Image: Traffic © Pixtal, SuperStock

The next time you are driving, count how many times your fellow drivers fail to use their turn signals. Chances are you will run out of fingers and toes before the engine is warm.

Nearly half of all drivers either don't signal to change lanes or fail to turn the indicator off if they do, according to a newly released report from the Society of Automotive Engineers. Researchers observed 12,000 cars and found a failure rate on lane changes of 48%. One driver in four failed to use a signal to make a turn, the report says.

Those findings back up a 2006 survey conducted by Response Insurance in which 57% of American drivers admitted not using turn signals when changing lanes. Among drivers ages 18 to 24, 71% said they don't use their signals.