2.8 The procurement team prepared a base case demand scenario, founded on the assumption, however unlikely, that the Agency would not require any changes to the services, other than those that were already part of a committed programme of future work to the national road network. The function of the base case was to establish a cost for the initial upgrade of core telecommunications systems and maintaining them over the length of the contract. This upgrade, representing the capital works in the first two years of the contract, would be financed by the contractor (Figure 9).
2.9 The Agency also had uncommitted plans for future work relating to the installation or removal of roadside devices that would require telecommunications services. These plans related to possible new road schemes, new traffic management schemes, extending the coverage of existing traffic monitoring devices and the installation of new types of devices. From the information obtained from across the Agency, the procurement team plotted out the maximum expected demand for the NRTS and this was approved by Agency staff responsible for telecommunications policy. The results were then used to prepare the high demand scenario (Figure 9). The Agency also used this scenario to establish the transmission capacity of the upgraded infrastructure.
2.10 The Agency designed the PPP so that the unitary charge would cover the contractor's cost of financing the initial upgrade of the telecommunications systems and maintaining them over the length of the contract (base case demand scenario) (Figure 9). For each functioning telecommunications service to the roadside devices, the contractor would also receive monthly a contractually set connection maintenance charge (Figure 9). This charge covers the contractor's cost of operating and maintaining the relevant service, over and above costs for the core network included in the unitary charge. If the Agency decided, in the future, to proceed with any of its uncommitted projects (captured in the high demand scenario), the contract was designed so that the Agency could order changes from a schedule of additional works priced during the competitive process (Figure 9). The Agency would therefore have certainty over the cost of variations for additional services. These services range from a connection to a single roadside device, to an extension to the overall coverage of the NRTS. The agreed prices were intended to capture the contractor's capital cost. Once the ordered additional works are completed, each new additional service would, thereafter, attract the monthly connection maintenance charge.