At 23:00 you approach a ring road near a city with a fixed '80' sign. What applies here, compared with the motorway's ordinary day/night rule?
80 km/u, day and night — this ring-road exception does not change with the clock
130 km/u — it's night, so the standard applies, not the ring-road exception
100 km/u — the ring-road exception follows the same daytime window as the ordinary motorway
Explanation
False — trap: daytime-figure-as-standard, misapplied. The fixed ring-road sign of 80 km/u is not a day/night figure and is not reverted to 130 by the clock; it always applies, even at night (Book p.119).