The monitoring effect is influenced by haze which can make targets in images blurred. To resolve this problem, an improved image dehazing method based on dark channel prior by using the guided filter and adaptive color levels adjustment is proposed. Firstly, mapping operations are executed to estimate the atmospheric composition and transmissivity according to dark channel prior. The estimated value of transmissivity is optimized by using the multi-dimensional guided filter. Then, an initial dehazed result is generated according to the inverse process of image degradation. The light intensity of the initial result is usually low, which makes monitoring equipment hard to perform further actions. Thus multi-channel adaptive color levels adjustment is finally used to optimize the initial result. Experimental results show that the haze removal images have higher light intensity, contrast and better sharpness. The edge and detail features are enhanced significantly. The dehazing effect is remarkable, and the adaptability of the proposed method is high aiming at traffic images collected in hazy weather.