Computing travel time when the exact address is unknown: a comparison of point and polygon ZIP code approximation methods

Table 2 Pairwise correlations comparing actual travel times to four estimation methods, for urban and rural areas of Arizona (AZ) and New Hampshire (NH).

	Estimation Method
Location of actual travel time	Geometric Centroid	Population Centroid	Service area based on LandScan	Service area based on area
AZ Urban	0.957*	0.994*	0.991*	0.957*
AZ Rural	0.988*	0.995*	0.997**	0.980*
NH Urban	0.920**	0.966	0.967	0.933*
NH Rural	0.988*	0.991*	0.992*	0.986*

ISSN: 1476-072X