needs is made by means of analysis of the gamut of possible conflicts taking into account the relative incidence with which certain conflicts lead to accident. A basic signal set is defined following this analysis. A survey has been made of current regulations in Australia and elsewhere and a survey of the signals of 29 of the ,aaost popular vehicles established the nature of current practices in Australia. Comments and recommendations are made on the form and manner of specification of requirements for vehicle signals. An extensive discussion on possible improvements to the signal system follows. This is based primarily on the conflict analysis, current practices and information on the literature but is supported in part by some field observations which are reported in the appendices. Photometric requirements for signals are derived from the work of Fisher and Cole and the conflict analysis. Detailed recommendations are made for intensity and luminance requirements for all classes of signals. A total of 44 recommendations are made for the improvement of the vehicle and system.
9.4.19 (74524) Cooper, M.B. Design and evaluation of flashing light codes for telecommunications equipment. Post Office Research Centre, Martlesham Heath, Ipswich. Post Office Telecommunications Research Department Report No 636, 1977, 20 pp.
were: Calling: 200 ms on/200 ms off, etc. Held: 60 ms on/600 ms off, etc. Active: 940 ms on/60 ms off, etc. Engaged: continuously on. Free: continuously off. 9.4.20 (74529)
Teichner, W.H., Christ, R.E., and Corso, G.M. Colour research for visual displays. Jun 1977, 130 pp; abstr in Government Reports Announcements (Report No AD-A043 609 7GA). The report presents the results of three complex multiple task experiments intended to compare the effectiveness of colour coding in visual displays against coding by achromatic letters, digits and shapes. The results of these three experiments are then integrated with previously reported research to provide a comprehensive assessment of the potential advantages and disadvantages of colour coding. 9.4.21 (74532)
Hoffmann, E.R., and MacDonald, W.A. A comparison of stack and diagrammatic advance direction signs. Australian Road Research, Dec 1977, 7.4, 2 1 - 2 6 . Two laboratory experiments compared stack, offset-stack and diagrammatic advance direction signs in terms of threshold visual angle (Experiment 1) and response time and errors (Experiment 2). Signs displayed two, three or five possible exit directions, so there were three levels of complexity within each sign type. Results showed that stack signs can be smaller than offset-stack and diagrammatic signs for the same level of legibility; response time to two direction offset-stack signs was significantly less than to other signs; neither sign type nor complexity was related to number of errors, which was very low.
A study was conducted to produce recommendations for flashing light codes for a new telecommunications system. No guide to the design of flash codes was found in the literature, although one author listed detectability, discriminability and the use of existing associations as important aspects of any set codes. Associations between flash codes and the states to be 9.4.22 (74537) indicated (Calling, Held, Active, Hartley, J., Davies, L., and Burnhill, P. Engaged and Free) were assessed by Alternatives in the typographic design considering existing practice and by means of two experiments. The of questionnaires. Journal o f Occupational Psychology, 1977, 50.4, 2 9 9 - 3 0 4 . experiments suggested a link between codes with rhythms resembling those Four layouts for a questionnaire were of telephone tones and the states designed and a comparison made between indicated by those tones. Two code them in terms of cost of production, sets devised in the Research Department ease of completion, and speed of data and a third suggested by a manufacturing retrieval and coding. The results indicated company were assessed subjectively in no significant differences in terms of terms of speed and accuracy of speed of completion and coding, but recognition. Estimates were also made that cost-benefits would emerge for of the effects on recognisiton times of different layouts, particularly if the change from synchronised to traditional printing methods of independent starting. The evidence for production were employed. and against each of the code sets was considered, resulting in a recommendation to use the Research Department code 9.4.23 (74538) set derived from consideration of Hartley, J. recognition time and ease of Designing instructional text. Kogan discrimination. The recommended codes Page, London, 1978, 125 pp.
This b o o k gives guidelines for the writers of instructional materials based upon current practice - particularly as employed by typographers - and upon a critical reading of relevant research. The main concern of this book is with clarity in the presentation of textual information and related graphic aids. The b o o k starts with some basic points about typographic planning. The aim here is to assist writers, typographers and printers and to suggest that some typographic practices may actually hinder rather than help the users of text. Chapter 5 demonstrates this point specifically by providing examples of instructional text, first in their original state and then in revised versions, following the points made earlier. The second part of the book is concerned with more general issues, such as the functions of illustrations, tabular materials and the like, and with various alternatives to conventional prose for instructional text. A third section discusses more specialised issues - lecture handouts, bibliographies, indexes and reference material. The book concludes with a discussion of the problems of evaluating instructional text and a brief annotated bibliography, plus a note on national and international standards and a list of centres of relevant research in the UK. Each chapter is followed by a summary of the main points covered and a checklist for the evaluation of typographic decision-making in instructional materials is given at the back of the book. The b o o k is illustrated throughout with examples of printed texts and tables. 9.4.24 (74541) Szlicheineki, K.P. Telling people how things work. Paper presented at the Ergonomics Society Meeting on Consumer Ergonomics, December 19, 1977, 13 pp. This paper presents a few ideas about the instructions which go with consumer goods and services and which enable people to take advantage of them. Although it is the aim of ergonomists to make the operation of machines and systems as self-evident as possible, instructions usually have to be provided since the cost of completely self-explanatory apparatus may be excessive or its complexity may make it impracticable. Instruction design must be considered as part of overall system design and the need to write simple instructions may influence the design of the equipment or system to be described. Instructions must provide information as it is required; this means that events should be described in the order in which they occur. When a person meets a novel piece of apparatus he will have expectations
Applied Ergonomics December 1978
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