How convenient it would be to be able to pay your toll booth using your smart phone. This could reduce the headache of the toll booth collector or you looking for exact change also avoid the unnecessary frustration of the other cars behind you because of your inability to find the right change in the toll plaza.
With lakhs of vehicles using the toll plaza a majority of which are with out the prepaid cards it would be a boon to both toll booth operators and to those who are not regular users of the toll booth and prefer to pay cash during every usage. I guess this is where NFC is going to be helpful. Just a wave of your phone could initiate this smooth transfer.
After all this is the mobile age everything that is possible should be done using a mobile