If only all cities used the same street name and numbering system. The problem is that there may be many similar streets and allowing for incorrectly entered values may actually match another address. The problem becomes how much flexibility to you allow when keying addresses or doing searches? I have been to some cities where every road running north and south is a street and every road running east and west is an avenue. Then the number in each direction is different so you can always tell by an address where in the city it is located. I only saw that once but it made it very easy to get around town without using a map. Twice in Cumberland county my house was renumbered in order to standardize the system there. It only created more problems. The planners accounted for any size lot which was considered large enough to put a dwelling on so the numbers were standard by actual footage not by the property use or type. My neighbors house was 3 digits off from mine because technically we could break up the lot and put 3 houses in between us if we ever rezoned. Good plan, but when the mailing addresses changed all over town and your new address may have been someone's old address - well you can imagine the mess. Here in Greensboro I was surprised to find out that some streets have even numbers on the left and odd on the right on one side of town and just the opposite on the other side of town. I have NEVER seen that before and I've lived and traveled to a lot of cities in the U.S. I am convinced (so far) that Phoenix and Chicago are still the easiest cities to drive around. Some streets in San Franciso start at number 1 wherever the street originates so parallel streets can be numbered in opposite ways. Some places use compound numbers to show whether a street runs NS or EW so a street could be diagonal and be named N110 S in which case the road runs S from its start and 110 is on the N end of it. Those are the most confusing to me.

>>I just don't think it's humanly possible to achieve perfection in something like this because of the nature of the beast. I think, over time, you can develop a rules engine to cover most weirdnesses in addresses but I don't think you can get all, especially in Tracy's situation where she may have to parse "100 Main No W Ste 109" (note the missing street type and malformed suffix).
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>He beast is highly irregular, and I'm actually amazed that the humans somehow manage to live with it :).
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>Even in countries where there's more of a centralised regulation on these matters, there are various oddities. When we came here, the street numbers seemed quite odd, until we got the gist of it - and the street where I worked didn't help any, because it had only two numbers: 1 on the right, and 2000 on the left :).
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>We were used to simple sequential numbering, where #1 would be the first house on the left, #2 on the right and so on. But then if a lot was split and more houses inserted, house 26 would keep its number, and the added houses would be 26a, 26b etc - and sometimes 26c would come before 26. My street was another special case - the first block was supposed to be the warehousing area, so numbers on the odd side started on the second block, leaving first block unnumbered. So my number was 35, and the neighbor's across the street 76.
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>The specially weird thing were what you'd call projects. The apartment number would look something like 26 L1/U2/S12 (building #26, segment 1, entrance 2, apartment 12). Then they saw that was too complicated to remember and handle, so they started assigning street numbers per entrance, where all the previously assigned numbering schemes had to be renumbered... and a few hundred thousand people had to oPaperwork.refresh().
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>So, back to Tracy's problem - in her place, I'd write a lookup table with all the forms of an address, which would point to the exact address. The record for "100 Main No W Ste 109" would lead to "100 NW Main St Apt 109", so next time it appears, wouldn't need to be parsed again. Gradually, that'd lead to close to 99% of hits.