Is Human Factors Ready for the Automobile?

Abstract

ABSPRACTThis paper examines the role of human factors in the design of autmbiles. A prime objective of our human factors profession is to improve the design of machines, thereby benefiting users in terms of comfort, convenience, operating speeds, accuracy and safety. Although the purpose of an automotive human factors program may be to achieve all of these objectives by improving vehicle design, the mechanisms for doing so probably cannot be discovered by focusing research attention on the vehicle element of the driver/vehicle/road system. In fact, the nonvehicle parts of this system are probably by far the most productive topics for future human factors research. The abilities of drivers, their limitations, and the tasks imposed upon them by the traffic environment should indicate how vehicles can be designed to best serve the drivers' needs.After twenty years of automtive study, the human factors research c o m i t y is surprisingly unprepared to participate in vehicle design projects. The vehicle has too often ended up the subject of human factors research and researchers have been faced with the job of finding ways to improve the vehicle or a vehicle compnent without knowing enough about the intended user or the job the user must perform. The research community has only rudimentary and often incomplete background information about drivers and their traffic environments. The meager data base which is available suggests that traditional empirical approaches for evaluating machine design may be too clrmbersome and time consuming to keep pace with other aspects of automotive technological evolution. The tradition of developing alternative versions of hardware and subjecting the alternatives to human performance tests may not be a viable methodology in the future. A look at the total automotive system shows why.Drivers in the United States accumulate about 1.6 trillion miles of travel each year. During the year, a typical driver makes over 60,000 discrete control operations not counting steering wheel movements. The imensity of the automotive system means that very small driver error rates in control usage quickly accumulate into large nlrmbers of error events nationwide. The best information available suggests that the U. S. driving public uses their turn signals 854 billion times a year. This amounts to a nationwide rate of 27,000 times per second. If the generic human error rate in using the turn signal can assumed to be one error per 1000 operations, then turn signal errors are being made at the rate of 27 per second nationwide.Human factors research has tended to avoid error rate as a principal measure of performance in research programs. The reason becomes apparent when the n e r of tests which must be conducted to detect changes in rare events such as turn signal errors is computed. If two turn signal designs are to be compared and the researcher wants to be able to detect with 95 percent certainty (at the 5% level of significance) that the error rate has been cut in half by one of the two designs, then a l...