𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Non-commitment bias in public opinion on transit usage

✍ Scribed by Arun Chatterjee; Frederick J. Wegmann; Michael Andrew McAdams


Book ID
104643469
Publisher
Springer US
Year
1983
Tongue
English
Weight
561 KB
Volume
11
Category
Article
ISSN
0049-4488

No coin nor oath required. For personal study only.

✦ Synopsis


Estimation of ridership on a new transit system in an area where no comparable service existed before is a difficult task of transit planning. Traditional modal split models cannot be used in these cases, because no data or basis for developing a new model or adjusting a "borrowed" model are available. One of the techniques which can be used in this type of situation, is to perform a "concept test" based on public opinion. This approach, however, is plagued with the phenomenon of non-commitment bias of interviewees, and tends to overestimate the ridership.

A new fixed route and fixed schedule transit service in Johnson City in Tennessee provided a rare opportunity to perform an investigation on the non-commitment bias through "before" and "after" surveys. The analysis of the non-commitment and actual responses of a Sample of residents revealed substantial bias. Overall, the non-commitment ridership estimate was about twice (100% greater than) the actual ridership. It was also observed that the bias was higher for persons owning automobiles, and for work and shopping trips.