Even as Google plans to test its fleet (车队) of self-driving cars on public roads this summer, its business model remains a bit of a mystery. By 2025, as many as 250,000 self-driving vehicles could be sold each year globally, according to a study by an industry research firm.

“Vehicles that can take anyone from A to B at the push of a button could transform mobility for millions of people,” said Chris Urmson, director of Google’s self-driving car project. For now, Google has no plans to sell any of its self-driving cars. They are strictly for research. But they will hit public roads this summer near Google’s headquarters in Mountain View, California. Previous testing has taken place only on closed courses.

The cars are built to operate without a steering wheel, accelerator (油门) or brake pedal. “Our software and sensors do all the work,” Urmson said. “The vehicles will be very basic — we want to learn from them and adapt them as quickly as possible — but they will take you where you want to go at the push of a button.” The prototype (雏形) is the first of a 100-car fleet the tech giant is building.

In the long run, Urmson sees a future of safer roads — the majority of auto accidents are caused by human error — and fewer traffic jams. Robotic cars could also shuttle people who can’t drive because of age or illness.

Google has said that self-driving cars could launch new business models in which people buy the use of vehicles they don’t own. The company has already tested other types of self-driving cars on public streets, including modified Lexus sport-utility vehicles, under a special permit program by the California Department of Motor Vehicles that requires a human driver at the controls.

The state has issued six other companies permits to operate such cars, including Delphi, Mercedes-Benz, Volkswagen, Tesla, Bosch and Nissan. The vehicles that will be tested on open roads this summer will have removable steering wheels, accelerators and brake pedals to allow “safety drivers” to take control if needed.

Mi Teleferico, Bolivia

Crossing the Bolivian capital of La Paz, the Teleferico is both the highest and longest city cable-car system on the planet. Built to relieve the city’s extreme road traffic, the three lines of this "subway in the sky" spirit the city’s 2.3 million citizens. At an altitude of 3,700 metres, you' ll feel the thrill of flying as you’re smoothly carried over entire neighborhoods and business districts—all for a ticket price that' s less than a dollar.

Everest Flights, Nepal

It is no easy work to climb the Everest, a mountain second to none at an altitude of 8 ,848 metres. Most of us know that we'll never move along the Hillary Step and overcome this mountain. Fortunately, a number of local airlines operating out of Kathmandu’s small domestic airport offer a glimpse of this glory for about a hundred dollars. In a few hours, you'll get into the heart of the Himalayas, getting close enough to snap a few fantastic photos from your window seat before circling back. No oxygen tank required !

Rocky Mountaineer, Canada

With select routes that lead through Banff and Jasper national parks as well as Lake Louise, Rocky Mountaineer provides a best opportunity to spot the wildlife of western Canada, including elk, bighorn sheep, and possibly even bears of the black, brown, and grayish variety. Rocky Mountaineer' s multi-day journeys include

breakfasts and lunches prepared by world-class chefs, B.C. wines, and an invitation to sit back, relax, and let the Rockies come to you.

Table Mountain Aerial Cableway, South Africa

Few places in the world have appeal like Table Mountain, the flat-topped monolith( 独石) that serves as the backdrop for most tourists' photos— and memories—of Cape Town. Completed back in 1929, the Table Mountain Aerial Cableway carries nearly one million sightseers to the summit every year,rising roughly 1,000 metres in fewer than five minutes.

Transport has a lot to answer for when it comes to harming the planet. While cars and trains are moving towards greener, electric power, emissions from air travel are expected to increase massively by 2050. If we want big green sky solutions, we need blue sky thinking. Fortunately, there's plenty of that happening right now, particularly the short-haul flights powered by batteries.

Harbour Air is the largest seaplane airline in North America, flying 30, 000 commercial flights in 40 seaplanes each year. Significantly, all Harbour Air routes last less than 30 minutes, making it perfectly fit for electric engines. “As an airline, were currently in the process of turning all our planes into electric airplanes. ” says CEO Greg McDougall. To make this happen, the airline has partnered up with MagniX to create the world's first commercial flight with an electric engine.

Making the skies electric isn't just good for the environment, it also makes sound financial sense: a small aircraft uses $400 on conventional fuel for a 100-mile flight, while an electric one costs $8-12 for the same distance, and that's before you factor in the higher maintenance costs of a traditional engine. There's also the added bonus that electric planes are just much more pleasant to fly in. No loud engine noise, no smell of fuel, just environmentally friendly peace and quiet.

While there has been real progress in the e-plane industry, the technical challenges that remain are keeping everyone's feet firmly on the ground. A battery, even a lithium one, only provides 250 watt-hours per kilogram; compare this to liquid fuel, which has a specific energy of 11, 890 watt-hours per kilogram. Carrying adequate batteries, however, would make the plane too heavy to get off the ground. In aircraft, where every bit of weight counts, this can't just be ignored.

The transition (过渡) from gas to electric in the automobile industry has been made easier by hybrids-vehicles powered by both fuel and electricity. Many believe the same patter could be followed in the air. Fuel consumption could be reduced as the electric component is switched on at key parts of the journey, especially on take-off and landing.

It's certainly an exciting time for electric flying. With companies like Harbour Air taking the lead, battery-powered planes, especially on short-haul journeys, are set to become a reality in the next few years.