That's not difficult. You can simply use color information and detect salient regions. You may need to modify the original algorithm so that specifically the Red, Yellow and Green color of lights can be detected. 

thank you for your reply. I am using saliency toolbox and ı can't find  anything about it's using. What can ı do for  esing color information.  

Try to write your own code while reading the paper and get help of already existing code. This is the best way to understand the working of code. 

So you say that I write my code which is generate a salieny map(itti's method). am I right?

Yes, write the code, and change values of color maps for your desired results 

thank you very much for your reply. can you provide me with the matlab code for detecting saliency map by Itti's method or any guide regarding this method

Itt's Saliency Toolbox can be downloaded from http://www.saliencytoolbox.net/ .

thank you  but  I took a look at the code but I don't understand very well because ı think it is complicated.Can you say me which code ı wrote step by step?

DO you know anything Kadir–Brady saliency detector?

Can you tell me if you want to use saliency for traffic detection in a single image or in video sequence?