Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: About six months ago, I told you to prepare for "a trucking renaissance." Remember? Well, guess what -- it just pulled into the delivery bay. This morning, less-than-truckload weight trucker Old Dominion Freight (Nasdaq: ODFL) hit the gas and gunned its stock price up 10%. Its fuel of choice: an earnings beat.

So what: Citing a massive 21% spike in shipping volume, Old Dominion confirmed that the trucking industry is pulling out of a three-year slump, with the company nearly tripling quarterly profits and delivering $0.38 per share into the pockets of shareholders.

Now what: OD's winning quarter follows similarly strong results out of JB Hunt (Nasdaq: JBHT) this month and came simultaneously with much larger shipper UPS (NYSE: UPS) reporting a "beat" of its own -- two facts that suggest this revival may be as wide as it is deep. On the other hand, rival Arkansas Best (Nasdaq: ABFS) turned in more tepid results Monday.

The big question for trucking speculators remains: Which road will notorious yo-yo stock YRC Worldwide (Nasdaq: YRCW) follow?

Add it to your watchlist , and be first to learn the answer when YRC reports next month.

The Fool owns shares of United Parcel Service, but Fool contributor Rich Smith does not own (or short) shares of any company named above. The Motley Fool has a disclosure policy.

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