Illinois CDL Practice Exam

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Prepare for the Illinois CDL Exam. Utilize our comprehensive quiz featuring flashcards and multiple choice questions. Enhance your understanding and readiness for the exam with detailed explanations. Ace your CDL test and start your career in commercial driving!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

What describes the term "Brake Lag" in the context of air brakes?

The time taken for the driver to press the brake pedal down fully
The period required for the brakes to lock up
The delay between pressing the brake pedal and the brakes engaging
The time taken for the air to fill the brake lines

The correct answer is: The delay between pressing the brake pedal and the brakes engaging

In the context of air brakes, "Brake Lag" refers to the delay between the moment the driver presses the brake pedal and the actual engagement of the brakes. This delay is a crucial factor for drivers to consider when operating vehicles equipped with air brakes. Option A, which mentions the time taken for the driver to press the brake pedal down fully, is not the correct explanation for brake lag. Option B, referring to the period required for the brakes to lock up, is not an accurate description of brake lag in air brake systems. Option D, which states the time taken for the air to fill the brake lines, while related to the operation of air brakes, does not capture the concept of brake lag specifically.