1 PUBLIC TRANSPORTS ROADS Road planning Engineers, surveyors and construction experts are involved in studying what type of road should be made in a certain area, depending on the amount and type of traffic the road will be likely to support. Detailed land surveys are carried out to determine the curvature, the and the itinerary of the road. Other factors that planners must consider include , , , and how the new road will affect the community and the environment. Finally, the road project must be approved by local or government authorities according to the investment for the of the infrastructure. gradient cost of materials availability safety allocated implementation Road construction The first part of the construction operations is one of the most important: . Huge must be used to create a solid for the road to be built on. earthwork earth-moving machines 1 foundation and move around to create a level surface that will support the road, is added in and machines roll over the surface to compact and it. and are installed at this early stage, so that rain will drain away from the road surface and make it easier for vehicles to travel in storms. Bulldozers graders gravel layers flatten Drains sewers Materials The most common materials used for roads are asphalt or concrete. paving is a mixture of aggregates such as , sand, . In order the aggregates into a cohesive mix, a is used. is the most common binder, although nowadays, a series of bio-based binders are also under development with the aim of minimising the environmental impact of the roads. After the asphalt is heated to about 150°C, it is transported to the construction site, where workers spread and compact it onto the foundation already in place. Asphalt rock crushed gravel to bind binder Bitumen uses sand and crushed rock, but it is held together with cement. Once the road is finished, it must be inspected. The next priority is . Without regular maintenance, roads can rapidly fall into bad condition. Concrete maintenance WARM UP The Romans were masters in constructing roads. Do you know the names of any ancient Roman roads in Italy and where they go to? MORE Trucks, cranes, asphalt mixers, road rollers are other types of construction equipment used to build roads. 1 DO What is bitumen made from? Use the net to get information. 1