. 2008 May 1;7:20. doi: 10.1186/1476-072X-7-20
Copyright © 2008 Hu et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 9.
Dasymetric map of annual average daily traffic density.