Anecdata alert:
Many years ago, my dad told us of a scare he'd had at a newly-installed mini-roundabout. (Cambridge, junction of Lensfield Road (LR) and Trumpington Street/Road (TS/TR) "Newly-installed?" I hear you ask. "Many years ago" I re-iterate.)
He was heading south on a bike from TS to TR. Northbound, there are two lanes. The left lane is for staight-on TR to TS, the right is for a right turn into LR. The right lane was empty, so he set off, thinking that nothing would be turning right. What he had missed was the hooooge artic in the left lane, turning right. It couldn't get round the corner from the right lane, so had to be in the straight-on lane to turn right.
The warning - All road users should expect the unexpected. The lorry driver did, as he stopped dead and braked when my dad went across the roundabout in front of him.