Then usable tread depth is compared to remaining tread depth in order to calculate tread wear percentages. For example, a tire that started with 10/32 of original tread depth and has worn off 4/32 (down to 6/32 of remaining tread depth) is 50% worn.
1 If you know the census tract number: Use the IRS list of 2014 Qualified Census Tracts by county. 2  If you have a street address: Visit HUD's interactive QCT Map and enter the property address to view what Census Tract the property is located.
What is a Census Tract? The Census Tract is an area roughly equivalent to a neighborhood established by the Bureau of Census for analyzing populations. They generally encompass a population between 2,500 to 8,000 people. Bureau of Census describes them as relatively permanent, but they do change over time. Therefore in order to compile data on a certain neighborhood over several decades it will be necessary to figure out the correct tract number(s) for a given neighborhood every census year. A census tract is smaller than a City but larger than a Block Group or Census Block, see this hierarchical presentation.