Puvvala, R. K. (2014). CRONBACH'S COEFFICIENT AS A PERFORMANCE MEASURE TO ASSESS LINK-LEVEL RELIABILITY. Unc Charlotte Electronic Theses And Dissertations.
Travel time reliability is commonly used in reference to the level of consistency in transportation service for a trip, corridor, mode or route in terms of its travel time. Typically, reliability is viewed by motorists in relation to their past experience and helps them assess their expected future trip travel time. With increasing congestion levels in most of the urban areas, there is a need to at least be aware of when and where the congestion occurs, thereby, enabling a motorist to estimate the probable travel time as closely as possible. This research proposes and demonstrates the use of Cronbach coefficient, `á' (a two-dimensional measure) as a performance measure complementing the traditional indicators to assess link-level reliability. INRIX travel time data of Charlotte, Mecklenburg County, North Carolina, for the years 2009 and 2010, were used in the current research. Most reliable travel time values for each link is determined, while also classifying the link-level performance into different levels of reliabilities using the scores that are evaluated in this research. Results from this research indicate that categorizing trips using their weekday/weekend information helps in identifying the trends of the travel times corresponding to the trips. Week-of-the-year is found to be one of the main factors influencing travel time. Also, most of the links were found to be highly reliable i.e., the trends of the travel times are identified.
