This is the 881st most frequent Hungarian word.
közlekedési
"Relating to transportation or traffic."
In this sentence, 'közlekedési' is used as an adjective modifying 'eszközök' (means), focusing on their role in transportation.
A közlekedési eszközök közül a metró a leggyorsabb.
Among transportation means, the metro is the fastest.
Here, 'közlekedési' describes 'szabályokat' (regulations), relating them to the domain of transportation or traffic.
A közlekedési szabályokat mindenki be kell tartsa.
Everyone must follow the traffic regulations.
The word 'közlekedési' here is the attributive form of 'közlekedés' (transportation), describing 'hálózat' (network).