Next-generation telematics solutions are being driven by the maturation of recently deployed intelligent transportation systems, assisted by the integration of and rapid collaboration with information communication technology markets and the automotive industry. Examples of this trend can be found in DSRC contexts in which Wi-Fi and WiMAX have become very relevant in vehicular environments. Comprehensive field trials were conducted and relevant measurements were collected in physical environments to investigate the possible environmental factors that occur in roadside-unit-to-vehicle communication scenarios. In these carefully controlled automobile experiments, the most representative parameters are measured and analyzed for DSRC in dynamic environments (e.g., packet loss, latency, and delay spread). Using a systematic testing procedure and through measurement analysis, the communication performance and the operating reliability of wireless communications can be effectively verified; insightful improvements and helpful suggestions and contributions may thus be achieved for telematics system designs. Furthermore, a practical, reasonable, and standardized testing procedure is proposed, and it can be utilized in equipment verification and product certification.