The National Motorway System is comprised of 7,100 km (4,412 mi). This system constitutes only 3 percent of the total roadways in the United Kingdom, but carries 33 percent of all traffic and 62 percent of freight. Compared to PPP activity in other sectors, PPP highway activity has been relatively modest. Figure 4 (see page 14) shows cumulative PPP investment since 1996 is near £4 billion.
Still, 10 percent of the National Motorway System is managed under PPP arrangements. The United Kingdom, however, is in the final stages of procuring its largest PPP project to date, the M25. Once closed, this will place 17 percent of the national system under PPPs. Local jurisdictions and the Department of Transport also have the authority to execute PPP arrangements, and both have exercised this authority.