Strong productivity from an unseasonably warm winter should generally offset moderating year-over-year volume growth, the transportation analysts at Jefferies and Company say in their 1Q preview.

"We believe the number one theme for our transports in 1Q 2012 was the unseasonably mild winter weather," says the report from the investment banking firm. "The good news from this development is that all modes benefitted in some form from increased productivity and efficiency across most freight networks."

All should benefit on the cost side from faster transit times, decreased weather-related expenses and accidents and less fuel spent on idling. The bad news, Jeffries says, is that the warmer winter weather had negative consequences for coal demand, which was a highly publicized headwind in 1Q.

What remains unclear is whether the unusually warm winter, and improved productivity, might have pulled forward any earnings to 1Q, either in the form of economic activity or freight volumes.

"We believe this warm weather will have a positive impact on productivity and therefore operating ratios across our coverage," Jefferies says.

The ongoing driver shortage remains a constraining factor on capacity growth and spurred industry-wide driver pay increases of 1 to 2 cents per mile among many private fleets during 1Q, with signing bonuses in the $1,500 to $3,500 range. This could mean higher rates later this year among the public truckload carriers, if economic trends remain favorable.

There were differing views on the magnitude of the driver shortage, with some saying "tens of thousands" and others suggesting "hundreds of thousands."

Other key points of Jefferies' 1Q preview:

- Truckload volumes started the quarter slowly and ramped through March, marking a return to "normal" seasonality after outsized growth in 1Q during the past two years.

- Truckload rates appear to be tracking up 3% to 5% year over year. Surprisingly, the American Trucking Associations reported that LTL pricing was down year over year in January, the first negative datapoint seen in that space.

- Large TLs are taking share, with loads up 13% cumulatively since 2009. Small TL loads are down 2% during that period.

- It was clear from the large number of showcases at the Mid-America Trucking Show in Louisville, Ky., last month that natural gas is top of mind for OEMs, fleet owners, customers, and investors. Fleets are dominating the conversation less frequently, as the focus has turned increasingly toward possible cost savings. The industry still needs to address concerns surrounding infrastructure, payback periods, residual values, payload restrictions, and truck availability, although recent announcements from several OEMs (including Navistar, Cummins, Volvo, Kenworth, and Peterbilt) should help alleviate concerns, Jefferies notes.