French construction company Vinci has been chosen to build what will be the world's longest bridge, a span of 40 km that will link Bahrain and Qatar, the French weekly Le Point reported Wednesday on its website. The contract, which is worth $3 billion, was signed at the royal palace of Bahrain in the presence of Vinci's head Yves-Thibault de Silguy. The Qatar-Bahrain Causeway, as it has been named, will reduce the time of travel between the two states from the present five hours, via Saudi Arabia, to about 30 minutes. The Bahrain-Qatar causeway project is set to begin next year and is expected to be completed in four years. “The $3 billion causeway will have two lanes and one for emergency. The 25-mile causeway is ready for electric grid and oil pipe connections,” the Bahrain News Agency (BNA) reported Tuesday. This longest fixed link in the world, known as the Friendship Causeway, is expected to boost the trade exchange of both countries. “The volume of commercial exchange has increased 167 percent in the last seven years. Bahrain exports industrial and aluminium products, on the other hand imports iron bars and petrochemicals from Qatar,” the Bahrain news agency said. Construction on the bridge will begin after nine months of studies on the project have been carried out. Some 12,000 vehicles will be able to travel daily between Bahrain and Qatar when it is completed. Currently, the world's longest fixed bridge is the Lake Pontchartrain Causeway, which spans 38.4 kilometers.