die Umleitung
detour
An alternative route for traffic that is set up when the normal route is closed or blocked.
Wegen einer Baustelle mussten wir eine lange Umleitung fahren.
Because of roadworks, we had to take a long detour.

detour / redirection
Loading your saved state.
detour
An alternative route for traffic that is set up when the normal route is closed or blocked.
Wegen einer Baustelle mussten wir eine lange Umleitung fahren.
Because of roadworks, we had to take a long detour.

'Umleitung' is a compound noun made from the prefix 'um-' (around) and 'Leitung' (from the verb 'leiten', meaning to lead or guide). It literally describes 'leading around' an obstacle.
Die Umleitung führte uns durch kleine Dörfer.
The detour took us through small villages.
The noun 'die Umleitung' (the detour/redirection) describes the process or result of the separable verb 'umleiten' (to redirect/divert). When traffic is redirected, a detour is created.
Man muss den Verkehr umleiten, um die Brücke zu reparieren.
They have to redirect the traffic in order to repair the bridge.
In traffic contexts, typical phrases are 'einer Umleitung folgen' (to follow a detour), 'eine Umleitung fahren' (to take a detour), or 'eine Umleitung ist ausgeschildert' (a detour is signposted).
Folgen Sie der ausgeschilderten Umleitung.
Follow the signposted detour.
In technical contexts, people often talk about 'eine Umleitung einrichten' (setting up a redirection) or 'eine Umleitung löschen' (deleting a redirection). Common examples are 'Anrufumleitung' (call forwarding) or 'E-Mail-Umleitung' (email redirection).
Ich habe eine Umleitung für mein Telefon eingerichtet, da ich nicht im Büro bin.
I set up call forwarding for my phone because I am not in the office.
detour
'Umweg' and 'Umleitung' both have to do with taking a route other than the direct one. An 'Umweg' is the longer or more complicated route that you take. An 'Umleitung' is usually an officially set-up alternative route, for example because of a road closure. You can say: the 'Umleitung' often leads to an 'Umweg'. In figurative use, 'Umweg' can mean a roundabout method, while 'Umleitung' more often means the forwarding or redirection of something, such as calls or data. The words are easy to confuse because they often occur together in traffic contexts.

Nach dem Unfall wurde eine Umleitung über die Nebenstraße eingerichtet.
After the accident, a detour was set up via the side road.
Der Weg über die Dörfer ist ein Umweg, aber heute ist er schneller.
The route through the villages is a detour, but today it is faster.