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We’ve heard various urban legends relating to traffic lights, particularly around whether the pedestrian crossing button actually makes a difference or if it’s just some kind of ‘placebo’ to keep you waiting for a break in traffic. TheJournal.ie spoke to traffic and road system managers and road safety advisers in Ireland to find out how those pedestrian lights really operate…

When a pedestrian presses a traffic light button to cross, does it influence the speed at which the lights change for them to cross?

In short: yes… and no.

Traffic lights systems and pedestrian crossings vary depending on their location and light changes are influenced by the flow of traffic, the number of pedestrians, the distance you have to cross, and if traffic or pedestrian sensors are involved.

Sensing your presence

Often in Ireland, pedestrian traffic lights will not be engaged until someone pushes that button. In particularly busy urban areas where high levels of pedestrians are expected to cross throughout the day, lights automatically include a pedestrian signal as part of the traffic light sequence.

Other crossings, though, have different light management systems involving sensors.

At some junctions, a sensor will actually note that a pedestrian is waiting to cross without them pushing any button, and will queue a light change for them in the lighting sequence to allow a break in traffic. (These can also cancel a request to cross if the person has walked away and is no longer waiting.)

Similarly, detectors can be put on traffic signal heads to detect gaps in traffic and give a pedestrian green light accordingly.

At other junctions, particularly on wider roads with a pedestrian ‘refuge’ in the middle, the little green man will automatically come up when traffic is stopped, allowing pedestrians to get halway across while waiting for the next section to change.

Countdown

In places of high traffic and high pedestrian volume, like Dublin’s Ha’penny Bridge, the pedestrian lights will show a countdown timer. The theory here is that having a countdown showing when the lights will change and allow the pedestrian to cross safely will discourage people from taking a chance to nip across the road.

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There are set guidelines for the length of time the pedestrian lights stay green in relation to the distance pedestrians have to cross. They may also stay green for longer if the sensors note a high volume of pedestrians walking in a particular direction, such as after a match or concert.

Some crossings have a special button (for example, ones marked with braille) for pedestrians who may need more time to cross, and they will facilitate a longer green light.The light changes also factor in how far cars travel from the stop position to where pedestrians are crossing.

Do the light changes adapt to different times of day?

In the case of those really busy urban areas where pedestrian light changes are automatically included in the traffic light sequence, yes. The auto-system only operates during the day (generally, 7am to 7pm). The other light systems will continue to adapt their sequencing to traffic and pedestrian volumes, which are typically much lower at night.

How are the locations of pedestrian crossings determined?

It all depends on the level of road use – for vehicles and pedestrians – but you can make a request to your local authority to consider new locations for pedestrian crossings. The introduction of a new crossing depends on safety factors, accident statistics, the difficulty for people getting across the road and the demand for a crossing (if there is high pedestrian footfall in the area, or a school nearby).

The type of crossing also varies depending on what best suits that situation: it could be (seriously) a zebra, toucan, pelican or puffin crossing. Picking between them depends on the speed and volume of traffic, the width of the road to cross, and what kind of delay pedestrians face when waiting to cross (the longer the delay, the more likely people are to chance a run across).

Local authorities will assess the requests for crossings and compile a shortlist of priority crossings. Actually introducing a new crossing though, depends on the available funding.

Safe crossing

Under the 1997 Road Traffic (Traffic and Parking) Regulations, pedestrians should not cross a road within 15 metres of a provided pedestrian crossing “except by the crossing”. The Rules of the Road carry guidelines for pedestrian road use, including how to safely cross the road:

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