Some forward-thinking media professionals are beginning to look for ways to reach millions of public transit riders with digital signage messaging.

There's a chill in the evening air; the days are getting shorter, and some of the leaves on the trees are hinting at an impending explosion of color. Fall must be upon us, and that can mean only one thing: The baseball season will soon culminate in a succession of playoff games, two pennant series and ultimately the World Series.

This year leading up to the Fall Classic, commuters entering the Times Square/Grand Central Shuttle or boarding MTA New York City Transit-branded subway cars designed to capture the feel of a baseball stadium will be immersed in TBS coverage of all four of the Major League Baseball Division Series and the American League Championship Series, or ALCS games.

A TBS press release announcing the campaign, which is crafted by CBS Outdoor, says,  "Riders will also experience video screens within the subway car, featuring up-to-date information on match-ups."

While one of the objectives of the campaign is to build interest among riders in the playoffs and ALCS games and encourage them to tune in at home, another is to take advantage of digital signage technology to reach a captive audience with advertising messaging. In the words of MTA Chairman and CEO Jay H. Walder, the Metropolitan Transportation Authority of the State of New York is "creating new, dynamic advertising opportunities utilizing the latest technology."

"Inviting advertisers to 'wrap' entire trains and the use of digital displays will generate a buzz among customers and advertisers alike," Walder said in the press release.

The TBS campaign follows an effort launched more than two years ago in the Raleigh-Durham, NC, area by Capitol Broadcasting Company and its flagship media property WRAL-TV to transmit mobile DTV signals to specially equipped busses set up to receive the signals and display news, weather, sports and other local-interest content and advertising on flat panel screens on-the-go.

It appears mobile digital signage is beginning to pique the interest of media professionals and is picking up momentum. That's quite understandable. Not only are passengers generally "trapped" in close proximity to the digital sign until the train, subway or bus comes to a halt, but also the size of the audience involved is hard to ignore.

According to one account of New York City subway and bus traffic, 7.7 million people use the vehicles daily throughout the city's five boroughs. Nationwide, the number of trips taken on public transportation is mind-blowing. According to the American Public Transportation Association, more than 2.5 billion trips were taken on U.S. public transportation in the second quarter of 2010.

With such a massive audience and technological developments that are making it easier to refresh digital signage content on-the-go as needed, expect to see more demonstrations of mobile digital signage. While it's likely to be a long time before every city bus, subway car and commuter train is equipped with digital signage technology, TBS' promotion of postseason baseball and WRAL-TV's mobile DTV transmission to digital signs on city busses demonstrate that forward-thinking media professionals view digital signage on-the-go as an up-and-coming medium worthy of serious interest.

When it comes to digital signage, take an environmentally friendly approach to communications makes good business sense.

Going green with digital signage isn't simply a matter of reducing the environmental impact of your messaging.

Replacing traditional signs -whether motivated out of a concern for the environment or simply to communicate more effectively- makes good business sense. To the uninitiated, that statement may be a bit surprising. But for those with experience communicating with both digital and printed signs it should quickly become apparent why the reasons to do the green thing and select digital signage as a communications medium is also a sound business decision.

In a past blogs, I enumerated the benefits to the environment of choosing to communicate via digital signage rather than with traditional printed signs. In this column, I wish to explore some of the real business benefits organizations can realize by going green with digital signage.

Cost savings: Could it actually be cheaper to replace environmentally unfriendly printed signs with the greener alternative of digital signs? Absolutely! Depending upon the type and quantity of printed signs being replaced, it is possible for a digital signage system to pay for itself in less than two years. For example, a casino that relies on lots of backlit transparent signs can reach break even in even less time by replacing them with digital signs. In this instance, the sheer quantity of signs needed to tell patrons about frequently changing entertainment acts and special offers along with the expense of the backlit signage medium make selecting digital signs a financially wise decision.

When it comes to the environment, digital signs can be updated frequently with powerful text, images and even video, and they also eliminate the need to manufacture the transparent plastic film and specialized inks required to print backlit signs and solve the question of proper disposal before it's even raised. Obviously, the specific type and expense of printed signs in use will impact when the financial break-even point is reached by choosing the digital alternative as well as the exact environmental consequences.

Message per meter: Closely related to the cost benefit of digital signage vs. printed signs is something I'm dubbing "message per meter." Digital signage networks have an innate ability to playback multiple pages -one after another- in an endless sequence just as a TV channel plays back a ceaseless lineup of entertainment, commercials, news and other content.

That ability means a theoretically unending sequence of desired messages can be played back on a digital signage network. It's almost silly to conjure up how printed signs would do something similar -wallpaper the entire planet? Clearly, when it comes to the number of messages communicated per meter (or whatever unit of measurement you desire) of space, digital signage wins hands down thanks to the element of time.

From the perspective of being green, winning the "messages per meter" crown makes digital signage a far more environmentally friendly alternative. From a business perspective, the ability to playback the sequence means more goods and services can be promoted per unit of wall space, which should positively affect sales.

Improved workforce productivity: Whether it's printed or digital signage, there is a pretty well established workflow to creating a given message. The former requires transport of people and actual end product at several points in the process. From the moment paper stock arrives at a printer till the time someone in an organization -or an outside contractor- actually hangs the finished printed sign, the transport never ceases, and nor does the carbon footprint associated with that process.

On the other hand, the digital signage workflow is far more efficient. There literally is zero transport of physical media and people required between the point of origination of a digital signage page and where it's displayed. Cutting out all of "the middlemen" needed from concept to delivery in a print workflow makes digital signs an attractive alternative from a productivity point of view, and reducing the transport of people and materials makes digital signs the greener choice.

Add to the efficiency equation the ability of some digital signage software applications to extract specific information from existing databases and facilities management software packages to automatically create digital signage pages, and the positive impact digital signage can have on the productivity of an organization becomes even clearer.

With benefits like these, it's clear going green with digital signage not only helps our environment but also is a sound business strategy.