Road surface - online puzzles

A road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, cobblestone and granite setts were extensively used, but these surfaces have mostly been replaced by asphalt or concrete laid on a compacted base course. Road surfaces are frequently marked to guide traffic. Today, permeable paving methods are beginning to be used for low-impact roadways and walkways. Pavements are crucial to countries such as US and Canada, which heavily depend on road transportation. Therefore, research projects such as Long-Term Pavement Performance are launched to optimize the life -cycle of different road surfaces.