The present work investigates the variation of aerodynamic coefficients with the change in the angle of flow. A mathematical equation has been developed for predicting the aerodynamic coefficients, when a vehicle is subjected to crosswind. A tractor-trailer model has been utilised to demonstrate the effectiveness of the proposed equations. Flow analysis was carried out using Computational Fluid Dynamics (CFD) software. CFD simulations have been carried out on the tractor-trailer model at a wind speed of 25 m/s, for wind angles ranging from 0 to 180. The computational results obtained have been used for comparing the predicted aerodynamic coefficients. This mathematical model developed can be used for various aerodynamic investigations that involve large angles of attack