The Bundesstraße 432 begins at the Schnelsen-Nord interchange of the Bundesautobahn 7 in the northwestern part of Hamburg and travels via Norderstedt, Kayhude, Nahe, Itzstedt, and Leezen to Bad Segeberg.

From Bad Segeberg, it continues between Warder and Wensin over the Wardersee, via Ahrensbök to Scharbeutz on the Baltic Sea.

[2] Shortly before Scharbeutz, between the A 1 and the railroad tracks, there are six explosive bays on the road as relics of the Cold War.

The five pioneer lockers (explosive bunkers) are located near the Blocksberg (Pansdorf) and are now used as homes for bats.

In November 2013, a roundabout with a north-south tunnel underneath was completed to reduce the dust load of the area.