Road Signs and Markings
How signs are organised
Bulgarian signs follow the European Vienna Convention system. Learn the families: warning triangles (red border, white/yellow ground), priority signs (the yellow diamond 'priority road', the inverted triangle 'give way', the octagon 'STOP'), prohibition circles (red ring), mandatory blue circles, information squares and rectangles, and supplementary plates below a sign that modify it. The shape and colour alone often answer the question before you read the symbol.
Markings that decide liability
Longitudinal markings: a continuous white line may not be crossed; a broken line may be crossed when safe. A double continuous line is an absolute barrier. Transverse markings include stop lines and give-way lines. Special markings include pedestrian crossings (zebra), bus-stop zigzags, and yellow zigzags or boxes where stopping is prohibited. Motorcycle-specific markings are rare, but the general rules apply: you may not ride on a marked pedestrian crossing, and you may not straddle a continuous line to overtake.
Traps in sign questions
The classic trap is a sign with a supplementary plate that changes its meaning - for example a prohibition with a distance plate, or a 'no overtaking' sign that applies only to lorries via a plate. Another trap is confusing the 'give way' triangle with 'STOP': at a give-way you may proceed without stopping if clear; at STOP you must come to a complete halt. A third is the 'priority road' diamond, which tells you that you have priority at junctions along that road, not that you may ignore signals.
Worked example
You approach a junction and see a yellow diamond on your road and an inverted triangle facing the cross road. You have priority; the cross traffic must give way. But if a traffic light is red for you, the light wins - signs sit below signals in the hierarchy.
Rule of thumb
Identify the sign family first, then any supplementary plate, then check the hierarchy above it.