MICHELE NORRIS, Host: Today, we have a sound clip that could mean the difference between life and death on the road.</s>MICHELE NORRIS, Host: My name is David Huiner and I drive a chemical tanker big-rig.</s>MICHELE NORRIS, Host: Professional drivers test their air brake systems at the start of every day.</s>MICHELE NORRIS, Host: I need to know that if my compressor failed I would know about it before it was too late. So I pump and release my brakes.</s>MICHELE NORRIS, Host: If I lose too much air pressure my parking brakes will automatically set and bring my truck to a stop whether I want it to or not.</s>MICHELE NORRIS, Host: I'm over 40 years old and I had been driving a stick-shift car for about 25 years before I became a truck driver, and I thought that driving a stick shift in a truck was going to be a cinch but it is a little more challenging than I thought.</s>MICHELE NORRIS, Host: David Huiner and the sound of big-rig air brakes. We invite you to alert us to sounds that shape your life at work or play or any other noise that is caught your interest, go to npr.org and type in the word: sound clips.</s>SIEGEL: This is NPR, National Public Radio.
Listener and big-rig truck driver David Huiner says he relies on the sound of his air brakes to let him know that his truck is operating safely. He gives us an example.