Boarding a public transport vehicle is always going to be a challenge unless the infrastructure has been provided to overcome the inherent problem of having to enable a moving vehicle to come close enough to a stationary structure that human beings can safely bridge the vertical and horizontal gaps between them. The bus stop illustrated here was designed as part of a research project called EXCALIBUR. In this project we sought to find out exactly what passengers with particular accessibility needs required, and then what a bus needed in order to meet those requirements. This of course meant finding out what bus drivers needed in order to deliver the bus safely and accessibly to the passengers. Inevitably this entailed a lot of compromises.
We could not achieve completely flat boarding. We could bring the vertical gap down to around 60mm and the horizontal gap to 25mm. Although all the wheelchair users we tested this with could board the bus in this position without the need for any further assistance (e.g. a ramp), we were aware that there would have been people for whom these gaps would be too much of a challenge. But to achieve even this meant a whole different concept of boarding and alighting.
To bring the bus that close to the kerb meant designing the approach path to the bus stop - which is what you see in the right hand photograph. The guiding line at the edge of the bus stop cage (the yellow dashed lines where the bus stops) was designed to guide the driver into the bus stop so that they could align the bus perfectly parallel and as close as possible to the kerb at a consistent position so that everyone would understand where to find the door (as you can see in the left hand image). You can see also that we moved the 'centre' line of the road a little (1m) so that cars could overtake the bus more easily when it was stopped at the bus stop. The design was a matter of understanding the needs of the most critical users and then translating these into the physical and mechanical requirements on the vehicle and infrastructure hardware, and then incorporating the mechanical and cognitive skills of the bus drivers in order to enable them to achieve a consistent performance. This was very popular with bus dribvers and passengers.
These photographs were taken in 2000 - almost 25 years ago. You don't see many of these bus stops arond today though. Why not?
There are several reasons. The simple ones are that this required a particular design of kerb that was under patent, and so very expensive. Coupled to this was the need to allow for the physics involved in slowing a bus down and aligning it to the kerb in one movement, which meant needing a lot of the expensive kerb - and associated kerb space. At that time (perhaps less so now) there was strong resistance to 'giving up' so much kerb space to a bus stop. Finally it was difficult to design - it required precise work and a lot of work with the travelling public, in particular with people with accessibility needs. The precision meant considering the drainage, the crossfall (slope across the footway), lighting, tactile paving, positioning of the shelter, accurate construction of the kerbs and so on. Too much effort. The net result was that it was easier to do what had been done before. The result is a much less accessible bus system than we might have had.
I recently attended a seminar in relation to the railway industry about 'good stepping' on and off trains. Trains have all the problems of buses when it comes to accessibility - a moving vehicle and hard infrastructure and the problem of horizontal and vertical gaps. In many ways it is even harder, even though they don't have to cope with the general public using their right of way. Trains travel at different speeds, have a different dynamic motion whilst in motion (roughly and simply-speaking, trains tend to sway sideways, whereas buses tend to sway vertically). So even though, unlike buses, they run on fixed tracks, they do move relative to the infrastructure around them. To protect infrastructure and trains, a variety of standards have been put in place over the years to set the gaps between the platform edge and the trains. At the seminar, it was shown that 7% of platforms in the UK actually comply with the standards. As with the bus stop, there is much more to this problem than the platform edge itself and it could cost rather more than HS2 to make all the platforms compliant.
To try and understand how to tackle this problem, the question has been shifted to look at what it is that needs to be achieved. This is just like the conversations and tests we ran with the potential passengers in the bus stops: let's ask the people who have the most critical concerns what they need and then work with the railway hardware, people and systems to try and achieve this. At the seminar this was introduced as 'good stepping'. The railway wants to see 'good stepping', but what exactly is that? This is where PEARL comes to the rescue!
We know that gap tolerances for people can be very small - even a 3mm vertical step can be a trip hazard. It is almost inconceivable (and certainly very expensive indeed) to design a working railway to that kind of tolerance. So the anaswer is to test a whole gamut of conditions with the whole range of people who have challenges to use the railway. This includes not only people who are disabled by the railway in terms of physical access, but also sensory and cognitive issues. And combinations of all of these. Then we need to bring the railway hardware in to see where that might be changed, including the people who operate it. This means not only the physical hardware but also the lighting, sounds, acoustics, smells, tactile sensations and more. Then we need to do this at different times of day or night (what happens when the sun is very bright and low in the sky, or the moon disappears behind a cloud?), different soundscapes and so on. Is that excessive? Not really. If you about to leave a train and you are greeted by the smell of your favourite burger, would that distract you from navigating the gap between the train and the platform and tripping over? Can the train operator see a passenger in dark clothes at the far end of the platform at night when they are standing in a shadow (and does the surface material of the platform make a difference to this?)?
All of these issues can be tackled in PEARL so that we could work with all relevant people to tackle these problems. By increasing the understanding we have of how people interact with the environment around them, we can find ways to create an accessible railway in reality, for the people, rather than to comply with the standards. What it means is making the standard a definition of 'good stepping' rather than some complicated formular about just vertical and horizontal gaps (which doesn't work anyway).
In this world what we need to study is how the brain responds to the actual multisensorial environment we live in. This is where PEARL is advancing both the science and the techniques of data collection and analysis so that we can study these "ecological interactions". You can't do that anywhere else at the moment. We will be explaining this at the World Mobility Congress in Barcelona (https://www.tomorrowmobility.com/agenda/?track=mobility).
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