What rights do I have on street road in front of my house ?

I purchased a piece of land and there was two roads were proposed later on land dealer proposed to sell one road having width of 18 feet to me and my neighbor ( who has a house just opposite of the road. I got 12 feet and neighbor got 6 feet. Now due to some reason I am asking two more feet and asking for land registration, the land dealer agreed for the same. Is there any issue if in future my neighbor complain to any civic body or court?