Honestly, I don't think this reduction would have much effect in the price of gods and services in this wrecked country. The tax they impose on these goods at boundaries and toll gates are the main causes of inflation of prices. When people complain about the transportation costs, petrol is the least of their worries. You'll have to keep settling touts and force men handsomely before you're allowed to peacefully supply your good to the intended destination.
Take for example, the exchange rate want down in Naira's favor up to nearly #1k to $1, but the prices of things didn't really follow suit because the taxes imposed on these goods were amplified, so the effect was not really felt.