Colors as a key element of emotional (sentimental) impacts and interaction with its surrounding, which is the most important visual factor, has had a great importance in the history of art and culture of Iran for decades. This key element has shown its importance in several historical monuments and buildings. A large number of color theoreticians believe that colors affect the human beings’ spirit with a delicate awareness and importance of the subject . Today, due to undeniable importance of colors in our surroundings, the research on psychological impacts of colors has become a practical science. Besides buildings and nature, the color of fixed urban furniture and also vehicles, as an urban mobile element, make each city a collection of different colors. Colors are the most important outward characteristic of vehicles, which has the first and the most direct (immediate) effect on the sense of vision. Different color compositions made by various car arrangements in streets; induces a particular meaning. The research surveys the psychological impact of the color of vehicles in Tehran by statistical and field studies; and then compares the outcomes with the theories of color theoreticians on how each group of colors affects the human beings’ spirit. In the field study people thought of a combination of black, gray, white, blue and violet as absurdity and dullness; and a combination of white, light blue, yellow, orange, red and green induces happiness and joyfulness. In this paper, a field study is conducted by using a matrix like pattern put on the streets and at the same time, the vehicle production statistic acquired from an important car manufacturer sorted by the color of the vehicle. The color pattern in the street is known for different day time at the rush hours. In the field study, the combination of some colors to make a certain feeling has been gathered. Some specific colors shows different emotional impacts when they are in a combination of other colors. The public trend for each color of vehicle differs in each year by the number of the vehicles manufactured in production line of Iranian car manufacturer. These findings indicate that the color spectrums created by the cars arrangement in the streets of the city, are mostly white, silver, black and gray, which a neutral, cold and indifferent ones are. However, this neutral spectrum could create a sense of balance and equilibrium; totally, it implies a sense of absurdity and dullness. The number of joyful colors are so few that it is almost omitted. This paper introduces an stand alone investigation of the psychological impact of color spectrums created by the color of vehicles in urban pathways without the consideration of other colorful elements of the cities. It is expected to conduct further investigation on other combination of parameters like pathway colors, affects the urban pathways. Since the people trend to certain colors and the change of colors of public transportation vehicles are inevitable; this investigation must be conducted every year to achieve the psychological impact.