Similarly, even in a context of overall paucity of roads, efforts to increase connectivity through road infrastructure are likely to have the most impact when targeted to those regions w'here industrial activity' is more easily facilitated. The relationship between infrastructure and growth can therefore take the shape of an inverted “U” curve, where at initial stages, low or no infrastructure has no impact on growth, until after a threshold where additional infrastructure will contribute to sharp rises in maiginal growth, until economies reach a level of infrastructure provision that is almost complete. From that point on, additional infrastructure investments have once again low or no impact on economic growth.