Three major segments of the transportation industry are airlines, such as WestJet; railroads, such as Canadian National Railway (CNR); and transportation arrangement services, such as TransForce Inc. Recent financial statement information for these three companies is shown as follows (in millions of dollars):

a. Determine the return on assets for all three companies. Round to one decimal place.
b. Assume that the return on asset ratio for each company represents each company's respective industry segment. Interpret the differences in the return on assets in terms of the operating characteristics of each of the respective segments.