This is the 1514th most frequent Russian word.
пешехода
"Пешехода" is the genitive singular or accusative plural form of "пешеход," meaning "pedestrian."
In this example, 'пешеходах' is used in the prepositional case, plural form, as part of the phrase 'о пешеходах', meaning 'about pedestrians'.
Мы говорили о пешеходах и их безопасности.
We talked about pedestrians and their safety.
The word 'пешехода' is used in the accusative case as the direct object of the verb 'увидел', meaning 'saw'.
Я увидел пешехода, который переходил дорогу.
I saw a pedestrian who was crossing the road.
Here, 'пешехода' is also in the accusative case as the object of the verb 'защищать', meaning 'to protect'.