Cross-asset allocation involves the distribution of resources among road investment programs in order to realize the strategic objectives of the organization responsible (see paragraph 18.104.22.168). An investment program may refer to any works program intended to maintain or improve asset condition, but also to impact other performance areas such as safety, mobility or sustainability. In general, road attributes modifiable through investment programs may be designated as “drivers for renewal / maintenance” (AM4INFRA 2019).
The allocation of resource among investment programs is a complex task that starts with determining optimal solutions for single assets / operational issues. Many organizations have implemented advanced management systems for pavements, bridges and road safety, but only a few of them have appropriate tools for other areas. Since asset management implies assessing the level of service of a road network as a whole, the next step should be allocating constrained resources across the various investment programs. A question immediately arises: what (consistent) measures should be used to compare the benefits of the different programs among them?
During the 2009-2012 cycle, the PIARC technical committee on asset management carried out a study to identify the main approaches used by member countries to allocate resources among different assets (PIARC 2012-b). The study showed that the most common distribution method remained a percentage split of budget based on historical allocation. Nevertheless, road organizations already had envisaged the future use of more formal methods such as risk ranking, comparison of economic indicators (NPV, BCR and IRR), and multicriteria analysis.
Later on, the implementation of holistic asset management in a number of countries worldwide, led to the application of increasingly sophisticated procedures for coordinating, prioritizing and optimizing all maintenance activities on the different asset classes, as found by PIARC technical committee on asset management that worked through the 2013-2015 cycle (PIARC 2016). The study carried out by this committee quotes a Trans-European ENR research project known as PROCROSS, which identified three basic approaches to cross-asset allocation used in European countries (ENR 2012): bottom-up, top-down, and a combination of these. According to the project, all three approaches are valid and consistent in finding an optimum solution based on existing preconditions
A general description of the approaches identified by PROCROSS is presented in paragraph 22.214.171.124.