The advent of World War II halted sign modernisation efforts across Europe however, and governments, fearing that invading forces or enemy spies could use such signs to navigate, removed all direction signs from the road networks. The end of the war was however used as an opportunity by many European nations to redevelop direction signs. The construction of high speed motorways meant that traditional road signs were no longer practical, and so new, modern signs with bold, sans serif typefaces and diagrams indicating lanes and sliproads ahead were developed. The British Worboys Committee went even further, and created signs with detailed maps of junctions. Such signs have been in use almost unchanged for over half a century.