Comparing Perceptions and Measures of Congestion

People's perception of congestion and the actual measured congestion do not always agree. Measured congestion relates to the delay resulting from field measurements of traffic volume, speed, and travel time. People's perception of congestion has historically been gathered through surveys. Perceptions of congestion can be influenced by relative year to year growth in congestion, improved or new transportation infrastructure, and societal attitudes on transportation. By examining both the perceived and measured congestion, the research should help relate "congestion" in context of the daily experience of commuters. The research project will be conducted in collaboration with IBM researchers who have been involved with commuter congestion surveys for the past several years. Both TTI and IBM bring considerable expertise in the area of congestion measurement. The reputations of these two agencies will generate considerable attention for the project. IBM has published a study the last three years on the attitudes of commuters from across the world on their daily travel (known as the "Commuter Pain Study"). The study is based on a survey intended to gather drivers' opinions about local traffic issues. The daily commute in some of the world's most economically important international cities is longer and more grueling than before imagined, reflecting the failure of transportation infrastructure to keep pace with economic activity. In the most recent report, the majority of motorists surveyed say that traffic has gotten worse in the past three years. The Texas Transportation Institute publishes an annual Urban Mobility Report (UMR) that measures urban mobility based on public and private traffic data for highways, streets, and transit. The Urban Mobility Report provides information on long-term congestion trends, the most recent congestion comparisons, and a description of many congestion improvement strategies for over 75 urban cities in the US. This research will utilize the IBM survey results to be able to connect the relationships between perceived congestion and measured congestion in some key US cities. TTI will focus on analyzing the traffic data used to develop the mobility performance measures, particularly for the international traffic data made available through this collaboration. TTI will also publish the research report comparing perception and measures of congestion. This will be targeted for end of calendar year 2011 or early 2012.