Decongestion charges can fix motorway induced woes

Christchurch needs new pricing tools and new transport projects to prevent repeating Auckland’s transport mistakes.

A meeting discussing the history and impact of Christchurch’s northern arterial motorway was organised by a recently formed voluntary group -the CHAT (Canterbury Housing and Transport) Club.

Many in the crowd were local residents angry that the motorway had been imposed on them without their consent. They were angry that they will incur the costs -in the form of clogged up roads and increased noise, vibration, air pollution…. While getting few of the benefits. Some speakers wanted to express that anger to any official or politician they could. There were several speakers who who were belligerent, bitter and not in a mood to be constructive.

I thought Councillor Sara Templeton asked the right question -what can be done -most speakers articulated some sort of rapid or mass transit solution.

Axel Wilke one of the CHAT Club organisers also said that we cannot build ourselves out of the problem -meaning faster/wider motorways funnelling traffic into an existing road network will not help because induced demand means the roads will quickly congest up.

Interestingly, Sara contradicted Axel by saying we can build ourselves out of the problem -just not by building roads. Meaning building alternative infrastructure -cycleways, rapid transit etc. Then induced demand works to help solve the problem -i.e. the more people cycle, the safer people feel leading to more cyclists. The more people who use rapid transit, due to economies of scale, the more economically feasible a rapid transit network becomes.

The northern arterial motorway will deliver connectedness benefits to people making journey’s from or to places in the northern part of Greater Christchurch. The difficulty is that this group receive the benefits whilst the costs are being borne by the good folk in St Albans (which they are angry about). The costs are;

  1. Increased pollution -air, sound, vibration. The transition to electric vehicles will mean over time these costs decrease.
  2. Increased congestion -it is predicted that vehicle numbers on Cranford street will increase by 30%. This will divide neighbourhoods and make roads more dangerous for walkers and cyclists. Electric vehicles will not solve this problem for spatial economic reasons nor will autonomous cars for similar reasons.

One solution to reduce the damage to St Albans from excessive congestion and help fund alternative transport infrastructure solutions would be to impose a charge on motorists entering St Albans from the motorway. The charge being set to the level that keeps Cranford Street free flowing.

This option will encourage traffic to split at QE2 Drive (SH74) or further back at the Western Belfast Bypass. These options will encourage traffic to go around the city not through it. The charge will also induce some car traffic to switch to public transport either completely or using park-and-ride schemes.

Usually single location road tolls, such as a charge for leaving/entering the Northern Motorway at Cranford Street would be considered inefficient, because it discourages the use of the high capacity road whilst clogging up other lower capacity roads that are not tolled. But the alternative roads will be significantly less attractive as they are longer and slower speeds (60km/hr versus 100km/hr) -such as Main North road going through Belfast or Marshlands road -so there will be no easy way to avoid the charge for drivers wanting to travel through the centre of the city.

In the past tolling roads had significant transaction costs -it required vehicles to physically stop at toll booths. Technology means there are alternatives which have much lower costs. Christchurch should investigate these options.

In the medium to long term a technological solution to replace fuel taxes and older road user charging devices will be found. The increasing uptake of electric vehicles nationally means a new revenue gathering system to replace fuel taxes is needed.

Toll roads already exist in New Zealand. There are some around Tauranga and one north of Auckland. Typically they charge about $2 for a light vehicle. If this charge was on Cranford Street it could generate about $40,000 a day or over $10 million a year (based on current daily use numbers multiplied by 250 days a year i.e. weekends are free).

Imposing a congestion price solves Axel’s problem that building roads to relieve congestion is futile because it induces further demand that causes the congestion to return. Cranford St could be prevented from congesting up by charging motorists. This might mitigate much of the anger in the St Albans community.

Eventually a more general road pricing solution covering both the northern and southern motorways -perhaps the whole city will be the best long-term solution. But Cranford street could be a good place to start this process.

One difficulty with congestion pricing the northern arterial is that the switch to public transport will be limited because residents in Waimakariri already can save significant amounts of money by taking public transport -for instance $7,500 a year by switching to busing from Rangiora -commuters are not using this option because it is too slow. So a congestion price scheme would need to be tied with a scheme to provide rapid transit alternatives. Politically it would also be difficult to impose congestion road pricing if there is not good public transport options.

Commuter trains from Rangiora and Rolleston with park and ride schemes would be a huge benefit for Greater Christchurch. These trains should go to a rebuilt Moorhouse Avenue train station. In my opinion the revenue generated from congestion pricing should go towards these infrastructures.

I also think a bus rapid transit corridor up Manchester/Buchan streets starting at Brougham St and ending on Edgeware Road would help -because it would connect a new Moorhouse Ave train station with the Bus exchange (a tunnel or bridge connecting Buchan St with Manchester St would also be necessary). The link between the Moorhouse Ave train station and the Bus Exchange could be the start of a congestion free rapid transit network. The Manchester/Buchan street bus route also creates a north/south rapid transit corridor that could quickly access the free flowing motorway system (because it is congestion priced) to provide rapid transit services to places away from the rail rapid transit corridor. A fuller explanation can be read in my paper -Greater transport choice can help revive Christchurch.

This proposed linear bus spine would have similarities to the Dublin bus system. Although it would not completely replace Christchurch’s hub model -especially the high frequency bus corridors between the city centre and Riccarton or Papanui. In the future these bus corridors may be converted light rail. These high frequency corridors also bisect the rail tracks at Riccarton/Mona Vale and Papanui/Northlands Mall, so combined rapid transit stations at these locations are further opportunities to expand the rapid transit network.

Congestion pricing could help turn Christchurch’s ‘problem’ infrastructures -the motorway system -into ‘beneficial’ infrastructures. It could be the catalyst that provides the city with a much more balanced multimodal transport network.

The congestion in Cranford Street that will come from the Northern Arterial Motorway is just one specific example of the transport difficulties that Christchurch will experience in the coming decades. A ‘do nothing’ approach risks Christchurch repeating Auckland’s mistakes of not investing in a rapid transit system in the 70s, 80s and 90s leading to congestion and a large infrastructure deficit in recent decades.

Population growth over the next three decades is predicted to add another 150,000 people to Greater Christchurch’s population. This translates to 135,000 more cars and 60,000 more houses (based on Canterbury’s car ownership rate being 900 cars per 1000 people and a home occupancy rate of 2.5 people per house in Canterbury).

It could be much more. Recently Greater Christchurch has grown by 10,000 people a year, at a growth rate of over 2%. If that continued for thirty years then there would be an extra 300,000 people living in the city.

Christchurch’s existing road network, especially the arterial roads going through the centre of the city can not get any bigger. So more vehicles means less space on the roads. This is why mechanisms need to be implemented to encourage people to use more spatially efficient modes of travel.

The draft Canterbury Regional Public Transport Plan is open for submissions.

The public can comment on the plan until October 14. You can submit here or at the ECan offices in Christchurch and Timaru.

I will be submitting this proposal to ECan. What do you want to submit on?



A collection of essays about cities, housing, land, the built environment, and transport which collectively make the case for New Zealand to implement a wide ranging urbanisation project

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Brendon Harre

When cities erect barriers that make it harder to build houses, I think this is landowners lobbying lawmakers so they can earn without toil.