The investigation in this paper focuses on the impact of soundproof walls on vehicle-to-vehicle (V2V) communication in urban viaduct scenarios. Two measurement campaigns are conducted at 5.9 GHz band in the on-ramp and off-ramp scenarios in Wuhan, China. Line-of-sight (LOS) and non-line-of-sight (NLOS) regions caused by soundproof walls and their switch are emphasized. Akaike information criteria (AIC) is utilized to select the distribution that can best fit the amplitude fading. The results show Weibull distribution offers better fit in NLOS case and Ricean distribution is validated the best fit in LOS region. We observe that comparing to root mean square (RMS) delay spreads in NLOS region caused by soundproof walls, many strong multipath components (MPCs) in LOS cases will contribute to large RMS delay spreads. It is noted that there is fluctuation of fading depth between NLOS and LOS region. Our analysis illustrates that the reduction caused by soundproof walls cannot be neglected in V2V radio communication.