The recent groundbreaking for the FrontRunner South line is a fresh reminder of the stakes involved in this region's transit future. On Sunday the Daily Herald took a fresh look at the costs and questions. This is no small bet. Building more rail connections in our area will cost nearly $1 billion before it is done. Is it worth it?

Government and civic leaders have hailed FrontRunner South. It would run about 44 miles from Salt Lake City to Provo, with Draper, Lehi, American Fork, Vineyard and Orem among stops.

Certainly Utah Valley needs more transportation options. Interstate 15 is already choked with traffic at rush hours, and the looming reconstruction of the highway threatens to make things much worse. Meanwhile, both Salt Lake and Utah valleys are trying to reduce air pollution. Frontrunner is meant to take cars off the road, helping to clear up both I-15 and the atmosphere.

The surge in the price of gas to $4, even if it has abated somewhat, acted as a powerful reminder that the nation should not put all its eggs in one basket, but should diversify its transportation network. The FrontRunner North line from Salt Lake to Ogden has already opened, and the Utah Transit Authority holds it up as a good omen for the future. In June, ridership was above expectations at about 7,800 trips per day. Riders have generally given it rave reviews.

Commuter rail has drawn critics, however. A key statistic in the debate is the cost per vehicle removed from the freeway.

FrontRunner North's 7,800 trips per day compare to about 140,000 daily car trips along the same stretch of I-15. That's only a bit more than the number of daily trips between Provo and Salt Lake City. If all of the train riders previously drove, FrontRunner removed 5 percent of the traffic from the road at a cost of $611 million, plus ongoing costs paid for through taxes and boarding fees. That's a lot of money for what might seem like a small change in the traffic patterns.

Transit officials defend the travel benefits. With I-15 at the max, any relief for traffic is significant, they say. When the I-15 rebuild begins in earnest -- before FrontRunner South opens -- it's easy to predict that plenty of drivers will wish the commuter rail line had been built sooner so they might have a chance to take it.

Other planning experts say commuter rail offers improvements in quality of life that may be hard to quantify in dollars and cents but are nonetheless real. Rather than face the daily highway grind, commuters can read a newspaper or do some work, relaxing while drivers on I-15 are creeping along.

It's not just a luxury, according to some experts. It's said that companies considering whether to move to an area want to have transportation options. Any business thinking of relocating here will see that, for all practical purposes, the current transportation options from Utah Valley to the state's main city are, basically, Interstate 15 and helicopter.

In the short run, the pros and cons of train and auto commuting will be getting a good comparison. Legacy Highway opens Sept. 13, and the 14-mile stretch through Davis County is projected to carry up to 30,000 vehicles a day, compared to the 7,800 daily trips on FrontRunner North.

The highway and the rail line cost roughly the same. Some observers feel that will be almost like a well-run experiment on the comparative benefits of highway and rail transit.

That might be a hasty conclusion. FrontRunner South is part of a larger UTA project, FrontLines 2015. The agency plans to build four more light-rail lines in conjunction with the commuter rail lines. Evaluating the success of any one part has to wait until we evaluate how the whole network would run.

Rail transit should be judged in the even longer timeframe. Advocates point out that rail corridor costs are heavily front-loaded. Once the tracks are in, the biggest cost has been paid for a half-century or more. Highways, however, must constantly be repaved and reworked.

Look at cities such as New York and Chicago, where commuter rail (and subway) tracks were put in many decades ago. The expense may have seemed large then, but those transit lines have paid for themselves many times over in the years since.

Utah County voters seemed to agree when, two years ago, they voted overwhelmingly to approve a quarter-penny sales tax increase to fund commuter and light-rail construction. If people are given the question directly, and are willing to put their money down, then by all means the ventures are worth taking.

Nevertheless, transit officials and area residents need to keep a close eye on the progress and performance of FrontRunner and other planned transportation efforts. The coming years will undoubtedly spring new developments on us, and it's urgent that planners remain focused on costs and benefits, and show flexibility in adjusting to changing circumstances.

Do you agree?