RALEIGH – It’s all well and good to dream big and wax philosophical – I’ve been known to partake from time to time – but those who want to contribute meaningfully to the political debate should at least attempt to keep their musings within the realm of the possible.

It’s a rule that mass-transit boosters rarely follow.

In North Carolina and across the country, politicians and activists are pointing to recent increases in bus, van, and train traffic as evidence for two propositions. First, they argue that higher transit ridership reflects a permanent change in consumer behavior (based on $100+ a barrel oil in perpetuity) that makes some planned highway and tollway projects superfluous. Second, they argue that higher transit ridership offers cities an opportunity to alleviate congestion, air pollution, and other environmental concerns associated with vehicular traffic.

Neither argument holds up where the, uh, rubber hits the road.

The fundamental problem is simply one of magnitude. You can post 10 percent, 20 percent, even 30 percent growth rates for years and not really make much of a noticeable dent if you’re starting from a low base. So how low is the base when it comes to mass transit’s share of North Carolina commuting trips? As part of a massive study David Hartgen and some UNC-Charlotte colleagues did for JLF last year, his research team reported these percentages:

• Durham-3 percent
• Charlotte-2.6 percent
• Winston-Salem-1.5 percent
• Greensboro-1.3 percent
• Raleigh-1.2 percent
• Wilmington-0.9 percent
• Asheville-0.8 percent
• Fayetteville-0.8 percent

As is immediately evident, if the goal is to shift commuting patterns enough to obviate the need for major highway expansions or tollway projects in and around North Carolina’s congested major metros, transit would have to post permanent triple-digit increases in ridership. We’re nowhere close to this point. Before the oil-price spikes, the vast majority of North Carolinians traveled by personal automobile. After the oil-price spikes, the vast majority still travel by personal automobile, though in some cases not quite as far.

Realism is called for, here. A couple of years of 10 percent jumps in bus riders only represent a few thousand people statewide. That doesn’t come close to eliminating the need for new road projects that will each carry many tens of thousands of commuting trips a day.

The same lack of realism lies behind the assertion that transit expansion will have significant environmental benefits. Trains and buses still run largely on fossil fuels, be they diesel or electricity generated mostly by coal plants. In theory, transit could reduce energy consumption per person, but in practice transit often consumes more energy and emits more carbon dioxide per person because so many buses and train cars operate much of the day with few riders. As Randal O’Toole explained in a recent analysis for the Cato Institute, that’s not the end of the “carbon footprint” comparison:

Even where rail transit operations save a little energy, the construction of rail transit lines consumes huge amounts of energy and emits large volumes of greenhouse gases. In most cases, many decades of energy savings would be needed to repay the energy cost of construction.

None of which is to say that increased transit ridership in North Carolina – which is essentially a bus phenomenon, except in Charlotte – isn’t worth noting and accommodating. At JLF, we’ve long favored judicious use of bus and van pools to serve disabled and disadvantaged people, for whom transit service is basically a public assistance function, as well as any “choice” riders who want to switch from driving, as long as they pay a reasonable fare. Furthermore, while increased bus service as a whole would have scarcely noticeable effects on North Carolina commuting patterns, a particular bus route might at certain times of the day be a good investment along a particular, highly traveled corridor.

Again, it’s a matter of magnitude. Too many urban policymakers seem wedded to spending a disproportionate amount of their transportation dollars on transit, which sacrifices the interest of the vast majority of their commuters on the altar of wishing thinking.

They ought to indulge their fantasies on their own time and their own dime.

Hood is president of the John Locke Foundation.