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 . 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 .
Although the official law requiring turn signals was adopted in 1960, it took more than a decade to establish the details, which many people are still debating. SAE produced multiple reports throughout the 60s detailing the specifications for car turn signals, such as amber lens’s for front turn signals while rear signals could be red or amber, lit lens area had a minimum requirement of 50 cm2 , and a range of 60-120 flashes per minute . The SAE took these matters seriously because they viewed the turn signals as an information-transmitting system that delivered valuable information from driver to a driver.
Amber or Red?
In other designs, the car’s turn signals and brake lights are separated. However, with the red on red next to each other, it still resulted in a slower response time than having amber turn signals and red brake lights. While ECE International regulations require brake light and the rear fog light be at least four inches apart, there is no separation requirement for brake lights and turn signals in the U.S. . Different color and separation of rear lights is beneficial if it means that drivers have a quicker response time.
Spatial Configuration: Medially vs laterally placed indicator
According to a study at the Centre for Cognitive Neuroscience at the University of Wales, the participants’ errors and response time was quicker when the signal position relative to the headlight was compatible with the correct answers . That is, if indicating a left turn, the left turn signal should be placed on the left side of the headlight as shown in the top image. Thus, laterally-placed indicators, meaning lights placed on the outer side, create a faster response time than medially placed indicators, which are placed on the inner side. The figure below shows the subtle yet important differences in the indicator placements (Fig. 2).
Frequency of the signal
is the SAE standard which shows the SAE standard. The dotted area shows other parameters that produced similar satisfactory rates as those of SAE standards.
The Ticking Sound
Thermal flasher- older model
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