@BOOK{NAP10938, author = "National Research Council", title = "Letter Report to the Bureau of Transportation Statistics", doi = "10.17226/10938", url = "https://nap.nationalacademies.org/catalog/10938/letter-report-to-the-bureau-of-transportation-statistics", year = 2004, publisher = "The National Academies Press", address = "Washington, DC" }