In Ubuntu, routes are not added as defined in rc.local file....why?

In Ubuntu, routes are not added as defined in rc.local file....why?

I need to setup my ubuntu pc single nic card ip as 192.168.1.6 for internet and 10.172.170.95 and 135.10.86.100 for my lan and for another network through my 4port DSL modem.So i defined like this.