Changes needed to stop Christchurch congestion as population grows

Thursday, 10 September 2020

It’s “just a question of time” until Christchurch's congestion looks like Auckland’s if nothing is done to get people out of cars, a transport expert says.

A recently released plan from the Greater Christchurch Partnership (GCP), which aims to get Cantabrians to reduce car use, paints a bleak picture of congestion if nothing changes.

Christchurch's population is forecast to grow to about 640,000 people by 2048. If travel patterns remain unchanged, that would lead to a 20 per cent increase in the number of car trips to and from the central city by 2038, and a 34 per cent increase by 2048.

A transport planner has suggested part of a busy Christchurch street should be blocked off from cars. Video first published in 2018.

The 2018 census found about 196,600 cars hit the tarmac daily for people driving to work across Christchurch, Selwyn and Waimakariri – representing 75 per cent of the workforce.

Brougham St currently carries about 50,000 cars daily.

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Transport planner Axel Downard-Wilke says in some transport corridors, a 10 per cent increase in traffic might make travel times twice or three times as long.

The most congested roads in Christchurch were Papanui and Main North roads heading north, Riccarton and Blenheim roads heading south-west, and Brougham St/State Highway 76. Brougham St alone carries about 50,000 cars daily.

Traffic count data from the city council from August showed Riccarton Rd near Matipo St carried about 25,600 vehicles on weekdays. Papanui Rd near Normans Rd averaged about 22,000 vehicles daily, June figures showed.

Currently, 87 per cent of household trips are in single-occupancy vehicles.

The heavy traffic seen on the right was heading north from Auckland on December 27. Now, for many, it's time for the return journey. (video published in January, 2020)

In comparison, just 2.5 per cent of peak hour travel used public transport. In 2019, about 13.5 million bus trips were taken.

The 2018 census showed more than 5 per cent of Christchurch workers mostly got to work by bike, while 9 per cent of students biked to school.

The number of cyclists increased rapidly since then as cycleways were built. A city council count showed the number of cyclists passing through seven central city locations during the morning peak increased from about 1400 in 2018 to about 2200 in 2020.

If traffic volumes were to increase by 34 per cent as forecast, it did not mean drive times wouldbe just a third longer.

Transport expert Axel Downard-Wilke said transport corridors would handle traffic increases with only slight increases in delay times up until a certain point, but once traffic went past that mark it would very quickly become congested, which would make a huge difference to travel times.

He said for some corridors, a 10 per cent increase in traffic might make travel times twice or three times as long.

Congestion on Cranford St during Thursday afternoon rush hour.

Downard-Wilke said it was “just a question of time' until Christchurch ended up with congestion issues like Auckland's if nothing was done.

The GCP plan says Christchurch currently had less congestion than other New Zealand cities, but action “is needed now' and must be sustained to avoid Christchurch “following in the footsteps of other major centres”, where work to get people out of cars only started “once congestion reached crisis point”.

The plan said New Zealand had a high car dependency because cities were structured in a way that prioritised them, encouraged people to keep using them and hid the true costs of doing so, and lacked good public or active transport alternatives.

It suggested three initiatives in the next three to six years, if funding was available: a $68 million cycleways package to fill in the “critical” gaps in the existing cycleways network, a $10m boost to encourage more public transport use, and up to $3m for promotions encouraging people to get out of their cars.

But there is no money for them yet – a GCP spokesman said the initiatives reflected unbudgeted projects relating to current work the councils were doing, that would be considered for funding.

He said this version of the plan was a 'starting point” on what could be done in the immediate future, and sat alongside other work.

There were plans to overhaul the public transport system which would include more frequent buses and rapid transit, possibly rail, to the north and southwest of the city. Authorities were working on three business cases for the proposed changes.

Downard-Wilke said the initiatives proposed were business as usual and “tinkering around the edges” and would not make a big difference.

He said it would be technically easy but politically hard to make mode shift happen and suggested two changes that would make a difference. The first was to decrease the speed limit to 30kmh across the wider urban area to encourage cycling, an approach that had proved successful in German cities in the late 1980s and early 1990s.

The other was to make driving less attractive by reducing the amount of low cost and highly available parking in the city.

This could be done by encouraging development on bare lots in the central city through changes to the rating system.

The GCP is made up of the Christchurch City Council, Selwyn and Waimakariri district council's, NZ Transport Agency, Canterbury DHB and Ngāi Tahu and aims to coordinate urban planning in the Greater Christchurch region.