Vehicular Ad-hoc NETworks (VANETs) are an emerging area of communication that offers a wide variety of possible applications, ranging from safety to entertainment. Internet Protocol Television (IPTV) services as an entertainment application over VANETs are considered to play an important role in the future of intelligent transportation systems and vehicular infotainment systems. Quality of Experience (QoE) has a strong impact when choosing adequate IPTV services for end users. Among QoE measures, TV Channel Availability (CA) is utmost important. In this work, we investigate the channel availability in IPTV services for vehicular users in different access network technologies. We focus on different traffic intensities and various number of TV channels and predict the CA of TV channels and the Channel Blocking Probability (CBP) to be expected. The comprehensive simulation experiments are achieved by means of an own simulation tool which is based on a detailed IPTV user behavior model.