The Probe Vehicle Information system is as system that collects information from cars equipped with sensors. Usually, various information is collected and transferred to a server, at frequent intervals. The information includes when and where the information was collected, which could lead to privacy problems. One way to solve these problems, is to use cryptographic anonymous authentication protocols. However, although the computational and network resource on cars are limited, anonymous authentication protocols tend to consume both heavily. In this article, we propose a new protocol using the combination cryptographic anonymous authentication and symmetric-key cryptographic authentication. This protocol can protect the users' privacy, while is efficient enough to be used for probe vehicle information systems. We also have conducted an experiment on a simulator with 5,000 virtual cars, and showed that this protocol is efficient enough for real use.