If you think car traffic is bad and getting worse, you had better brace yourself for an explosion of freight traffic in metro Atlanta by 2030.

The Atlanta Regional Freight Mobility Plan, approved by the Atlanta Regional Commission board last week, paints a frightening picture.

MARIA SAPORTA • E-mail Saporta Recent columns

Between 2005 and 2030, it is projected that the flow of freight in the 20-county region will increase from 950 million tons to 1.7 billion tons, a 78 percent increase. And current projections are that more than 1.5 billion of those tons will be hauled by trucks.

So if you think our roadways are congested today, imagine an additional 140,000 trucks on our highways every day.

The ARC, in partnership with the Georgia Department of Transportation, has been working on the freight mobility study since December 2005. When it's come to transportation planning, the movement of freight often has taken a back seat to moving people in cars.

Yet the study demonstrates how important freight mobility is to the vitality of metro Atlanta's economy. The report states that metro Atlanta has more than 520,000 employees working in wholesale trade and transportation services. It is considered one of the top five distribution and logistics centers in the nation.

Much of that is due to having three interstate highways (I-75, I-85 and I-20) converging in the city center. The same is true for railroad lines that connect the Atlantic seaports of Charleston, Savannah and Brunswick with metro Atlanta and cities north and west.

And then there's Atlanta's Hartsfield-Jackson International Airport.

Air cargo is the fastest growing segment in the freight industry — expected to increase by 148 percent between 2005 and 2030. But, in terms of volume, air still will only represent .2 percent of the freight coming and going out of Atlanta.

The study did not make any assumptions that freight traffic will shift from one mode to another. Instead, it assumed that whatever product is being shipped by truck will continue to be shipped by truck.

That led to the conclusion that the market share of freight shipped by rail (now 11.5 percent) will slip to less than 9 percent in 2030. That means that more than 90 percent of all freight is projected to be shipped via trucks in our region.

Trying to accommodate all those additional trucks on our highways and roads could be tough.

So the study made several recommendations on how to manage that scary outcome.

It identified a "Regional Freight Priority Highway Network" to better handle increased traffic.

It calls for improving the operations of existing roadways through signal timing, signs and technology.

It recommended investing in existing highways to remove the freight bottlenecks at key interchanges — I-75 north at I-285; I-20 west at I-285; and I-75 south at I-675 — as well as other intersections across the metro area.

Finally, it urged the elimination or reduction of at-grade rail crossings at bottleneck locations, especially along truck routes.

But the real potential in the freight study is its recommendation to invest in the rail network. It believes the region should invest in improving rail capacity by double-tracking the rail corridor from Atlanta to Chattanooga and doubling the corridor between Savannah and Memphis going through Atlanta.

The study said there's a strong desire among regional leaders to promote the shifting of freight from truck to rail. At the same time, there's also great interest in developing commuter rail service in the region.

Such an approach would call for a public-private partnership between governments and the railroad industry. Railroads would benefit because they would be able to haul more freight at increased speeds.

The region would benefit by having fewer trucks on the road — a huge safety concern as well as a major cause of congestion. Also, commuters would be offered travel options other than their cars. Air quality would be improved by using rail, a cleaner mode of transportation. And shifting to more fuel-efficient modes of travel is becoming more important as energy costs continue to soar.

The challenge will be to figure out ways to get the governments and railroads working together to ease such a shift in freight traffic.

After all, that probably would end up being much less expensive than building a network of truck-only toll lanes, a concept that has been floated in the region during the past several years.

Only last week, the Georgia Department of Transportation released a separate study that showed truck-only toll lanes would only speed up traffic by about 10 miles per hour during the next 30 years.

Given that the cost of building a truck-only network of lanes would cost $13 billion, the DOT study said the state should not pursue truck-only lanes because they would not be an efficient use of limited dollars.

There was another problem with this concept. There was disagreement whether such truck toll lanes would be mandatory or voluntary. The trucking industry preferred a voluntary approach, while the private funders wanted mandatory lanes to ensure there would be enough revenue to pay for the lanes. It has been tough to reconcile those two positions.

Coincidentally, the ARC/DOT freight study was released the same week, showing the gravity of continuing to ship cargo the way we do it today.

Here is an opportunity to be strategic. How can the region best function in 2030? How can our region lessen our dependence on oil to serve our daily mobility needs — both with freight and people? And how can we invest as a society to alleviate the trend of global warming and develop in the most sustainable way?

If we're smart, we'll answer with rail.