Options and Development Phase Costs: minimum, most likely and maximum cost estimates were then established for the options and development phases (see and Table 4.1 below); The Cost of Risk: thirdly, construction were identified. The cost of these risks was estimated and added to minimum, most likely and maximum estimates; Inflation, Programme Risk and Range Narrowing: further allowances were then added for programme risk and assumed future inflation prior to range narrowing between minimum and maximum estimates to produce final minimum, most likely and maximum estimates. Outturn costs have been produced using the Highways Agency’s Cost Estimation Summary Spreadsheet (CESS) and Range Estimation Tool (RET). The CESS provides a breakdown of costs incurred throughout scheme life from the options phase through to completion of construction and handover, in line with the HA’s Project Control Framework, as shown in Error! The RET is used to add allowances for inflation and programme risk Reference source not found.. and to narrow the range between the minimum and maximum estimates. Figure 4.1: HA Project Control Framework Phases and Stages We have presented costs to show the split between those costs attributable to the main crossing structure and all other costs involved with linking crossing structures to the existing road network. The HA provided assumptions to attribute the distinct cost elements (defined below) between the main crossing and other road network connections. Composition of Capital Our estimates of capital costs comprised consideration of the cost elements shown in Table 2. Table 4.1: Capital Cost Definitions and Assumptions Time Cost Item Description Source incurred Options Phase This includes the cost of 2013 - 2016 established from identification of various scheme AECOM database of options and selection of a comparable projects. preferred option. Designs Costs reviewed and considered within the options revised in discussion would be produced at a more with Highways Agency. detailed level than those used to inform this study. A preferred option would be selected following public consultation process. Development Preliminary design and statutory 2016 - 2019 Cost established phase, preliminary procedures to authorise a chosen from AECOM database design scheme, including statutory of comparable projects processes. Development Land costs including land 2020 - 2021 Cost rates established phase, land purchase, blight and compensation from AECOM database of comparable projects. Construction The costs of approach roads and Cost rates established roadworks connections to the existing road from AECOM database network, junctions and side road of comparable projects, alterations reviewed by Highways Agency.
Options and Development Phase Costs: minimum, most likely and maximum cost estimates were then established for the options and development phases (see and Table 4.1 below); The Cost of Risk: thirdly, construction were identified. The cost of these risks was estimated and added to minimum, most likely and maximum estimates; Inflation, Programme Risk and Range Narrowing: further allowances were then added for programme risk and assumed future inflation prior to range narrowing between minimum and maximum estimates to produce final minimum, most likely and maximum estimates. Outturn costs have been produced using the Highways Agency’s Cost Estimation Summary Spreadsheet (CESS) and Range Estimation Tool (RET). The CESS provides a breakdown of costs incurred throughout scheme life from the options phase through to completion of construction and handover, in line with the HA’s Project Control Framework, as shown in Error! Reference source not found.. The RET is used to add allowances for inflation and programme risk and to narrow the range between the minimum and maximum estimates. Figure 4.1: HA Project Control Framework Phases and Stages We have presented costs to show the split between those costs attributable to the main crossing structure and all other costs involved with linking crossing structures to the existing road network. The HA provided assumptions to attribute the distinct cost elements (defined below) between the main crossing and other road network connections. Composition of Capital Our estimates of capital costs comprised consideration of the cost elements shown in Table 2. Table 4.1: Capital Cost Definitions and Assumptions Cost Item Description Time incurred Source Options Phase This includes the cost of identification of various scheme options and selection of a preferred option. Designs considered within the options would be produced at a more detailed level than those used to inform this study. A preferred option would be selected following public consultation process. 2013 - 2016 established from AECOM database of comparable projects. Costs reviewed and revised in discussion with Highways Agency. Development phase, preliminary design Preliminary design and statutory procedures to authorise a chosen scheme, including statutory processes. 2016 - 2019 Cost established from AECOM database of comparable projects Development phase, land Land costs including land purchase, blight and compensation 2020 - 2021 Cost rates established from AECOM database of comparable projects. Construction roadworks The costs of approach roads and connections to the existing road network, junctions and side road alterations Cost rates established from AECOM database of comparable projects, reviewed by Highways Agency.
design-and-costing-report.docx