A terminal device includes: a candidate acquiring unit configured to acquire reverse traveling candidate information including positional information and traveling direction information of a vehicle when a candidate determining unit configured to determine whether there is a likelihood that the vehicle is traveling in reverse determines that there is a likelihood that the vehicle is traveling in reverse; and a candidate transmitting unit configured to transmit the reverse traveling candidate information to a rearward server configured to determine whether the vehicle is traveling in reverse based on the reverse traveling candidate information.