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Suggested Citation:"Summary." National Academies of Sciences, Engineering, and Medicine. 2022. Systematic Approach for Determining Construction Contract Time: A Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/26537.
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Page 1
Page 2
Suggested Citation:"Summary." National Academies of Sciences, Engineering, and Medicine. 2022. Systematic Approach for Determining Construction Contract Time: A Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/26537.
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Page 2
Page 3
Suggested Citation:"Summary." National Academies of Sciences, Engineering, and Medicine. 2022. Systematic Approach for Determining Construction Contract Time: A Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/26537.
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Page 3

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1   Getting a construction project done on time is a major performance indicator that state departments of transportation (DOTs) constantly monitor. However, many DOTs continue to struggle to meet the schedule performance target of their highway projects. Determining construction contract time is crucial in the project development process, not only because it directly affects a key performance indicator for the agency but also because it affects contractor selection, construction costs, construction quality, safety, and public satisfaction. Unreasonably short or long construction contract times can create negative effects such as high bid prices, lack of qualified bidders in bidding, poor work quality, claims and disputes, prolonged inconvenience to the traveling public, lack of innovations, increased administra- tion costs, and safety issues. Recognizing the critical importance of a reasonable contract time, most DOTs have devel- oped a formal procedure for establishing contract time, and general principles, methods, and tools have been included with the 2002 Federal Highway Administration (FHWA) guid- ance. This guidebook was developed to address the need for systematic and specific contract time determination (CTD) procedures for different contracting methods, such as design- bid-build (DBB) projects, urban projects with incentive provisions, and projects using alternative project delivery methods (APDMs). The guidebook also addresses contract time’s relationship to risk management and the post-construction contract time evaluation and feedback loop for continuous improvement of the CTD procedure for future projects. The guidebook consists of six chapters. Each chapter provides a step-by-step and easy-to- follow procedure that includes background information; a general description of the overall process; and detailed guidance for each step, such as possible sub-steps and descriptions, required documents and information, expected outcomes, and methods and tools. Chapter 1 provides a more detailed orientation to the guidebook. Chapter 2 is a CTD guide for typical DBB projects. As contract time types (e.g., working day or calendar day) affect the CTD process, the detailed discussions and information (i.e., defini- tion, applicability, benefits, and weaknesses) of different contract time types are synthesized and provided to support the selection process of contract time type. The proposed procedure also differentiates CTD from project duration estimation (PDE). Although PDE is used for establishing an estimate of contract time based on a project’s characteristics and design infor- mation, external factors (e.g., political commitments, coordination with other projects, and budget) can impose milestones and completion date constraints on the project and result in an actual contract time that differs from the estimate. In CTD, the PDE and those constraints become two primary determinants for finalizing the contract time. Detailed guidelines on S U M M A R Y Systematic Approach for Determining Construction Contract Time: A Guidebook

2 Systematic Approach for Determining Construction Contract Time: A Guidebook each component and comparisons between them are provided in the chapter. Although the approach for making comparisons is similar among DOTs, PDE practices may vary significantly. Chapter 2 also analyzes and summarizes various scheduling methods in terms of advan- tages and disadvantages to help contract time developers select the most appropriate method. A DOT can easily compare its current practice with the state of the practice described in the guidebook and decide whether improvements are necessary. The impacts of advanced tech- nologies that are gradually being adopted in the highway construction sector (e.g., automated machine guidance on PDE) also are discussed, along with proposed methods for quantifying the effects on construction time. For high-volume urban projects where work zone mobility and safety are seriously dis- rupted during construction, project costs usually become a secondary concern because of the urgency of early completion and the minimization of public inconvenience. DOTs are motivated to accelerate construction using innovative alternative contracting techniques (ACTs) to reduce the negative impacts. Also, other options to accelerate construction (e.g., different working calendars, lane closure scenarios, traffic management plans, and mobility impacts) are frequently considered concurrently with ACTs. These typical characteristics of urban projects in heavy traffic areas necessitate some adjustments to traditional DBB projects’ generic CTD guidelines for urban projects. Chapter 3 provides detailed CTD guidance for those schedule-driven urban projects. Chapter 3 also provides a discussion of the characteristics of major ACTs to help agencies determine the appropriate ACTs for various kinds of projects. DOTs have increasingly used APDMs for their projects. APDMs typically seek to compress project delivery time by engaging contractors early in the project development. This early involvement significantly influences project contract time, which creates the need for APDM- specific CTD procedures. However, guidance for those procedures is not currently available at most DOTs. Chapter 4 fills this gap by providing guidance for APDM projects. The guidance includes work packaging and preconstruction period estimating, which are unique in APDM projects as compared to typical DBB projects. Breaking down a project into multiple work packages allows some construction phases to begin as soon as the package’s design plans are released rather than waiting until the overall design is 100 percent complete. Chapter 5 provides guidance on how risk assessment and mitigation principles can be incorporated into CTD processes. As mentioned earlier, PDE and milestone and completion date constraints are two primary determinants for contract time. PDE is a method-driven approach. Its resulting estimate is always fraught with uncertainties because of a lack of information and various influential factors on project duration. Accounting for these uncer- tainties allows for a more reliable and accurate comparison between the two determinants in establishing contract time. As risk assessment is costly, quantitative risk analysis is only proposed for large and complex projects using probabilistic methods for quantifying the uncertainties. For small projects, overall duration contingencies from qualitative risk analysis are probably sufficient. Most DOTs recognize post-construction review meetings as a primary mechanism to collect lessons learned (LLs) for future projects, but the DOTs may not have any formal post-construction feedback protocol. Chapter 6 presents a post-construction contract time feedback loop and a corresponding step-by-step procedure, demonstrating how the flow of various types of information generated in each project phase can be collected and used for determining the contract time of a future project. Metrics and procedures also are developed for evaluating CTD methodology effectiveness.

Summary 3   The guidebook also provides more than 20 methods and tools to help DOTs enhance their CTD practices. These methods and tools have been integrated into the MS Excel (spreadsheet- based) “CTD4HP Toolkit.” Along with a User Guide, the CTD4HP Toolkit is available for download from the NCHRP Research Report 979 webpage at www.trb.org. The toolkit can assist DOTs in applying the proposed procedures described from Chapter 2 to Chapter 6 in this report. For example, the general tool for production rate estimation (GEN-PRET) can be applied by any DOT that maintains or is willing to obtain production rates of past projects to establish a state-specific automated tool for estimating production rates. The “From PDE to CTD” tool (PD2CT) can help determine contract time given a project duration estimate in working days, considering the effects of multiple influential factors. The “project duration estimation methods” and “project-specific production rates” tools provide various methods and options to accommodate the varying CTD practices of DOTs.

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Contract time affects the cost of construction, traffic disruption and public inconvenience, the economic impact of projects to the surrounding areas, and schedule risks.

The TRB National Cooperative Highway Research Program's NCHRP Research Report 979: Systematic Approach for Determining Construction Contract Time: A Guidebook provides state departments of transportation guidance for producing consistently credible, reliable, and defensible contract time estimates.

Supplemental to the report is NCHRP Web-Only Document 298: Developing a Systematic Approach for Determining Construction Contract Time, a spreadsheet-based Toolkit, a Technical Memorandum, and a Presentation.

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