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Bus Rapid Transit is Unsuitable

 

Why not Bus Rapid Transit?

BRT was chosen in Greater Wellington’s PTSS (in preference to light rail), but was never implemented, and Wellington’s golden mile bus route is still badly overloaded.

A BRT line has about one stop for every 3 regular bus stops. BRT and regular buses cannot both run on the golden mile, because there is no room for the faster BRT vehicles to overtake the slower buses. The only solution is another route but Wellington has few options; this dilemma is the primary reason why Wellington needs light rail.

The options for running BRT are:

• on a dedicated rapid transit corridor, such as the route FIT has proposed for light rail
• on a corridor shared with regular buses, which requires 4 lanes, so BRT vehicles can pass regular buses stopped at bus stops

In the city centre, once the golden mile is eliminated as too narrow, this leaves:

• Waterfront (Jervois and Waterloo Quays), two traffic lanes become dedicated rapid bus lanes; or
• The Terrace, using Courtenay Place, Taranaki St, Ghuznee St, The Terrace and Bowen St, removing parking so BRT vehicles have room to overtake regular buses; the route is less inconvenient than it seems as many buildings on Lambton Quay have public access lifts.

Unless all on-street parking is removed, in most places The Terrace is only 3 lanes wide and difficult to widen. These limitations make it unsuitable for BRT. It remains useful as a relief route to take some buses off the golden mile, either before light rail is built or if extra buses are wanted on the golden mile.

That leaves BRT on the waterfront only.

Understanding BRT means recognising several varieties.

The first is almost-BRT that operates more as an express bus service on regular streets. Neither the golden mile nor a Terrace route is suitable for an almost-BRT service: there is insufficient width for passing regular buses at bus stops.

Almost-BRT can be a cost-effective interim solution while a real rapid transit service is built, but is impractical in Wellington.

The second is Basic-BRT operating on a dedicated 2-lane corridor, such as FIT’s proposed light rail route. It would be limited to about 30–40 buses an hour. A double-articulated bus has a capacity of about 180 people, compared with about 470 on a much longer modern LRV. Hence the capacity of basic-BRT is about half that of a 2-lane light rail corridor and Wellington would soon run out of capacity.

At that point a large problem would appear: how to find space for light rail construction?

Basic-BRT is impractical as a long term solution in Wellington.

Full-BRT has similar capacity to light rail (say 10,000 passengers an hour), but in Wellington it would be very disruptive because of the width needed. Full-BRT has to run more frequently: say a LRV every two and a half minutes, but a bus every minute.

Full-BRT needs careful route-design: the ITDP ‘Gold’ or ‘Silver’ BRT Standard. This will need:

• Longer and wider stops, to accommodate longer buses in three-berth stops, and much wider to allow overtaking at stops. BRT stops in Brisbane are nearly twice the total width of Manners St.
• More grade-separation at busy junctions. FIT anticipates one or two grade-separated junctions for light rail, and more for more-frequent full-BRT.
• Much more costly tunnels than light rail, because of larger cross-sections and services too frequent for a single-lane tunnel.
• A more difficult route, because full-BRT would be impractical on many parts of the corridor due to lack of road space.
• Greater operating costs because full-BRT would need more drivers, the greatest single cost.

Full-BRT is very unlikely to be cost-effective in Wellington.

Glossary

BRT

Bus Rapid Transit

FIT

Fair Intelligent Transition

light rail

An urban mass rapid transit system, segregated from general traffic as much as possible, with wide spacing between stops and priority at intersections, fast enough to compete with private car travel

LRV

Light Rail Vehicle

PTSS

Public Transport Spine Study

Glossary →