Discussion
This work deals with the situation when elderly and disabled people enter and leave cars. The aim was to define requirements of entrances of cars used in the taxi service. For taxis, with their rather short journeys, it is essential that the passengers can enter and leave the car quickly, easily and comfortably. That will make the taxi service more attractive for the elderly and disabled passengers, and will ease the drivers’ situation when assisting the passengers. More than 90% of the special transportation service journeys are carried out by taxis. There were many difficult movements for the subjects
during entering and leaving; still it went quite well at a suitable shaped entrance with suitable handles to support on. Some subjects needed an assistant to help them to lift their feet in or out, or to transfer their body. The assistant needed extra space at the doorway in order to achieve a good working posture when helping the subject. Some wheelchair users used a transfer-board to make the transferring action easier, as it works as a bridge between the wheelchair and the seat. The person could then transfer little by little and rest in between. It is essential that the seat and wheelchair have about the same sitting heights, otherwise the transfer-board will have an incline making transferring more difficult. The subjects evaluated the different shapes of the doorway. Sometimes it was difficult for them to choose between ‘difficult’ and ‘impossible’. ‘Impossible’ means in this case ‘I do not want to do this’ and relates to how much effort the person is willing to exert in order to be able to travel by taxi. In a real case the alternative may be to stay at home. The evaluation of the trials is based on the subjects’ opinions, as well as the observers’ opinions when watching the trials and the video-films and on timing. That gives a good basis for stating requirements. The requirements are based on the results of the trials. They are influenced by the fact that only some certain basic dimensions and increments could be obtained in the mock-up and that a limited number of subjects has tried a limited number of the possible combinations of the entrance dimensions. In addition to that, the elements in the entrance interact with each other. The stated requirements have two values, minimum/maximum and comfortable. It was difficult to find the exact limits between them. The stated requirements are valid for sedan type cars where the passenger enters through the doorway and sits down on to the seat in the same operation. The requirements are not valid for other types of car where the passenger first enters through the doorway and then finds a seat and sits down, or where the seat height is much higher. The trials were carried out with the mock-up car at street level, and only one seat height was tried. The seat height influences the height necessary for the top part of the door frame. If there had been a pavement, the effective seat height and the height of the upper part of the door frame would have been lower in relation to the subject. A lower seat would have made it more difficult for ambulant disabled to sit down and rise, and a lower door frame would cause a higher risk of hitting their heads on the edge of the roof. Wheelchair users are often dependent on having about the same heights on the wheelchair seat and the other seat when transferring and, thus, a lower seat would have made it more difficult. In a case where the car is parked at a kerb, the doorway and seat heights would probably have to be higher to provide good conditions for disabled persons when entering and leaving. Ambulant disabled and wheelchair-bound subjects showed a similar way of entering and leaving the car. Most of them sat down or transferred their body on to the seat first and then they lifted in their feet. The end posture was sitting in the seat for both categories of subjects, and the swivelling and lifting of their feet in or out was carried out in a similar way. Therefore, very much the same entrance dimensions are needed both for ambulant disabled and wheelchair users. The subjects in this study were rather seriously disabled. All of them were entitled to travel with the special transportation service. They showed a similar way of entering and leaving the car as the subjects in the studies carried out by Brattglrd et al (1973) and the Institute for Consumer Ergonomics (1985). All of the subjects used handholds and handles in a similar way. This study and the buck-trials of the Institute for Consumer Ergonomics (1985) show very similar results. There are however three interesting differences: sill height above the ground, where the subjects in this study accepted 390 mm compared to 270 mm in the buck trials; distance from the front door-post to the seat front edge, 300 or 350 mm in this study compared to 440 mm; distance between the front door-post and the back door-post, 800 or 900 mm in this study compared to 980 mm. The differences of the sill heights acceptable for the subjects may be dependent on the different floor heights of the mock-up and the car-buck, and that the seat height in the mock-up was zather high. The differences of the acceptable distances from the front door-post to the seat and to the back door-post may, to some extent, be explained by different trial procedures. The Institute for Consumer Ergonomics (1985) moved the back door-post forward in steps making it more difficult to reach the seat, while in this study the back door-post and the seat were moved forward. There are complicated interrelationships between the variables. Further more it is difficult to state what is acceptable. The subjects in this study were used to travel by taxi and some taxi cars are even more difficult to enter and leave. A comparison of the dimensions of the entrances insome common makes of car used for taxi service with the dimensions needed for people with mobility impairment to get into and out of a car, shows that the required minimum dimensions are met for the front doorway, except those of the height from the ground to the edge of the roof. The dimensions for the comfortable range are not met and the back doorways do not fulfil the required dimensions. It is important that the taxi companies use cars that, as far as possible, meet the requirements stated as being in the comfortable range whenever possible. Car manufacturers can use these results when developing new cars suitable for elderly and disabled people.