| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent an operator of a vehicle from overlooking a factor other than the vehicle in the vicinity of a signal device which changes its signal cycle corresponding to a plurality of factors in an onboard communication device. <P>SOLUTION: A signal control device regards a vehicle factor resulting from existence of a vehicle as one of a plurality of external factors, changes the light color or the light color duration time of a signal device when receiving any external factor, and transmits signal device information including information of current light color and light color duration time after the change as well as specific information for specifying the external factor to a road. An onboard device acquires the signal device information and the specific information from the signal control device 2 (S410), and specifies whether or not the external factor which changed the signal device information is a vehicle factor based on the specific information (S460, S470, S510). Then, the onboard device outputs the specified external factor (S530, S560). <P>COPYRIGHT: (C)2012,JPO&INPIT |
