Members here may be aware of 'How to set the wing mirrors of a four-wheeler'.
I had come across a related input on the Team Fiat India forum 3-4 years ago. Just thought to share here briefly what I understood from that.
It is most common the set the wing mirrors in a way that you see a little of your vehicle's side and tail, mostly to check if any overtaking vehicle is too close and also while reversing into a tight spot. This may be needed for city drive. However, this may lead to blind spots on either sides. Blind spots can prove dangerous on highway driving.
Actually, two wing mirrors and a rear-view mirror should cover the entire rear and side areas that the driver can't look at directly while driving. This is not achieved when wing mirrors are set in the above-mentioned, common way.
One should turn the wing mirrors fully outward, i.e. the right mirror to max. right position and left mirror to max. left position. With this, the driver sitting in driver's seat should check the view in the three mirrors while a friend walks around the vehicle a full circle. It should be possible to see the person existing from one mirror view and immediately appearing in the next one and then in the next. Ideally, if the mirrors are at max. out positions, overlapped view (person visible in two mirrors) may not be seen. If the view is missing between wing mirror and RV mirror, turn that mirror towards the vehicle a little to get a continuous view. With this setting, the driver will be able to avoid blind-spots on both sides.
One should also confirm that the person enters the field of direct view of the driver after exiting from the mirror view. This also depends on the drivers' ability to look sideways.
One may choose this way of setting for highways, while the usual one for city.
Experts may comment and indicate mistakes, if any.