- Airports: Total number of airports. Runways must be useable, but may be unpaved. May not have facilities for refuelling, maintenance, or air traffic control.
- Airports > Per capita: Total number of airports. Runways must be useable, but may be unpaved. May not have facilities for refuelling, maintenance, or air traffic control. Per capita figures expressed per 1 million population.
- Commute > Distance: Distance. Based on 0-50 contributions for Argentina, Armenia, Austria and 63 more countries and 50-100 contributions for Australia, Brazil, Germany and 5 more countries and over 100 contributions for Canada, India, and United States. The surveys were conducted by numbeo.com from January, 2011 to February, 2014. See this sample survey for the United States, respondents were asked "Distance".
- Gross value added by transport, storage and communication: Gross Value Added by Kind of Economic Activity at current prices - US dollars.
- Highways > Total > Per capita: total length of the highway system Per capita figures expressed per 1,000 population.
- Motor vehicles: Motor vehicles per 1,000 people
- Ports and terminals: This entry lists major ports and terminals primarily on the basis of the amount of cargo tonnage shipped through the facilities on an annual basis. In some instances, the number of containers handled or ship visits were also considered.
- Rail > Railway length: Railway length in kilometers.
Road > Motor vehicles per 1000 people:
Motor vehicles per 1000 people.
No date was available from the Wikipedia article, so we used the date of retrieval.
- Road > Motorway density: Meters of motorway per square kilometer.
- Road > Motorway length: Total network length of all motorways in km.
- Road network length > Km: Length of road network in kilometers in European Union countries.
- Roads > Passenger cars > Per 1,000 people: Passenger cars (per 1,000 people). Passenger cars refer to road motor vehicles, other than two-wheelers, intended for the carriage of passengers and designed to seat no more than nine people (including the driver).
- Roadways > Unpaved: This entry gives the total length of the road network and includes the length of the paved and unpaved portions.
- Waterways: The total length and individual names of navigable rivers, canals, and other inland bodies of water.
SOURCES: CIA World Factbooks 18 December 2003 to 28 March 2011; traffic; United Nations Statistics Division; All CIA World Factbooks 18 December 2003 to 18 December 2008; United Nations World Statistics Pocketbook and Statistical Yearbook; Wikipedia: List of countries by rail transport network size (Long List); Wikipedia: List of countries by vehicles per capita; https://www.cia.gov/library/publications/the-world-factbook/fields/2085.html, Roadways.; International Road Federation, World Road Statistics and data files.