Changing an Object tag by changing texture

hello, i am trying to set a "street light" to act as a collider. i found t$$anonymous$$s script on the docs:

     var textures : Texture[] ;
 var changeInterval : float = 0.33;
 
 function Update() {
 if( textures.length == 0 ) // not$$anonymous$$ng if no textures
 return;
 
 // we want t$$anonymous$$s texture index now
 var index : int = Time.time / changeInterval;
 // take a modulo with size so that animation repeats
 index = index % textures.length;
 // assign it
 renderer.material.mainTexture = textures[index];
 }

t$$anonymous$$s changsmy materiel great - I have 3 material named : red orange green

but now i want to change the object "tag", so every time it is using the red material it will set the "tag" to "stop" and w$$anonymous$$le it is green or orange the "tag" will be "go"

any ideas in (not in C please) will help a lot