Can a 4-length road ever be Longest Road in Settlers of Catan?

Suppose I have an 8-length road and Longest Road, but later someone splits my road in half with a settlement, leaving me two 4-length roads.

Assuming no one else has a longer road than me, do I lose Longest Road, given that my road no longer has a length of at least 5?

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The title change from "Can a 4 length road ever be the longest?" to "When would the longest road card be set aside?" changed the intent of the question, so I rolled it back. – Rainbolt Sep 1 '15 at 21:04

You lose longest road; by definition, none of you have a road with a length of at least 5.

From the rules:

Set the “Longest Road” card aside if—after a longest road is broken—several players tie for the new longest road or no one has a 5+ segment road. The “Longest Road” card comes into play again when only 1 player has the longest road (of at least 5 road pieces).

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What would happen if a settlement reduces the length of my road to 5, and an other player has also a road length of 5 and no other player has more than 5? Can I keep the card or do I have to set the card aside? – Johannes Kuhn Sep 1 '15 at 23:36
That's covered in Lance's answer (but really you should be asking it as a separate question). – Philip Kendall Sep 2 '15 at 6:24
@JohannesKuhn - And I quote, from this very answer, "Set the “Longest Road” card aside if—after a longest road is broken—several players tie for the new longest road". I'm not sure how that could be any clearer. Unless you are confused by the word "several"? "Several" means more than one, hence you and another player both having a road of length 5 means that "several players tie for the new longest road". So the card will be set aside. – AndyT Sep 2 '15 at 14:57

As per the official FAQ:

The longest road card is retained by it's current owner until one of two things happen:

1. Another player builds a road that is then longer than the longest road of the current card-holder. In this case, the new longest road owner takes the longest road card.

2. The longest road is broken by the placement of a settlement along its length (remember to obey the 2-step rule). In this case, everyone must check to see who has the longest road. If any single player has the longest road (note that it could be the same as the old player with the longest road) than that player takes the card and the two points. If more than one player has the longest road, or if no player has a road of at least 5 segments, then no one gets the longest road card and it is set aside. As soon as any player builds a longest road of at least 5 segments, then he may claim the card as normal.

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