The recent advancements in electronics and computer networks, as well as the clear need for interoperability and connectivity makes communication technologies and algorithms crucial for the success of Intelligent Transportation Systems (ITS) applications. This survey paper provides a classification of communication technologies concerning their use in ITS and an assessment of their effectiveness. As a result, opportunities, gaps, and issues are identified in ITS and their associated Vehicular Ad-hoc Networks (VANETs). Even though several communication technology types are extensively used in ITS, there are challenges and issues regarding their operational effectiveness and reliability, which are thoroughly discussed in this paper. These challenges include the distance factor, bandwidth and medium access control, time/emergency situation, routing protocols, security, and privacy. In conclusion, this paper provides suggestions for improvement and directions for successfully utilizing communication technology in the area of ITS.