlled with its movements between these roads either by give way, stop, traffic lights or round-about's. Intersections do not occur on motorways, as they must always be grade separated. But intersections do occur within interchanges like the above Diamond Interchange.
T
Traffic Volumes
|
|
VPD |
Busiest Section of motorway / road in New Zealand / Auckland |
Khyber Pass to Gillies Ave - Southern Motorway SH1 |
200,710 |
Busiest on-ramp |
Southern Motorway to North Western Motorway |
22,021 |
Busiest off-ramp |
Esmonde Road northbound off-ramp |
21,017 |
Auckland Harbour Bridge |
|
165,000 |
Newmarket Viaduct |
|
161,490 |
Victoria Viaduct |
|
105,512 |
St Marys Bay |
|
141,357 |
You can look at State Highway traffic volumes (nationwide) in this PDF here.
