Many are excluded from active participation in society because of doorways that are too narrow for wheelchairs; steps that cannot be mounted leading to buildings, buses, trains and aircraft; telephones and light switches that cannot be reached; and sanitary facilities that cannot be used. Similarly they can be excluded by communication barriers, for example oral communication which ignores the needs of the hearing impaired and written information which ignores the needs of the visually impaired. Such barriers are the result of ignorance and lack of concern; they exist despite the fact that most of them could be avoided by inexpensive yet careful planning. Although some countries have enacted legislation and launched campaigns of public education to eliminate such obstacles, the problem remains a crucial one.