What are the chars that the url can include?

[eluser]Aken[/eluser]
Because you're using (:any). That means any characters, including /. If you don't want to include another slash, you have to specify only the characters that you're going to use in the segment for your titles. Something like this will use only letters, numbers and the dash (-) char.

Code:

$route['news/([a-zA-Z0-9\-]+)'] = 'news_ci/article/show/$1';