While I was adding my work zip code to the Yahoo Local Traffic Widget, I decided to try and add my home zip code as well. Thus, I put a comma and a space between both zip codes and it showed multiple collisions in both areas. Then I decided to add another zip to the equation, but this time it didn't work.
So I decided to try again, by adding commas, but not a space between each one. This time I did it for all the zip codes that I have to drive through on a daily basis. Example: 92111,92117,92103,91936. It worked! Now, I can check the traffic on all routes from the office to my home.
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http://hints.macworld.com/article.php?story=20050527192836462