Roadside units play a vital role in vehicular ad hoc networks. Essential benefits of roadside units include providing information about traffic jams, accidents, and emergency messages to drivers in real-time. Because roadside units are expensive, developing a method to deploy them cost-effectively is pertinent. In this paper, we propose a roadside unit placement method using a limit number of roadside units to cover the intersections in an urban vehicular ad hoc network. Our strategy focuses on identifying potential candidate locations to place roadside units and minimizing the number of roadside units to deploy. Simulation results show that the proposed method outperforms existing methods in terms of the number of roadside units being used and the communication coverage.