Study And Evaluation On The Information's Usability Of Traffic Guide Signs

In recent years, as economic prosperity and development of highway's infrastructure construction, road density increases, road network has initially taken shape. Meanwhile, the growth of personal travel demand induces the rise of vehicles and drivers. The level of social's mobility becomes higher. However, the subsidiary facilities of highway have not kept pace with the development of infrastructure construction. As an important part of the subsidiary facilities, there are some problems in guide signs'designing and setting. There are not systemic norms and scientific guidelines on guide signs'continuous setting in the GB 5768-1999"Road Traffic Signs and Markings".The problems of guide signs as follows: the methods of guide signs'information selection can not meet the needs of the road net traffic system, locations, roads and route numbers are not clear, guide signs are lack of systematic and coherent in information dissemination. Signs do not meet the design standard and so on. In short, because of these problems, guide signs are in poor usability that failed to work. Road users are confused or disoriented with the guide system, resulting in delays, driving mistakes, even leading to undesirable consequences, such as traffic accidents. Those make roads and the surrounding road network system can not perform the function. This paper is based on the traffic construction technological projects of MOT (Ministry of Transportation):"The study on visibility and setting validity of road traffic signs". The paper focuses on studying the usability of guide signs information, aims at solving the problem of drivers'difficulties in wayfinding.Firstly, the paper reviews the course of guide signs'development. By introducing information theory, it expatiates on the information elements of guide signs. It makes a summary of the basal characteristics and functions of guide signs by comparing the guide signs, road map and referring to the theory of cartology. Then, information cognitive theory is used for analyzing the process of drivers' information cognizing. In allusion to the proper information type of guide signs, it quotes the concept of spatial cognition, cognitive maps and the mode of drivers'wayfinding to expatiate on the process of guide signs cognizing. And then, the method is used on the research of usability. By surveying the setting condition of guide signs, it researchs on the factors which impact its information's usability. Adopting the method of direct observation and advisory, it obtains experimental data on user behavior through the trip experimentation. These factors include the systemic and comprehensive of signs information, the matching of signs information to road function, the clarity of roads grade information, the continuity of signs information issue and the repetition of important information. According to the process of drivers'cognition and the type of information, it puts forward measures to enhance the usability of signs information and the general idea of guide signs'designing.Finally, according to the findings of foregoing paper, it establishes guide signs'evaluation system to evaluate their usability. Using the AHP (analytic hierarchy process) to determine the weights, adopting the method of fuzzy comprehensive evaluation based on the main's characteristics, it establishes the fuzzy comprehensive evaluation model. Selecting Beijing's provincial road Shun Ping Road as the evaluation examples, it researches and analyzes the Shun Ping Road on the spot by collecting photographs, video and other data. It builds a single-factor evaluation matrix to gain sub-targets for the evaluation matrix and then to gain the evaluation matrix of the overall goal. Through the fuzzy comprehensive evaluation, it finds the guide signs along Shun Ping Road are facing the followed problems: their information mainly is about local sits and regions, short of surrounding road network information, forenotice signs and affirmance signs in the larger intersection. Based on the evaluation results of the comparative analysis, it proposes targeted improvements.In the course of study, it applies the thinking of systems analysis, information theory, cognitive science and usability study. In the research methods, it focuses on the combination of qualitative analysis and quantitative calculation, the overall combination of detailed analysis and evaluation , theoretical analysis and application of integrated practice. In theory, it applies the concept of spatial cognition theory and cognitive maps innovatively. It makes the followed results of research:1. Expatiating the features and functions of guide signs comprehensively.2. Analyzing the type of guide signs'information and information cognition based on spatial and cognitive map.3. Introducing the research methods of guide signs availability, and designnig the real car driving test program;4. Establishing the guide signs'information availability fuzzy comprehensive evaluation model.