The Humble Zebra

In the late 1940′s, the UK Ministry of Transport commissioned research (undertaken by the Transport Research Laboratory in Wokingham) involving experiments with different road markings at pedestrian crossings to improve visibility. They tested blue and yellow stripes and even red and white stripes. Ultimately the combination of black and white stripes was found to have the greatest visual impact. Pedestrians were found to be much clearer to drivers when set against the black and white background. In 1951 the zebra crossing was given legal status. The first zebra crossing, of the form that we would now recognise (see below), was officially opened in Slough, Berkshire, on October 31, 1951.

ZebraIn the UK zebra crossings are marked with Belisha beacons. These are the familiar flashing amber globes on black and white posts placed on each side of the road. The beacons were named after Leslie Hore-Belisha, the Minister of Transport, who first introduced them in 1934. The early Belisha beacons did not flash. This was an innovation brought in to make zebra crossings more visible to drivers operating in bad weather and at night.

Pedestrian crossings were originally marked by beacons and parallel rows of studs. The all important stripes were added for visibility some 15 years later. Jim Callaghan, later to become Prime Minister, is said to have been the first person to comment on the crossing’s resemblance to a zebra.

Despite the initial success of zebra crossings, by 1960 more than 500 people died on them in the UK in just six months. This led to the introduction of the Panda crossing – a signal controlled pedestrian crossing with traffic lights – in 1962.

On November 1st 2011 The Economist reported on “The curious demise of the zebra crossing.”

The black-and-white striped road crossings turned 60 this week, and the daily press duly wheeled out the expected shots of the Abbey Road crossing made famous by the Beatles, but also the unexpected statistic that 1,000 of the crossings have vanished in the last five years.”

It is said that, without other measures to force drivers to reduce speeds, the humble zebra provides insufficient protection for pedestrians. With more than 100 injuries a year on zebra crossings, local authorities are installing pedestrian crossings with traffic lights instead.

In the Mail Online on 30 October 2011 there was an article by Kerry McQueeney. The headline read:

Extinction of the zebra: 1,000 crossings disappear as hi-tech replacements and increased death toll signal end of an era

This article points out that zebra crossings were introduced to tackle mounting road deaths in the late-1940s and early 1950’s. But apparently the death toll on such crossings has doubled in the last four years.  According to the Mail, five people were killed on zebra crossings in the year prior to the publication of their article and 144 people were seriously injured. This compared to just three people who died in 2006. Some people have argued that one reason for the decline in safety is that in Britain fines for a motorist prosecuted for not stopping at a crossing are relatively modest when compared with many other countries.

The selection of appropriate forms of pedestrian crossing for each situation is no trivial matter. Zebra crossings  are relatively low in cost and pedestrians do not have to wait for the traffic lights to change in their favour before crossing. The disadvantage of zebras is that some drivers are reluctant to stop for pedestrians. In particular,  if a zebra crossing is not used frequently by pedestrians, drivers tend to forget it is there, which can lead to accidents. Furthermore, it is hard for pedestrians with visual impairments to use zebras and they can cause significant delays to vehicles when pedestrian flows are high.

PelicanThere are several alternatives to the zebra which are available. Pelican crossings (see image left) with signal control tend to be used on roads which have high traffic volumes, high traffic approach speeds or very high pedestrian flows (e.g. near stations and schools). The advantage to this type of crossing is that drivers have a clear instruction – via the red signal – to stop. Visually impaired people benefit from the ‘beep’ that sounds when the green man is showing. The pelican supposedly minimises vehicle delays by making pedestrians wait and cross in a group, rather than one by one. One of the disadvantages of pelicans is that the traffic lights and railings may be considered visually intrusive in certain contexts. Generally, residents do not want a crossing directly outside their home which causes planners problems in finding suitable locations. Also, at pelicans pedestrians will often push the button and then either cross in a gap in traffic, or continue walking down the road. The sequence of lights will continue, causing unnecessary delay to traffic, when nobody is crossing.

Puffin crossings are a variation on a Pelican crossing. The lights controlling the pedestrians are on the near side of the road, rather than on the opposite side. This allows the pedestrian to monitor passing traffic, while waiting for the signal to cross. Having the lights closer to the user assists people with visual impairments and the elderly. Some push-button units are also fitted with a tactile knob under the unit which rotates when the user may cross. This feature is to assist visually impaired people. Puffins also utilise infra-red sensors which detect the presence of pedestrians waiting at the crossing, and as they are crossing the road. The sensors detect that there is a pedestrian waiting, once the the button is pressed. But, if the pedestrian moves off, the sequence is cancelled, and traffic continues unhindered. Puffins are also able to detect pedestrian movement in the centre of the road. If there are slow moving pedestrians still crossing, the pedestrian time is increased and the traffic signal remains on red. The Toucan crossing is basically the same as a Puffin crossing, but is wider to allow cyclists and pedestrians to cross together. They are used on designated cycle routes which cross main roads.

Another low cost option available to highway authorities is to introduce a traffic island and pedestrian refuge. A traffic island situated in the centre of a road (see below) helps reduce vehicle speeds and may prevent over-taking. A gap in the middle of the island is called a refuge. The refuge/island allows pedestrians to cross half the road at a time. One disadvantage is that the islands are generally not suitable for large groups of pedestrians (e.g. school children). The islands can also cause problems for cyclists and wide vehicles. In addition they reduce space available for on-street parking and may be considered visually intrusive in some contexts.

Island & Refuge

The British zebra crossing acquired international fame when The Beatles used one on the cover of their 1969 album Abbey Road. Believe it or not this iconic crossing in St John’s Wood, London, was recently granted a Grade II listing to preserve the site. Long live the humble zebra !

About djtplan

Independent Transport Planner
This entry was posted in Pedestrian Planning, Transport Planning, Uncategorized. Bookmark the permalink.

One Response to The Humble Zebra

  1. Pingback: Você sabia que a faixa de pedestre é resultado de pesquisas científicas? - Jalopnik Brasil

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