 Maglev) technology is around and tried. Improved vehicle technology (e.g. fuel efficiency, fuel technology) and vehicle design can offer substantial environmental benefits. Improved road/rail infrastructure management will be achieved through ICT (e.g. advanced vehicle guidance systems, network management systems), which will boost transport infrastructure productivity and have a marginal dampening effect on future infrastructure requirements. INFRASTRUCTURE TO 2030: TELECOM, LAND TRANSPORT, WATER AND ELECTRICITY - ISBN 92-64-02398-4 - © OECD 2006 4. KEY FACTORS DRIVING THE FUTURE DEMAND FOR SURFACE TRANSPORT INFRASTRUCTURE Security and safety concerns may run counter to environmental concerns. Additional security/safety costs will probably need to be built into rail systems to counteract security/traveler concerns. It is unclear whether (relative to air) there is a clear security/safety benefit for high-speed rail. Regional integration and international connectivity demand that rail systems be capable of meeting long-distance freight requirements (where rail still has a natural advantage), and that road systems are adequate for shorter-distance freight and passenger movements. History has shown that road transport linkages have been more important than rail, although our understanding (and decomposition) of traffic flows allows for a more sophisticated approach on a corridor basis. Investments in other transport infrastructures (air, ports, inland water) are also required, although there is some trade-off potential between air and land transport for medium-distance high-speed rail (with sufficient population density and gravity-interaction between nodes), and between inland water and rail for medium-distance freight movements. There is also considerable complementarity between land transport infrastructure and access to ports/airports, which act as respective international (long-distance) transport hubs. Road and rail connectivity to airports/ports is critical to growing international movements - and there is a