Traffic hazard cured

Pedestrians will live more safely – thanks to researchers’ advice

For the last three or four years the traffic authorities have noticed an increase in the number of serious accidents between pedestrians and trams at tram crossing points.

“We brought in Chalmers Technical University and now we are applying their proposals at all tramway crossing”, says Peter Rydén, Head of Road Safety at the Traffic Department in Gothenberg.

“The negative trend, with more accidents, had to be stopped. That was both obvious and necessary in order to comply with rail safety regulations.

“It was necessary to understand how people think and react when they cross the tramway. We involved Chalmers because they have special competence in behavioural studies,” says Peter Rydén.

Seventeen tramway crossings were observed with consideration being given to different aspects of their design. Amongst the safety features examined were yellow line markings, signal arrangements and kerb-edge markings. Lighting, audible warnings, vehicle speed, cycle crossings and pedestrian refuge arrangements were also considered.

Habits depend on age
In addition, the researchers investigated how pedestrian behaviour is affected by age-related changes which are important in the traffic environment. Different age groups have different degrees of competence in dealing with traffic situations, both in their levels of attention and in their physical abilities. It was from the observations of older people’s behaviour that is was concluded that the design of tram crossings should follow five principles.

Avoid complexity: irrelevant and distracting features should be minimised. A solution is to divide up the crossings into stages and provide precisely the information that is necessary in each situation.

Maintain levels of attention and awareness: at each stage of the crossing process, pedestrians should receive clear and correct signals which sustain their attentiveness. These can take the form of lights or audible signals, preferably changing ones, which creates differences at each stage in the crossing process.

Consistency: use the same features to maintain attention levels at all crossings.

Clarity: the design features should relate to their purpose so that people will easily get to learn what they mean. For example, if a signal always has a particular meaning – such as stop or go – they effectively say what they mean and give a clear instruction. Use existing conventions: red means stop or forbidden, green means go or clear and yellow symbolises warning.

Eliminate mistakes: wrong actions can be divided broadly into three categories. Someone can intend to do the right thing but get it wrong subconsciously; they can misunderstand the situation but do the right thing in accordance with their interpretation; and they can deliberately break the rules. The first case is a result of distraction. The solution is to minimise occasions of distraction. The second case is, for example, when the pedestrian sees the green man for pedestrians crossing a car lane but does not notice that in front of the car lane is a tram track without signals, which has to be crossed first. The solution is to provide signals at each stage of the crossings. An example of the third case is when pedestrians know that the light is red and takes a chance and cross regardless. There is no solution to this kind of recklessless.

Clear markings
Chalmers’ main solution for all crossings was to provide yellow lines on the ground and one-metre high poles, black with yellow reflective strip near the top. These elements say to the pedestrian, “Now you are entering a new area.”

This is in accordance with Chalmers’ theory that it is advantageous to divide up crossings into different stages in order to increase attentiveness.

“The crossing at Liseberg is a good example of the new arrangements and how they should work. If a lot of people use the crossing we reinforce the measures with signs and signals. We have different levels depending on the number of pedestrians, the amount of car traffic, the speed of the trams, etc,” says Peter Rydén.

“Which signals are used is also important. There are yellow flashing signs in the town centre but they indicate not what they are warning of, which can confuse people. The traffic design office is therefore considering both how the light signals are used and where they are placed. One rule is that they should stand in line with the crossing so that so that people do not need to turn their heads to find the pole with the red light or the green man,” says Peter Rydén.

“Another important rule is that, regardless of what the crossing looks like, everyone, both drivers and pedestrians, give the tram priority.

“Following critical evaluation of the Chalmers proposals, the traffic office decided to alter all tram crossings. So far, 25 have been modified. We are continuing with the work until they have all been modified.”

What a pity the Brighton highway engineers take the subject less seriously. The studies were conducted by researches in the Human Factors – Engineering Product Development and Design Department of Chalmers technical college, Gothenberg, under the guidance of Anna-Lisa Osvalder, Docent, assisted by Maria Eriksson, Civil Engineer.


Article originally published in Göteborg Metro 10 February 2010.