This article presents a survey on vehicular telematics over heterogeneous wireless networks. An advanced heterogeneous vehicular network (AHVN) architecture is outlined which uses multiple access technologies and multiple radios in a collaborative manner. The challenges in designing the essential functional components of AHVN and the corresponding protocols (for radio link control, routing, congestion control, security and privacy, and application development) are discussed and the related work in the literature are reviewed. The open research challenges and several avenues for future research on vehicular telematics over heterogeneous wireless access networks are outlined.