Hang Up the Phone and Get Online: Measuring the Effectiveness of Web-Based Surveys in Transportation

Surveying is a common tool used to collect public opinions, attitudes, and behaviors in transportation. Because of the high importance of obtaining reliable results, it is imperative to choose a proper survey method and a reasonable sampling plan. For the past 40 years, telephone surveys with an RDD (Random Digit Dialing) sampling method have been used to conduct transportation surveys. With the advent of the Internet and its continued expansion to nearly all members of the population, web-based surveys have become a potentially superior method of collecting survey responses. This paper presents a case study and compares the results of two surveys conducted on the same transportation related topic in consecutive years. The 2010 survey was conducted by telephone survey using an RDD sampling method and the 2011 survey was conducted as a web-based survey using a multi-method sampling approach. A Chi-squared test of the given probabilities was conducted to test which sample outcome is more closely related to the distribution of the population. Additionally, several questions are compared between the two surveys to explore differences in responses and possible reasons. The results of this study confirm that as technology progresses and the Internet becomes a main mode of communication, the web-based survey is a tool that is just as good as or better than traditional telephone surveys using RDD to conduct survey research in transportation.