Improving the driving safety is one major concern for the design of intelligent vehicles. In this paper, we present a monocular vision based driver assistance system for dangerous traffic warning. The video sequences captured from a single camera mounted behind the windshield are used for lane detection and front vehicle identification. Two basic modules, lane departure warning system (LDWS) and front collision warning system (FCWS), are developed and then integrated on an embedded DSP platform for automotive electronics applications. Error analysis on system installation is carried out to verify the correctness of measurements. Experimental results have demonstrated that the proposed technique is able to achieve 97% of accuracy on dangerous traffic warning while maintaining the real-time processing requirement.