Learn Finnish: Huonosta kelistä johtuen rekat joutuivat odottamaan. - Due to the bad driving weather, the trucks had to wait.

The word johtuen (due to) acts as a postposition that strictly requires the preceding words to be in the elative case (-sta or -stä). Because of this rule, both the adjective huono and the noun keli must take this ending.

Where does the word johtuen come from?

It is formed from the verb johtua (to result from, to stem from). Grammatically, it is an advanced infinitive form (the second infinitive instructive), but it is very common and best memorized simply as a fixed postposition meaning 'due to' or 'owing to'.

Why does the sentence use kelistä instead of the more common word for weather, säästä?

While sää means general meteorological weather, keli specifically refers to the physical conditions for traveling, such as driving, walking, or skiing. Since this sentence is about trucks being delayed on the road, keli is the most precise word to describe the bad driving conditions.

Why is the verb 'to wait' in the form odottamaan rather than the basic dictionary form odottaa?

The verb joutua (to have to, to end up doing) has a strict rection: it always requires the following verb to be in the third infinitive illative form, which ends in -maan or -mään. The trucks effectively 'ended up into waiting'.