| Summary |
(Li-Min Chen，2007.06
Feng Chia University
Because Changeable Message Sign (CMS) has been used in foreign countries for many years, and has good effects, currently a CMS hardware system on Taiwan freeways has been completely set. CMS is the most direct way for the drivers to get roadway information when compared to information of roadway radio or internet. The information of roadway radio is covering too wide areas to be directly useful for someone in short time. Besides, the information that served by the internet is obtained before a trip begins and can not provide in time roadway information. Therefore it is the important subject that CMS is used efficiently.
This research first depicts the effects of different display contents of CMS on route chosen by drivers, then, it is expected to become a reference to the managers who control the CMS system on freeways. The research designs many different scenarios about display contents of CMS, and collects stated preference information of drivers who take break in the rest areas on freeway. The data items include trip characteristics, route switching scenarios, and personal attributes. After completing the questionnaires, basic statistics are given first. Then binary Logistic regression is used to formulate six models. The first one is called ‘The model of having ever seen or heard of CMS or not’, second one named ‘The model of believing CMS or not’, the third ‘The model of being useful or not’, the fourth ‘The model of being satisfied with CMS or not’, The fifth ‘The model of switching route or not’, and the last one ‘The model of willing to purchase the PDA or not’. Except for ‘The model of switching route or not’, the remaining five dependent variables may have important implications on last dependent one, and these five models are also developed to reveal what factors will affect these five variables, in order to explore what really influence route changing.
The route changing model showed that when CMS displays more detailed contents, the proportion of route changing is higher. Useful CMS contents tend to attract more proportion. Satisfied CMS contents are easier to result in changing route. Other positive factors include using Freeway 3 as last route, listening to traffic information in radio, degree of traffic congestion. The most important factor is seeing actual congestion or not by one’s eyes. The model of being useful or not shows significant variables such as trip characteristics (e.g. the purpose of journeys, used to pre-planning the route or not, most used route, used to receiving real time information or not), willing to buy PDA or not, believing CMS content or not, personal characteristics (e.g. personality, occupation), experimental scenarios (e.g., in a situation when drivers see CMS, they can find congestion or not), being satisfied with CMS or not. The model of being satisfied with CMS or not indicates significant variables such as trip characteristics (e.g. meeting traffic congestion or not, used to pre-planning the route or not, listening to roadway radio or not, receiving other immediate information or not), believing CMS content or not, personal characteristics (e.g. personality), experimental scenarios (e.g. level for CMS content of detail, on weekdays or holidays, CMS is useful or not. In addition, some drivers, who answer relevant questions, think they can save approximately 28.97 minutes by changing route. Finally, route changing model is used to predict proportion of route changing, and this provides useful information for managers of freeways. |
