Millimeter wave (mmWave), as the primary frequency band for sixth-generation wireless systems, is a key technology to support lower latency and higher data rates in vehicle-to-infrastructure (V2I) communications. The ray-tracing (RT) based simulation method can be combined with channel measurements to overcome the measurement limitation in mmWave band. Because of a lack of research on using RT simulation data to analyze inter-cell interference (ICI) in specific scenarios, we conduct comprehensive research based on the RT simulation platform at Beijing Jiaotong University to study the V2I link channel in the mmWave band. In this paper, RT simulations for the V2I communication in the mmWave band (22.1-23.1 GHz) are conducted for a typical urban scenario considering high traffic flows. Three frequency planning (FP) strategies are adopted to find the best FP strategy to mitigate ICI and enhance system performance. The signal-to-interference-plus-noise ratio and the corresponding theoretical capacity are calculated. The methodology and analysis in this work will be useful in supporting researchers to design mmWave V2I communication systems in similar scenarios.