Believe it or not, there are ways to reduce traffic congestion, even if most politicians and planners haven't been eager to adopt them. Here are five potent suggestions, ideally done not alone but in conjunction with one another:

Creative construction. Expanding capacity doesn't always mean adding lanes to congested roads, although that's often a good idea as well. In densely populated Southern California, portions of the highway network are elevated well above the ground, including the Harbor Transitway approaching downtown Los Angeles. In Texas, San Antonio and Austin have double-decker freeways as well. In 2006 Tampa opened its cross-town expressway, an elevated road built in the median of an existing four-lane highway.

If going up is a problem, you can also go down. Australia has done an effective job of using tunnels to connect highways while preserving neighborhoods, an excellent alternative to destroying businesses and homes.

Smarter management. Building new capacity can get you only so far. The Federal Highway Administration estimates that half of all congestion could be eliminated simply through better management of the existing road network. Among other approaches, this could mean metering freeway ramps, turning two-way streets into one-way streets, and improving traffic light coordination. According to the Institute of Transportation Engineers, better-coordinated lights can reduce stops by as much as 40 percent, thereby cutting gas consumption, emissions, and travel times.

Market pricing for roads. One especially fruitful idea is high-occupancy toll (HOT) lanes, which allow drivers who put the highest priority on quick commutes to pay a premium for uncongested lanes. These have been built in Denver, Houston, and-yes-Minneapolis, among other cities. In Atlanta several private companies have submitted plans to build new HOT lanes on their own dime. During rush hour, the congestion difference between the special lanes and the regular lanes can be the difference between going 15 miles per hour and doing 65.

Areas with lots of car pool lanes could convert those to HOT lanes, add some connectors, and create a congestion-free HOT network. Transit boosters, take note: It would be easy to tweak the arrangement to guarantee bus riders a speedy trip too.

Market pricing for parking. On 99 percent of our trips we park for free, thanks largely to the minimum parking requirements embedded in our zoning codes. Eliminating those requirements would allow market forces to reflect the true cost of parking. Instead of adhering to arbitrary regulations that often order more spaces than necessary, developers would have greater flexibility to build only the number of spaces that is needed. Workplaces would be more likely to adopt parking cash-out programs, which give employees who do not drive to work a share of the money that otherwise would have gone toward parking costs. Employees would be more likely to work from home.

Market pricing for parking would reduce traffic too. If drivers had to pay the full cost of parking, they might be less inclined to take certain trips, thus putting a dent in congestion. More important, when parking is scarce but free (or underpriced), drivers have an incentive to keep the spots as long as possible. When it is scarce but costs money, drivers are less likely to dally. One additional result: Other drivers have less need to circle around and around, hoping eventually to spot an empty space.

Traditional parking meters can be notoriously inconvenient, but they aren't the only way to pay for parking. Aspen, Colorado, uses a variety of new technologies, including personal in-vehicle meters. The town determines its parking rates by zones; prices are highest in the city center and drop the further you are from the core. Motorists simply park, type in the number of their parking zone, turn on the meter, and hang it from the rearview meter. A timer deducts the prepaid amount until the driver returns. No one has to hunt for loose change.

Privatization. We're much more likely to adopt ideas like the above when roads are built and managed by companies responding to market incentives, not by government officials responding to planning fads and political clout. Private companies can create and operate highways using toll revenues as a funding source. The government can also convert existing roads to privately managed systems to allow improvements and expansions of the existing network.

For a spectacularly successful example, consider the 407 Electronic Tollway outside Toronto. This innovative road isn't fully private, but it was built by a private company (the Canadian Highways International Corporation) and is now managed by another private company (407 International) that bought a 99-year lease from the government of Ontario. Yet another company, Hughes Electronics, equipped it with an electronic toll-collecting system that eliminates toll booths and the congestion they can cause.

This solution is excerpted from an article of the same name originally published in Reason Magazine in April, 2007.