A few weeks ago there was an unfortunate trial of a bike facility design known as “advisory” bike lanes. Advisory lanes, sometimes called “suggested” bike lanes are common in the Germany, Switzerland, Denmark, Netherlands, Belgium and increasingly North America. There are some good examples from NL in this guest post by Andre de Graaf .
Here’s how advisory lanes work. On narrow streets the centre line is removed leaving a 2-way combined lane ranging between about 4-5m. Wide bike lanes (1.5-2m) are located on both sides. When motorists pass a cyclist they take a more central position in the street. When cars pass each other they do so slowly, crossing the dashed cyle lanes. In the rare occasion when two cars pass when there’s a person on a bike nearby, the car driver slows down until it’s safe to pass. Advisory lanes reinforce an established etiquette in European cities – give way to cyclists, slower vehicle speeds, and sharing road space. Like conventional bike lanes they also communicate the likelihood of people cycling on the street.
Advisory bike lanes are used in low speed, low volume settings where there is not enough width for formal or segregated bicycle facilities. The Dutch CROW manual recommends their use on streets with less than 4,000 vehicles a day. When used in the Netherlands they are strictly implemented in conjunction with lower speed limits and traffic calming measures. On rural roads their use is limited to local roads with no more than 60 kph speed limits. Rural roads in the Netherlands are either 60kph or 80kph and they also have comprehensive speeding enforcement making their analogy to New Zealand tenuous.
This design is being experimented in urban settings in many emerging bike-friendly cities. They are often seen as a hopeful solution to constrained street corridors and limited budgets. The City of Minneapolis (Copenhagenize Bike Friendly City #18, US Bike Friendly City #1, 2015) has recently been using the design and Portland, Oregon has plans to use them on 42 miles of new bikeways.
The North American versions seem somewhat awkward as the streets don’t have the same scale or context as European streets. That said, the Minneapolis project above has had impressive safety results.
The fizzer of the NZTA trial was a unfortunate setback as I see advisory lanes being a useful tool in urban settings to expand bike access coverage into wider residential catchments where vehicle volumes are low and speeds are slow enough for sharing. That said, I have been struggling to think of a place where they might be usefully deployed, until recently.
In Mangere Bridge there is an amazing waterfront street Kiwi Esplanade which I recently discovered.
The street serves as prime cycling route in its own right, but also as it connects up to Ambury Farm, making it a useful cycling link. On my last visit the roadie-type cyclists were using the street, and the more casual cyclists were bumbling along on the windy 1.4m footpath. The later arrangement doesn’t work well as there are also a lot of people walking.
While Mangere Bridge consists of a well connected grid, most streets are ginormously overscaled complete with motorway barriers, painted medians and other armature of the Manukau era.
One thing that makes Kiwi Esplanade viable for sharing is that is mostly insignificant from a wider street network perspective. There are better alternatives to get around the place, to the town centre, and the motorway. The street cross section currently reflects this as well. The street is very narrow ranging between 6m – 9m, and there are also speed humps in some sections.
I could see this being a good street where sharing the carriageway with advisory lanes could work. Below is a mock-up of a segment with advisory lanes and dimensions (streetview).
In addition to a speed limit change to 30kph, it would also require traffic calming treatments at intersections (see below for example). This could be achieved by favouring the network alternatives and slowing through traffic (along Kiwi Esplanade) with chokers and/or raised crossings.
At some point advisory bike lanes will become a useful tool in expanding the core cycle network beyond the main arterials and in conjunction with enabling slow speed, bike-friendly neighbourhoods. At this point I do wonder if their experimentation is a bit cart-before-the-horse.