Originally Posted by twiggy_D
The blindspots are quite a bit bigger than you'd think looking at those diagrams, it can be very hard for them to see anything that isn't a car.
Can be very hard to see anything, full stop. The Road Haulage Association once did a demo of HGV blind spots where they hid something like 38 cars behind an articulated box lorry.
I was once parking a rigid HGV in an awkward space. I got out and walked round to check all was clear. In the time it took me to get back in the cab, a light (car based) van drove round me and parked immediately behind my truck.
The first I knew of it - despite considerable caution and use of the mirrors - was the panicked sounding of the horn. By that time, I'd already pushed the van up on to two wheels and over to quite an angle. I didn't feel the truck hit, nor could I see him in the (large, correctly adjusted) mirrors, even once I knew he was there.
Unless you can see the driver in the mirrors and are pretty sure he's seen you, assume he has no idea you're there.