Here are a few ideas....
1. Making them understand that our country,all over the world,is known as a country where people give immense respect to the senior citizens and so encouraging them to live up to that.
2.Making them understand that they too will go through that phase of life and that they should behave in the same way,they want other to behave with them.

Hope that's helpful. :)
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I appreciate this question  very much. You have brought out this into open and hope that this will trigger a campaign soon. 

Some time back, I have seen a campaign in Mumbai about giving way to Ambulances - the catch line was " Imagine some one near and dear to you in that ambulance". It was indeed thought provoking and makes everyone to give way to Ambulance. The campaign was so effective, these words were ringing in my ears whenever I hear the blare of an Ambulance Siren.

I think such a campaign at our localities to make them think their parents / elders instead of someone whom they see at public places. This might make people more sensitive towards senior citizens.

I understand that in Japan, the children are taught to respect the elders
from very young age - may in view of the fact that Japan has maximum percentage of old persons.