Texas CDL General Knowledge Practice Exam 2025 - Free CDL Practice Questions and Study Guide

A broken exhaust system is particularly dangerous because it can allow poisonous fumes, including carbon monoxide, to enter the cab or sleeper berth. This is a serious health hazard, as these fumes are colorless and odorless, making them very hard to detect until they have reached harmful levels. Exposure to carbon monoxide can lead to symptoms such as headaches, dizziness, confusion, and even loss of consciousness, which can endanger the driver and any passengers as well as impair driving ability.

While the other options mention concerns like noise and fuel efficiency, these issues do not present an immediate threat to health and safety in the same critical way that the potential for toxic fumes does. Thus, the primary danger of a broken exhaust system lies in the risk of dangerous fumes entering the vehicle.