Putting money in the bank in return for interest is a major sin, and it is not permissible to put money in the bank in order to get interest to use for charitable projects, let alone benefit from it oneself. 

If a Muslim has put his money in a riba-based bank, then Allaah guides him and he repents from riba, then he has to get rid of the interest by donating it to charitable causes, because Allaah says (interpretation of the meaning): 

“O you who believe! Be afraid of Allaah and give up what remains (due to you) from Ribaa (from now onward) if you are (really) believers.

279. And if you do not do it, then take a notice of war from Allaah and His Messenger but if you repent, you shall have your capital sums. Deal not unjustly (by asking more than your capital sums), and you shall not be dealt with unjustly (by receiving less than your capital sums)”

[al-Baqarah 2:278, 279]

It is not permissible for him to benefit from it, either by paying taxes with it or doing anything else that will bring him benefit. 

Based on this, if this road belongs only to him, because it leads to his house, it is not permissible to repair it using this money, because it brings benefit to him. But if it is a public road which will benefit him and others, then there is nothing wrong with using this money to repair it. 

And Allaah knows best. 

See also the answers to question no. 292, 2370, 20876, 23346, 22392, 49677 and 30798. 

And Allaah knows best.