关键词: 城市交通, 抽样率, 误差, 居民出行调查, 可靠性

Abstract:

Resident trip survey is one of the most important survey categories of urban transportation planning, which is mainly conducted via questionnaires, household and sampling surveys at present, whose sampling rate can directly affect the precision or the size of error when arriving at the conclusions of the surveys. This paper firstly introduced the concepts and methods relating to error analysis, such as absolute error, significant digits and error propagation etc., and established the reliability evaluation criteria. Based on the information and main conclusions of the resident trip survey in downtown area of Nanjing in 2011 and 2012, it analyzes the reliability of the data of average numbers and mode structures of resident trip. The results shows that: the key conclusions are not reliable under the current adopted sampling size and sampling rate to investigate resident trip characteristics, and it is difficult to reflect their respective approximate value, as well as to compare the magnitude of the data between different years; the survey sampling rate to meet the precision requirement should be as high as 9%. Finally it is pointed out that the recommended values of sampling rate in some guidelines are lack of scientific support.

Key words: urban traffic, sampling rate, error, resident trip survey, reliability