nberry:
It is a TURN signal NOT a lane changing signal. Good drivers are always aware on US highways that people change lanes when the situation allows them to do so. Putting your turn signal on to change lanes is an unnecessary action. In fact it can cause accidents because people believe that once they engage the signal it is safe to make the lane change.
While we are at it, why bother using them at all?... I'm glad I don't have to drive in the states
Your theory could be applied at intersections and any other turn, using them there could also cause accidents according to you since once they engage the signal the may believe its safe to turn just the same as in a lane change... Anybody who can make such an assumption or desition should not be driving period.
Using turn signals in lane changes "when there is traffic behind and/or in front of you" is a basic safety measure, just like using a helmet on a bike or not speaking on the cell or eating while you drive.
Its essential to help avoid lane change collisions were drivers for example in the overtaing lane that approach at higher speed have time to adapt the speed, if the driver on the right takes the precaution of signaling the lane change before iniating the maneuver and cutting him off, or drivers caught by surprise by other drivers who initiate a lane change right into their lane when next to each other in the blind spot, or two drivers in the same lane both going into another lane at the same time to overtake another, or two drivers in a three lane road jumpinjg into the same middle lane from the to outer lanes. There are instances were they are not necesary, like if you are too far from other vehicles for it to matter, or like when returning to the right like after an overtake once if you have cleared the car by a long margin, etc (I admit I don't bother in those cases myself) but it doesn't cost anything to use when you are in traffic and its driving safety 101.
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