How come U.S. version Prius doesn't have signal light on side mirror?

Assuming the driver changing lanes actually uses their turn signal.

SCH-I535

 

A significant fraction are here actually do use the signals.

Often as a substitute for shoulder checks and mirror checks.

 

Having grown up in the Boston area (driving a taxi there for a couple of summers) the alternative is to not use the signals, initiate the lane change and wait for someone to honk at you. Lather, rinse, repeat.

Using the turn signals eliminates the useful element of surprise

 

Aren't they more on the front of the mirror housing than the side? The arrows in the mirror itself seen more useful, both to the driver and those around.

 

Yes and no. The seems to be a single bright LED on the side and a reflective 'tube' that runs from this around the front. The led is brightest from the side and not so bright from the front. Can't recall if the led is also visible from behind, or if it is it is angled more for passing cars rather than blinding the driver.

 

Almost identical to the C, but a bit wider in the front towards the car.

 

I can see he mirror light blinking on my Prius when I'm I'm the driver's seat but it isn't blinding at night.

 

This is the same reason I prefer all vehicles have them. I'm a very courteous driver and I try and anticipate other people's desire to change lanes, especially into my lane.... Signals on mirrors helps with this.