The International Roughness Index (IRI) is a well‐recognized standard in the field of pavement management. Many different types of devices can be used to measure the IRI, but these devices are mainly mounted on a full‐size automobile and are complicated to operate. In addition, these devices are expensive. The development of methods for IRI measurement is a prerequisite for pavement management systems and other parts of the road management industry. Based on the quarter‐car model and the vehicle vibration caused by road roughness, there is a strong correlation between the in‐car Z‐axis acceleration and the IRI. The variation of speed of the car during the measurement process has a large influence on IRI estimation. A measurement system equipped with Z‐axis accelerometers and a GPS device was developed. Using the self‐designing measurement system based on the methodology proposed in this study, we performed a small‐scale field test. We used a one‐wheel linear model and two‐wheel model to fit the variation of the Z‐axis acceleration. The test results demonstrated that the low‐cost measurement system has good accuracy and could enhance the efficiency of IRI measurement.

The objective of this paper was to investigate the difference of behavior among the user and nonuser of bike-sharing systems. A revealed preference survey was carried out before the traditional stated preference survey, which helps to distinguish groups of respondents and variables design in the stated preference survey. Based on a large-scale combined revealed preference and stated preference survey on bus stations, metro stations, bike-sharing stations, shopping centers, and busy street corners in Shanghai, the structural equation models were used to analyze the main factor influencing people's choices and the satisfaction evaluation of bike-sharing system. It is found that bike-sharing is both a competitor and a complement to the public transit system. The users have high satisfaction with the bicycle-sharing system and the environment and bike-sharing stations to home or to metro stations are most important in influencing peoples' choice.

This study examined the factors which have a significant effect on the general satisfaction level with public bus services. By means of a practical survey in Shanghai, passengers’ attitudes to some specific attributes of the quality of the service were collected for analysis, as well as their overall satisfaction rating. Two methods were employed to analyze the relationship between their overall satisfaction rating and specific attributes rating: weighted power mean, and a generalized linear model. The main contribution of this work is as follows: we showed that the level of passenger satisfaction depended mainly on a few factors, and analyzed how these aspects affected their perceptions.