New technology

New technologies, especially those that benefit the environment, will also bring greater benefits in the long term.

The first photovoltaic road, in which current is generated when the surface is exposed to light, was completed in Jinan, Shandong province, in November, and marked a breakthrough in highway construction.

Zhang Hongchao, a professor of road engineering at Shanghai's Tongji University who developed the core technology for photovoltaic road construction, said highways, including expressways, will be developed into ecological "smart ways", while photovoltaic roads are a new form of eco-friendly tech.

"The idea of building a photovoltaic road was initiated by a tech amateur in 2006," he said. "I've done research since 2013 after being inspired by the idea back in 2009."

He said the photovoltaic road project built in Shandong attracted investment totaling 50 million yuan from Qilu Transport Development Group in Jinan about two years ago.

The 2-km-long road opened to traffic in December. It was later reported that if the hard shoulder in Shandong province, which covers 26,000,000 square meters, was replaced with a solar-powered one, more than 6 billion kilowatt hours could be generated a year.

It is hoped the road will provide extra electricity for the national grid, and may even charge electric vehicles as they travel along it.

However, the new-tech road has triggered controversies over investment and economic benefits.

Zhao, the professor from Beijing Jiaotong University, is critical of the photovoltaic road.

"The investment is much greater than the average for highway construction, while the practical performance has yet to be tested," he said.

"In addition, the economic returns are also hard to meet, and will put a greater financial burden on the government and highway operators."

Zhou, from the Shanghai Urban Construction Design and Research Institute, said eco-friendly materials may be a better entry point for new-tech highway construction.

"Solar energy and ecological materials from steelmaking or coal-fired waste are ideal materials," he said. "The solar-powered road experiment still has a long way to go."

However, Zhang, from Tongji University, said such roads have a bright future.

"It is not whimsy, but a necessary stage of new tech exploration," he said. "What we are stressing is eco-friendly technology in highway construction, which is an objective not only for us, but a goal for engineers worldwide."