Vehicular data misuse may lead to traffic accidents and even loss of life, so it is crucial to achieve secure vehicular data communications. This paper focuses on secure vehicular data communications in the Named Data Networking (NDN). In NDN, names, provider IDs and data are transmitted in plaintext, which exposes vehicular data to security threats and leads to considerable data communication costs and failure rates. This paper proposes a Secure vehicular Data Communication (SDC) approach in NDN to supress data communication costs and failure rates. SCD constructs a vehicular backbone to reduce the number of authenticated nodes involved in reverse paths. Only the ciphtertext of the name and data is included in the signed Interest and Data and transmitted along the backbone, so the secure data communications are achieved. SCD is evaluated, and the data results demonstrate that SCD achieves the above objectives.