The aim of this study is to analyze the impact of Plug-in Electrical Vehicles (PEVs) in distribution systems. The research focuses in power quality (THD) and the additional power amount required in the systems due to PEVs, subjects to different penetration scenarios. The methodology proposed consists in modeling the regular electrical vehicles (EVs) behavior pattern based on the 2009's National Household Travel Survey. The general procedure which applies for any distribution system analysis is proposed and assessed in the IEEE 13 nodes test feeder system. The results validation was done with DSSim-PC software in co-simulation with MATLAB. The PEV's drivers behavior was acquired by a previous Monte Carlo simulation. Once this model is defined, the load profile of EVs charger is introduced in the simulation software. This data allows to assign the arrival time and a charging estimated time for each regular user in the distribution system. The proposed methodology could be potentially used as a planning tool for PEVs penetration in existing distribution systems, therefore EVs inclusion studies could be enhanced.