MATS, LOUISVILLE -- Fuel economy continued to be a major theme of this year's Mid-America Trucking Show, as truck makers and suppliers predicted an improved year of heavy truck sales.

More than 79,000 attendees from all 50 states and 78 countries attended this year's show last week, with more than 1,000 exhibitors to choose from spread over 1.2 million square feet of exhibit space. HDT's editors were among the nearly 250 covering the show.

[For our complete coverage, click here. We are continuing to add stories, photos and more throughout this week.]

There weren't any introductions of entirely new trucks, engines or major components, but there was a generally optimistic air about the show.

Truck makers and suppliers overall were fairly optimistic in their predictions for truck sales this year, with Class 8 North American sales forecasts ranging from 220,000 to 265,000. If truck orders stayed at the same rate we've seen the first few months of the year we'd be on track for more than 300,000, but no one felt that was likely. Orders are being driven largely by small- to medium-size fleets and vocational markets, as most of the larger fleets have already been updating their fleets following the recession.

Daimler Trucks North America was one of the most upbeat, forecasting Class 8 sales in North America to reach 261,500, up from 236,500 last year. DTNA projects the total NAFTA Class 6-8 market will be up 10% or more compared to 2013. The company already has added capacity of approximately 100 trucks per day, an increase of about 20%, in the most recent quarter compared to the fourth quarter of 2013.

With most of the low-hanging fuel-economy fruit already picked from the vine, truck makers and suppliers are emphasizing weight savings and incremental fuel-savings improvements through advanced aerodynamics and engine control systems designed to help drivers manage fuel economy. Light weight was a factor in everything from trailers to axles and suspensions to wheels and alternators.

One of the exhibits generating a lot of buzz was the Walmart Advanced Vehicle Experience (WAVE) “demonstration concept” tractor-trailer, is said to be 20% more aerodynamic than the company's current trucks.

The 6x2 configuration was prominently displayed by several truck makers and drivetrain component manufacturers. Automatic lift axles are a new option for diminishing-weight loads.

Most OEs had natural gas equipment on display, but unlike last year, it did not figure prominently in most press announcements.

Almost all truck and engine makers were emphasizing uptime and customer support. The manufacturers are ratcheting up their ability to diagnose and resolve customer complaints before they results in serious delays, and telematics and remote diagnostics are a key part of that.

Tire producers were promoting their second-tier brands, perhaps in recognition that the premium product may be beyond the reach of many smaller fleets and owner-operators, and as a way to retain brand-name market share as recognizable imported brands begin to gain prominence.

There also was an increased emphasis on trucking image. In addition to the traditional Goodyear Highway Hero awards ceremony, TravelCenters of America also paid homage to exemplary drivers with its first Citizen Driver Awards, while a coalition of groups announced a new image campaign, Trucking Moves America Forward.

Next year's Mid-America Trucking Show will be March 26-28, 2015.