Illinois CDL Practice Exam.

The requirement for two yellow or amber lights on the upper front corners, along with red lights on the rear, is critical for enhancing visibility and safety for larger vehicles such as second division or combination vehicles. These additional lights serve multiple purposes: they help in making the vehicle more conspicuous on the road, especially in low visibility conditions, and indicate the vehicle's dimensions to other road users. The yellow or amber lights at the front signal to other drivers that a larger vehicle is present, helping to prevent accidents. The red lights at the back are standard for most vehicles, signaling their position and stopping intentions. This combination of lighting ensures that larger vehicles are adequately visible from all directions, mitigating the risk of collisions and improving overall roadway safety.