79 GHz band has recently attracted considerable interests as vehicular UWB radar for safe driving and self-driving because it should detect even small objects disassembled. Radar cross-section (RCS) is a measure of how detectable an object is with a radar. Some RCS measurement results for vehicles have been reported for 24GHz and 77GHz. However, these reports make no mention of the frequency characteristics of RCS values. This paper presents RCS values of various vehicles at 10 GHz, 24 GHz and 79GHz. It is shown from the measurement results that the RCS statics is proportional to logarithm of radar frequency and the RCS standard values of a vehicle and a human body can be regarded as Log-Weibull and Log-normal distribution.