Today’s post is by Leslie Valentine, an editor and writer at Environmental Defense.

When I visit friends and family in other places, whether it’s Portland or Los Angeles, Austin or New York City, I’m always struck by how traffic and commuting inevitably come up in conversation.

Those who live in the central core of a city are grateful they don’t have far to drive, or can walk or ’sub’ it to work. Others trade stories of commutes from hell, driving in bumper-to-bumper traffic on the main route into downtown. Everyone laments how it seems to be getting worse and worse every year in these lively, growing places.

Many growing cities and towns are traffic-choked and plagued by pollution. But population growth accounts for only a small share of increasing road traffic in recent decades.

What’s really going on is that Americans are driving more: We are taking more trips on motorways, making longer trips and driving alone more. More people live in car-dependent suburbs not conducive to walking or transit.

Sadly, incentives are skewed toward car use: "freeways" subsidized by general tax revenue, "free" parking paid for by employers, low mileage drivers subsidizing insurance costs for high mileage drivers, and countless policies favoring low density sprawl over infill mixed-use development. (Read more about our broken transportation system.)

But this has to change. We can’t keep building our way out of traffic jams and pollution with more roads and highways – it just doesn’t work. And the costs to our health and quality of life are too high. Our transportation experts at Environmental Defense have long studied the problems and are working on smart solutions. (Read more about solutions to traffic problems.)

One key is to use existing infrastructure much more efficiently. Incentives like congestion pricing and bus rapid transit lanes are two ways to get traffic moving. With tools like these in place, an existing highway can move more people more quickly with less environmental damage.

Says Environmental Defense regional director Andy Darrell: "Our country is growing, and we’ll always be building something new. The key is to build new communities in ways that decrease dependence on the traditional car and increase opportunities for walking, cycling and innovations like car-sharing, advanced vehicle technologies and new ideas for transit."

Take action: Help support transportation solutions. Earn points for your state for the personal actions that you pledge.

Editor’s note: We’re pleased to welcome Kira Marchanese to the Green Options blog! Kira, Director of Internet Communications at Environmental Defense, will be taking over for Jessica Bosanko, who’s moving on to other pursuits, including a wonderful-sounding trip with her partner to South America. We’re glad to have Kira on board, and very grateful to Jessica for her time and effort in contributing to Green Options.

Today’s post is by Tom Elson, from Environmental Defense’s Living Cities program.

If you spend time in a dense urban area like New York City, you know the frustrations of gridlocked streets: blocked intersections, horns blaring and tempers flaring. But there’s an invisible cost to traffic, too: the damaging health effects from breathing the air polluted by so many cars and trucks. Vehicles stuck in stop-and-go traffic produce up to three times the pollution of cars moving steadily.

But New York and other metro areas are on the road to clearer streets and clean air. Congestion pricing is one of the innovations that will help them get there.

The idea is simple: at times when the roads are busiest, drivers pay a premium to use them. Think of the way you buy an airline ticket. When you check fares, you get a wide range of prices depending on factors like when you want to fly and how many stops you’re willing to make. We know that flying at convenient times costs more, and we might take a red-eye to save money.

The concept is the same on the road. An electronic toll system collects the fee as drivers enter busiest sections. The system charges drivers more during the busiest times. Those who take mass transit or reschedule their trip can save money. (See more about congestion pricing.)

This isn’t a new idea. London started charging motorists to enter its central business district in 2003 and has seen traffic congestion cut by nearly a third. Sooty particles and nitrogen oxide pollution dropped by roughly a fifth each. Singapore, Stockholm and several cities in Norway have also reduced traffic, travel time and pollution.

The idea is still new enough in this country to raise questions, though, as last week’s debate in New York shows. Critics of congestion pricing worry that boundary neighborhoods – those just outside the pricing zone — will see an increase in traffic and cars trying to park there. Studies in London and Stockholm show otherwise. Those cities limited conflicts around the boundaries by issuing residential parking permits and creating park-and-ride facilities.

Commuters who live in areas with poor public transit fear not being able to drive – but revenue from collecting tolls is generally used to improve transportation. London, for example, raised hundreds of millions of dollars, which it invested in better transit such as new buses. Ridership rose dramatically, and bicycling increased. There, as in other places that have tried this system, skepticism gave way to enthusiastic support for the plan.

This year Mayor Michael Bloomberg embraced congestion pricing and unrolled a plan as part of his sustainability ‘greenprint’ for New York. A remarkably broad coalition of 140 civic, religious, health, business, labor and environmental groups supported the plan, despite strong opposition from some legislators. After intense negotiations, Bloomberg and state leaders agreed to consider a three-year pilot program.

New York City is one of nine finalists for $1.2 billion in federal grants to try congestion pricing and other traffic-busting incentives. Eight other cites — Atlanta, Dallas/Ft. Worth, Denver, Miami, Minneapolis, San Diego, San Francisco and Seattle — are vying for funds by proposing a variety of traffic-reducing tools, from tolling and parking management to express buses to telecommuting support. New York’s is the most comprehensive, with specific traffic-reduction goals leading to substantial cuts in air pollution and real public health benefits.

You can help! If you live in one of the cities trying to implement smart traffic policies, contact your elected officials and ask them to support congestion pricing.