Exceptional vehicles are used when it is necessary to transport goods and materials with dimensions or weights exceeding the standard in traffic regulations. Those vehicles with cargo usually have the extra-large size and heavy loads, which increase the potential of damage to the infrastructure and is prone to overturning accidents. It is desirable to evaluate both the weight and the stability of exceptional vehicles. Therefore, this study proposes a computer vision-based method. Firstly, digital cameras are used to capture images of all the outer tires, and the parameters including the deformation and inflation pressure of each outer tire are obtained using computer vision techniques. Those parameters are incorporated into the developed equation to calculate the contact force/load of each outer tire of each axle. Then, the finite element model of the modular trailer is established to determine the relationship between the inner tire loads and the outer tire loads, i.e., the transverse distribution coefficients of each axle, which are used for the calculation of inner tire loads. The gross weight of the vehicle is then obtained by summing up loads of all the outer and inner tires. Finally, a two-stage approach is developed for the stability evaluation based on the center of gravity and the rollover safety margin. Field tests are conducted to verify the proposed method and the results indicate that the identification errors of gross vehicle weight are less than 8 %. The proposed method offers a new alternative for the vehicle and stability evaluation of exceptional vehicles.