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.

The author of today’s post, Sheryl Canter, is an Online Writer and Editorial Manager at Environmental Defense.

Hydrogen fuel cell vehicles got a big boost when President Bush made them part of his 2003 State of the Union address:

Tonight I’m proposing $1.2 billion in research funding so that America can lead the world in developing clean, hydrogen-powered automobiles… With a new national commitment, our scientists and engineers will overcome obstacles to taking these cars from laboratory to showroom, so that the first car driven by a child born today could be powered by hydrogen, and pollution-free.

That generated a lot of interest in hydrogen cars! So what are they, and can they become mainstream in the next 20 years?

Honda FCX fuel-cell car.

Hydrogen fuel cells take in hydrogen and oxygen, and put out water, heat, and electricity - no pollution at all.

Sounds good, but there’s a catch - producing the hydrogen fuel can itself generate significant greenhouse gas emissions and other pollutants. And unfortunately, that’s not the only serious hurdle.

Honda is the first company to put a fuel cell demonstration car into the hands of ordinary consumers. Yet as Steve Ellis, Honda’s Manager of Fuel Cell Vehicles, told me hydrogen-powered cars are not likely to be mainstream for another 10 to 20 years. Many industry analysts put the number at well over 20 years, and some think it will never fly. All agree it’s not a near-term solution.

Chevrolet Sequel fuel-cell car.

Joseph Romm, in "The Hype about Hydrogen, notes five main problems with hydrogen cars as they currently stand:

• They are extremely expensive, currently costing around $1 million (for example, the GM SequelHonda’s FCX). Most of this cost is in the fuel cells. If history is any guide, it will take decades for the cost to come down sufficiently.

• On-board fuel storage is a huge problem - literally - since at room temperature and pressure, hydrogen takes up 3000 times more space than an energy-equivalent amount of gasoline. There are several ways to store hydrogen, but all known approaches are complex and costly. Storing hydrogen as a liquid isn’t practical because it takes so much energy to liquefy and then convert back to gas. Storing it as compressed gas requires 300 to 600 times atmospheric pressure, and even then the tanks take up more than five times the space of a gasoline tank.

A National Academies study [PDF] noted, "In even the best case of improved compression efficiency and high pressure on-board tanks, the energy, space, cost, and weight penalties are formidable." It goes on to recommend that the U.S. "halt efforts on high-pressure tanks and cryogenic liquid storage" since "neither approach can reach DOE targets for energy density". A Department of Energy review reached a similar conclusion.

• There are serious safety issues with hydrogen fuel since it’s among the most flammable substances known. It is vastly easier to ignite than gasoline, and leaks are much harder to detect and control. A cell phone or flashlight could ignite it, as could static electricity or an electric storm a few miles away.

Russell Moy, former Project Manager for hydrogen storage at Ford Motor Company, wrote about this in an article for the Energy Law Journal [PDF]: "Industrial experience has shown that 22 percent of hydrogen accidents are caused by undetected leaks, despite the standard operating procedures… of specially trained hydrogen workers. With this track record, it is difficult to imagine how the general public can manage hydrogen risks acceptably." Chemical Engineer Reuel Sinnar put it even more strongly [PDF]: "A hydrogen car as presently envisioned is a potential suicide bomb that cannot be detected by any of the standard methods that detect explosives."

• Producing hydrogen is expensive and energy-intensive [PDF]. The same energy currently used to create electricity would be used to create hydrogen, and today this mostly involves the use of fossil fuels (see House testimony of Dr. John Heywood of MIT).

Current methods using natural gas produce significant heat-trapping emissions, and there is a serious question of whether a renewable fuel used to create hydrogen wouldn’t be better used to replace electricity now generated from coal, since generating electricity is much more efficient than producing hydrogen power for vehicles.

• There’s no fueling station infrastructure for hydrogen. Building a hydrogen fuel infrastructure will be very expensive. A National Renewable Energy Laboratory report estimates the cost at $837 million [PDF]. Others say it could be tens of billions of dollars.

Companies hesitate to build something so expensive when there are no cars to use it. Similarly, automakers are reluctant to manufacture hydrogen cars when there’s no infrastructure, because consumers won’t buy them if they can’t fuel them. It’s a classic "chicken-and-egg" problem.

There’s another obstacle to infrastructure. Ideally, hydrogen would be produced in a central location so carbon emissions from its manufacture could be efficiently sequestered. But that isn’t set up yet, so initially the hydrogen would be created locally. No one wants to invest large amounts of money in an infrastructure that will be abandoned.

All these problems may be solvable, but it will take time. And you can’t necessarily trust the automakers’ predictions. In 2001, our automobile expert, John DeCicco, Ph.D., wrote an in-depth review of fuel cell vehicles [PDF] for the Society of Automotive Engineers. In it he noted that "Several automakers have pledged the introduction of fuel cell vehicles, including buses, by 2003-2005." It’s 2007, and beyond a few demos I don’t see them yet! Dr. DeCicco considers the hydrogen car an "utterly speculative proposition."

Maybe we’ll have hydrogen fuel cell vehicles by 2030, but in 20 years, who knows? Perhaps some new and better technology will come along, and research into hydrogen power will be abandoned. None of us can know which technology will be the future, but we do know this: the world can’t wait 20 years to reduce carbon dioxide emissions from vehicles. So while the hydrogen car is worth researching for the long term, the heavy emphasis placed on it by the Bush Administration is ill-considered.

So if you’ve been waiting for hydrogen cars to let you off the hook for buying a fuel efficient car and driving it smartly, time to reconsider! It’s the same old smart driving tips for now.

The author of today’s post, Sheryl Canter, is an Online Writer and Editorial Manager at Environmental Defense.

Plug-in Hybrid Electric Vehicles, or PHEVs, have been in the news a lot lately (and here on Green Options, too!). It’s an appealing idea - virtually no emissions, just plug in your car at night and go. Plus, the batteries that drive them could store electricity for homes and offices. When cars are parked and plugged in, the electric utility could draw on stored battery power during times of peak demand (with compensation to the car owner).

But will plug-in cars really be ready for widespread use by 2010?

Reading the news, you might think that PHEVs are just around the corner. Toyota just displayed a plug-in version of its Prius. A recent study by the Electric Power Research Institute (EPRI) and the Natural Resource Defense Council (NRDC) says that if plug-in cars are in widespread use from 2010 to 2050, the reduction in greenhouse gas emissions could be dramatic.

Certainly people are trying to make it happen, spurred by inventor/advocates such as Felix Kramer of CalCars.org and others. The Austin City Council has launched a $1 million campaign to promote plug-ins. Google’s philanthropic arm is donating $10 million towards the development of the technology. General Motors made a splash with its Chevy Volt concept in January. Ford has joined the party with a plug-in prototype of its Edge SUV.

But as our automotive expert John DeCicco points out, there are some daunting technical issues. In a briefing before the U.S. Senate [PDF], Advanced Automotive Batteries president Menahem Anderman estimated that plug-ins won’t be generally available for another 10 years. Honda manager John German, also in Senate testimony [PDF], said that the problems with plug-ins were so difficult that Honda wasn’t even going to try.

So what’s going on? Are plug-ins around the corner, 10 years away, or not realistic at all?

The bugaboo is the battery. Here’s a summary of the problems, based on Anderman’s analysis:

1. The plug-in battery will be about 3 to 5 times the size of today’s non-plug-in hybrid batteries, essentially filling the cargo space of an average sedan.
   The weight of this battery will add 200 to 300 lbs. to that of the car, putting a drag on performance and efficiency.
2. The lithium batteries needed to provide adequate performance for plug-ins raise a serious concern about hazardous failure, such as a fire in a home garage, because they need much deeper, full charging than the smaller batteries of today’s hybrids, which are always kept at an intermediate state of charge.
3. The cost of this plug-in battery (at pack level) to carmakers, using present technology, will be 3 to 5 times the average cost of today’s hybrid batteries, i.e. around $5,000 to $7,000 per pack.
4. The life of any battery technology, lithium or otherwise, when used in a plug-in car is not known. There’s a good chance that battery life will be short, meaning costly replacements over the life of a vehicle.

John German points to market problems, as well. He says that unless battery prices drop considerably, the vehicles will be too expensive for broad acceptance. So Honda has instead chosen to focus on hydrogen fuel cell technology.

German closes his statement with some good advice about how the government can help:

It is impossible to predict the pace of technology development and when breakthroughs will or will not occur. Accordingly, technology-specific mandates cannot get us where we need to go. In fact, previous attempts to mandate specific technologies have a poor track record, such as the attempts in the 1990s to promote methanol and the California electric vehicle mandate. The primary effect of technology-specific mandates is to divert precious resources from other development programs that likely are more promising. If there are to be mandates, they should be stated in terms of performance requirements, with incentives and supported by research and development.

So will plug-in hybrids eventually become mainstream? Possibly, but only with sufficient investment in the development of battery technology. Since we can’t know for sure which technologies will work out, it’s best to push ahead on all fronts - including making better use of the technologies already at hand - and not put all our eggs in the plug-in basket.

By John DeCicco, Environmental Defense automotive expert

American cars and light trucks are a huge source of global warming pollution. U.S. autos emit more than 333 million tons of carbon dioxide each year, roughly one-fifth of the nation's total carbon dioxide emissions. In 2004, U.S. cars and light trucks traveled 2.7 trillion miles. That's equal to 10 million trips from the earth to the moon.

Any serious effort to fight global warming must include cutting auto emissions.

The good news? There are a lot of simple steps you can take to cut your car's emissions – and when you cut your emissions you'll also be saving yourself money at the pump.

Before we get to the tips, I can't resist reminding you that your most important leverage comes when you decide to buy a car (or not!). Unless you live in an urban area with good walking, biking and transit options, you're likely to be one of the over 200 million Americans who rely on a car. The best advice is simple: choose the most fuel-efficient vehicle that meets your needs and fits your budget. Choosing your car as if the health of the planet depends on it means giving fuel efficiency greater priority than higher horsepower, extra size and all the "creature comforts" that most auto advertising seduces us to think are oh-so-important. Yahoo!'s Green Ratings are an easy way to compare cars.

But most of the time, of course, we are using the car we have, and there are in fact lots of ways to make the best of it, environmentally speaking. Here are some tips to get you started:

Drive efficiently

• Lighten up! Carrying around an extra 100 pounds in your car reduces your fuel economy by up to two percent. Take with you only what you need and be sure to place luggage inside instead of in the trunk or on the roof to minimize drag and maximize your mileage.
• Take it easy. Nine out of 10 doctors and engineers agree—aggressive driving wastes fuel, not to mention increases stress and accidents! Rapid acceleration and braking reduces gas mileage and can burn an extra 125 gallons of gas per year. Even if the person driving in front of you hasn't seen our tips list, hold your horsepower and keep your cool. And keep your distance, too: tailgating means more fuel-wasting braking, and is one of the worst safety hazards as well.
• Keep it slow. In highway travel, exceeding the speed limit by a mere five mph results in an average fuel economy loss of six percent. You're not on the NASCAR circuit. This is commuting, not racing.
• Don't be an American idle. Idling for more than 10 seconds uses more gas and emits more global warming pollution than restarting your car! Also, the best way to warm up a car in winter months is to drive it. When the temperature is below freezing, give it 30 seconds—that's all you need.
• Hot fun in the summer time. Air conditioning can decrease your fuel efficiency by as much as 12 percent in stop-and-go traffic, so consider cracking the windows. But at high speeds, driving with the windows open can decrease the overall efficiency of the vehicle. At higher speeds, you can use the vents to get a good air flow. On the hottest days keep your AC on low.

Maintain your car

• Don't be tune deaf. Keeping your engine properly tuned can save you up to 165 gallons of gas per year. Checking spark plugs, oxygen sensors, air filters, hoses and belts are a few examples of maintenance that can result in big savings. (Energy Information Administration’s U.S. Retail Gasoline Prices)
• Keep up the pressure. Low tire pressure wastes over two million gallons of gasoline in the United States—every day! Save about a tank of gas a year by keeping your tires properly inflated. And make sure to have your tires correctly aligned to maximize fuel economy.
• Go grease lightning. Thicker than required oil will reduce your gas mileage, because it takes more energy to push through thick oil than it does through thinner oil. Check your owner's manual for the recommended weight, and ask for it specifically when you get your oil changed.

Drive less

• Combine trips. Cutting a 20 mile trip out of your schedule each week can reduce your global warming pollution by more than 1,200 pounds a year and save you over $100 in gas expenses.
• Telecommute once a week. If all commuters worked from home just one day a week, we could save 5.85 billion gallons of oil and cut over 65 million metric tons of carbon dioxide each year.
• Share a ride. Carpool and use public transportation when possible. If you share rides and use other means to get to work, you'll save yourself money, reduce congestion on the roads and cut your global warming pollution.
• Just park it. And keep it there. If you’re going to several stores in the same strip mall, don’t move your car. Walk.
• Gotta wear shades. In summer, park in the shade. Use windshield shades to keep summer heat from baking your car and to help keep frost away in the winter.
• Move your feet. Walk, ride a bike or take the train when your car isn’t needed.
• Avoid the rush. Plan trips during off hours when fewer cars are clogging the roads.