An urban design firm is hoping to create the "world's greenest highway" by covering a major road in Dubai with gardens, trees, walkways and solar panels. The proposed 64-kilometer-long road, called the "Dubai Green Spine," would see the Sheikh Mohammad Bin Zayed Road, one of Dubai's main highways, enhanced with over 1 million trees and enough solar panels to power 130,000 homes. Dubai-based design firm URB says its road concept would help reduce carbon dioxide emissions by over 1 million metric tons per year, and help the city manage the needs of a population that's expected to grow from over 3 million today to nearly 8 million by 2040. URB's design aims to reduce city heat and improve air quality while offering a safe, attractive and accessible route for commuting and leisure. Green spaces would be combined with walking and cycling paths, and electric tram lines would have solar panels built directly into the tracks. Bus shelters and elevators would have rooftop solar panels, while garden-covered paths over the highway would make a walk from one side to the other easy and enjoyable. URB CEO Baharash Bagherian says the concept is about "proving that our streets can do more than facilitate car traffic; they can significantly enhance quality of life." He says the design takes a "human-centric approach" that prioritizes people and green spaces over cars. However, it takes a lot of water to grow plants in Dubai. CNN notes that the United Arab Emirates (UAE) already consumes around 550 liters of water per person every day, compared to an average of 310 liters in the US and 144 liters in the European Union. And most of the UAE's water isn't used for drinking — it's just needed to keep parts of the desert country green. With this in mind, URB's design includes drought-resistant plants and special soil that helps retain water. URB has also proposed designs for a 93-kilometer indoor cycling and walking "highway" called