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.
You got it right. Just calc the area for all the census tracts and devide with the population. You could use x-tools or the following procedure: Click Editor on the Editor toolbar and click Start Editing. You can make calculations without being in an editing session; however, in that case, there is no way to undo the results.