About this Article
Written by: Ju Young Lee
Written on: December 10th, 2014
Tags: civil engineering, electrical engineering, transportation
Thumbnail by:
About the Author
Ju Young Lee is a computer engineering student in the class of 2015 at the Viterbi School of Engineering. She hopes to use her computer engineering background to create applications in healthcare.
Stay Connected

Volume XVI Issue II > Car Turns Signals: Why They Blink, Make Sounds, and Look a Certain Way.
Although car turn signals seem like a trivial part of the car, they are a very important communication tool that drivers depend on. Each design decision of the turn signals from the frequency of the blinking, the sound of the ticking, the color of the lights, and their location on the car are carefully engineered to ensure the fastest response time for drivers to recognize other drivers’ intentions.


You are driving down a street and you need to make a left turn. You move to the left most lane and ignite the left turn signal. Then, you have to wait for what feels like forever for the traffic light to allow you to turn. During this long minute, have you ever looked for a different car whose car signals blink at the same rate as yours? Or, ever wondered why it makes that tick tock sound that we are all so familiar with now? Starting a signal is something that drivers do every day. As trivial as the turn signal can be, compared to other larger car component such as brakes, the engine, or air bag, it’s a very important communication tool for drivers to indicate their intentions.
According to the Society of Automotive Engineers (SAE), over 25% drivers neglect to use the turn signal when turning, and 48% ignore it when changing lanes [1]. As a direct result of this issue, they report over 2 million crashes. This is a huge portion of crashes compared to the estimated 950,000 crashes from distracted driving [1].