Over the last 15 years, the lion's share of investments was for new construction while renovation and restoration work absorbed a small part of the pie. In the case of highways and roads, new construction consistently took up about 80% of investment budgets leaving 20% for renovating the road network. The rates for bridges and overpasses were similar to those of highways and roads during the 1990s, but renovation has been taking up an increased share in recent years, up to 30%.
Renovations are required not only for visible assets such as roads and bridges but also for more hidden ones like sewer and wastewater systems. In 2007, gross stock of investments in sanitary and storm sewers as well as wastewater treatment amounted to $59.9 billion or 21% of the five assets included in this study. In the 1990s, more than 90% of these investments were for new infrastructure while an increasing share was allocated to renovation and restoration in recent years.