Posted traffic signs convey messages in words and/or symbols and are erected to regulate, warn, or guide road users. Traffic signs, however, are most effective when they fulfill a need, command attention, convey a clear and simple meaning. Command respect of road users, and give adequate time for proper response. Questions such as how well the existing sign systems are performing in terms of comprehension are discussed in this paper. Techniques used in evaluating and measuring drivers' comprehension of signs, standardization uniformity and differences among countries, and legislation and liabilities are also covered in this paper.
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