Given that a strong transportation system is a key factor in economic development, transportation performance indexes are created for every state and the District of Columbia in addition to a national index. The state-by-state results are derived using the same methodology and the same indicators except where data is not available on a statewide basis. State indexes are calculated for 1995, 2000 and 2007; state-by-state results are shown here for 2007 only.
The 2007 state results range from 85.12 for North Dakota to 35.08 for the District of Columbia. While the District of Columbia is somewhat of an anomaly, New Jersey has the next lowest index with a value of 46.71.
Higher population growth rates and higher population densities are generally associated with lower index value based on an analysis of state results versus population data. While this warrants more rigorous analysis, a closer examination of the states with an index value of less than 60 reveals that these states experience significant pressure in terms of population growth, high levels of development, and limited access to or aging infrastructure. That said a highly ranked state like North Dakota should not disinvest in transportation infrastructure. At the same time, the pressures on the transportation system in states like New Jersey cannot be ignored.
In 2007, the average state result is 59.98 compared to the national result of 50.74. Note that the national index is not an average of the 50 states plus the District of Colombia, but rather based on a sample of the United States. If the United States was a state, it would rank near the bottom. When it comes to transportation system performance, the whole is not greater than the sum of its parts.