The model: Speed signs A: maximum, matrix sign, advisory and zone

A1 (round, red border) = maximum speed, binding. A2 is the same sign with a grey stripe through it: end of maximum. A3 is the matrix sign — an electronic signalling sign above the lane — and counts fully as a traffic sign (Book p.238, p.49-50). A4 is the blue rectangular advisory sign: not mandatory, no fine for exceeding it. A5 is end of advisory. If a fixed sign and a matrix sign both show a speed at once, the lowest applies.