Yes, and most of the accidents are due to young inexperienced males in over-powered cars doing crazy overtaking maneouvers, or simply over-cooking it on the twisty roads. A huge percentage of the accidents are single-vehicle-rolled-into-field, or versus a tree. Some of the worst roads for the 'young loons' ( eg Aberdeen - Peterhead ) now have a lot of speed cameras on them. Don't know how much effect they are having.
There is an element of frustration too, when you get a timid driver behind a farm vehicle on a slightly twisty road. Sometimes, they will simply not overtake. Ever. Even when they reach the one long straight, and it's clear to do so. This causes massive tailbacks at 20mph, and sometimes people attempt a multi-overtake maneouver when it's just not safe to do so.
The A90 is horrendous for the reasons you state. It's part of my daily commute. They simply built it on the cheap, without proper intersections. People have to attempt to make right-turns onto the dual carriageway across fast-moving traffic, whth all the associated risks. They are only now starting to address this, with several new flyover intersections between Perth and Aberdeen.