Why to they spell it T-H-R-U?

From:  "Pete"

Why on road signs they spell through thru
EX. No Thru Way what if a second grader was studying for a spelling test and saw the road sign

amr shalakani thought up this idea: 

mmm..i think a second grader failing his english test is much better than having a bunch of drivers dead cause it took them too much to read a sign and loosing their concentration off the road.

Catt agreed with amr shalakani: 

through is too long and too hard to spell, thru is much quicker to read

TB faithfully thought of these ideas: 

1). To save on painting. When you paint thousands of signs. Even deleting 1 letter can save a lot of money. 2). Allows for smaller signs saving money. 3). Drivers have only seconds to read signs.

I know all wrote this: 

they spell it "thru" because it is a shorter way to write it so it takes up less room. also it is commonly known what thru means. about the second grader with the spelling test well s/he would just ask someone what it is, and also I believe that it would be more of a third grade word then a second.

pavolka responded with this: 

For the same reason they assassinated the apostrophe. To make things shorter. That way on a given size of sign they can use larger letters that can be seen further away.

Mr. Obvious pointed this out: 

Road signs spell the word T-H-R-U to make the message short and to the point. It's like those "PED X-ING" signs: "PED X-ING" is much more efficient a message than "DANGER! PEDESTRIANS ARE CROSSING!"

the saint concluded with this: 

Well, think about where you've seen it spelled like that? Give up? How about road signs--as in "no thru traffic." It started as a way to condense the word "through" phonetically so it would fit better. Same goes for "hi" and "lo" on some product switch labels--shorter and more visible if you have limited space. This sort of thing is easy to do with English because there can be so many "silent" letters.