The core idea is to bypass the isContract() check so as to become the owner of the target RoadClosed contract.
The operation can be divided into 3 steps in the contract's constructor:
addToWhitelist(address(attacker))changeOwner(address(attacker))pwn(address(attacker))
The identification of whether an address is a contract or not should not just rely on the exitcodesize, which can be manipulated to bypass.