NCTUns is a novel network simulator and emulator that has many unique features over traditional network simulators and emulators. It is an open-source software running on Linux and is being used by many researchers in the world. According to the NCTUns official web site (http://NSL.csie.nctu.edu.tw/nctuns. html), as of June 1, 2008, more than 11,546 people from 124 countries have registered and downloaded this software and these numbers are still fast increasing. In its 5.0 release, NCTUns provides a complete implementation of the IEEE 802.11(p)/1609 standards defined for wireless vehicular networks. In this paper, we present the capabilities of NCTUns 5.0 focusing on its uses for IEEE 802.11(p)/1609 wireless vehicular network researches.