New approach to developing conceptual cost estimates for highway projects

Mounir El Asmar, Awad S. Hanna, Gary C. Whited

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Developing a reliable project cost estimate is a challenge for any state highway agency (SHA), especially at the conceptual stage. A conceptual estimate is defined in this paper as the estimate prepared at the point at which only 30% of the design is complete. This paper describes a statistical approach to producing a reliable conceptual cost estimate when few project design details have been finalized and many assumptions still form the basis of the estimate. This approach used an analysis similar to the program evaluation and review technique (PERT), which is more commonly used in project scheduling, to assign certainty factors to cost estimates. The approach uses a combination of historical bid data for major roadway items whose quantities can be estimated early in the development process and historical percentages for other major components of the project, called allowance and contingency factors. The paper focuses on (1)the methodology developed to analyze the historical bid data; (2)the analysis of 14 highway corridors with 77 projects whose as-bid construction costs were more than $830million; and (3)a cross-validation of the approach used to validate the accuracy of the predictive model. By using a PERT-type technique, construction costs were accurately predicted at the conceptual stage within 20%. However, approximately 85% of the corridor costs were accurately predicted within 15% of the actual cost. The proposed methodology provides a structured and consistent estimating approach that can be used by any SHA that needs to develop total project delivery estimates at the conceptual design stage.

Original languageEnglish (US)
Pages (from-to)942-949
Number of pages8
JournalJournal of Construction Engineering and Management
Volume137
Issue number11
DOIs
StatePublished - Nov 2011
Externally publishedYes

Fingerprint

Costs
PERT
Conceptual design
Cost estimates
Scheduling
Bid
Construction costs
Methodology
Program evaluation
Contingency factors
Factors
Project delivery
Cross-validation
Development process
Project scheduling

Keywords

  • Conceptual design
  • Costs
  • Estimation
  • Highway and road construction
  • Statistics

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Strategy and Management
  • Industrial relations
  • Building and Construction

Cite this

New approach to developing conceptual cost estimates for highway projects. / El Asmar, Mounir; Hanna, Awad S.; Whited, Gary C.

In: Journal of Construction Engineering and Management, Vol. 137, No. 11, 11.2011, p. 942-949.

Research output: Contribution to journalArticle

@article{70de761b2f2246868b054d874f24ca61,
title = "New approach to developing conceptual cost estimates for highway projects",
abstract = "Developing a reliable project cost estimate is a challenge for any state highway agency (SHA), especially at the conceptual stage. A conceptual estimate is defined in this paper as the estimate prepared at the point at which only 30{\%} of the design is complete. This paper describes a statistical approach to producing a reliable conceptual cost estimate when few project design details have been finalized and many assumptions still form the basis of the estimate. This approach used an analysis similar to the program evaluation and review technique (PERT), which is more commonly used in project scheduling, to assign certainty factors to cost estimates. The approach uses a combination of historical bid data for major roadway items whose quantities can be estimated early in the development process and historical percentages for other major components of the project, called allowance and contingency factors. The paper focuses on (1)the methodology developed to analyze the historical bid data; (2)the analysis of 14 highway corridors with 77 projects whose as-bid construction costs were more than $830million; and (3)a cross-validation of the approach used to validate the accuracy of the predictive model. By using a PERT-type technique, construction costs were accurately predicted at the conceptual stage within 20{\%}. However, approximately 85{\%} of the corridor costs were accurately predicted within 15{\%} of the actual cost. The proposed methodology provides a structured and consistent estimating approach that can be used by any SHA that needs to develop total project delivery estimates at the conceptual design stage.",
keywords = "Conceptual design, Costs, Estimation, Highway and road construction, Statistics",
author = "{El Asmar}, Mounir and Hanna, {Awad S.} and Whited, {Gary C.}",
year = "2011",
month = "11",
doi = "10.1061/(ASCE)CO.1943-7862.0000355",
language = "English (US)",
volume = "137",
pages = "942--949",
journal = "Journal of Construction Engineering and Management - ASCE",
issn = "0733-9364",
publisher = "American Society of Civil Engineers (ASCE)",
number = "11",

}

TY - JOUR

T1 - New approach to developing conceptual cost estimates for highway projects

AU - El Asmar, Mounir

AU - Hanna, Awad S.

AU - Whited, Gary C.

PY - 2011/11

Y1 - 2011/11

N2 - Developing a reliable project cost estimate is a challenge for any state highway agency (SHA), especially at the conceptual stage. A conceptual estimate is defined in this paper as the estimate prepared at the point at which only 30% of the design is complete. This paper describes a statistical approach to producing a reliable conceptual cost estimate when few project design details have been finalized and many assumptions still form the basis of the estimate. This approach used an analysis similar to the program evaluation and review technique (PERT), which is more commonly used in project scheduling, to assign certainty factors to cost estimates. The approach uses a combination of historical bid data for major roadway items whose quantities can be estimated early in the development process and historical percentages for other major components of the project, called allowance and contingency factors. The paper focuses on (1)the methodology developed to analyze the historical bid data; (2)the analysis of 14 highway corridors with 77 projects whose as-bid construction costs were more than $830million; and (3)a cross-validation of the approach used to validate the accuracy of the predictive model. By using a PERT-type technique, construction costs were accurately predicted at the conceptual stage within 20%. However, approximately 85% of the corridor costs were accurately predicted within 15% of the actual cost. The proposed methodology provides a structured and consistent estimating approach that can be used by any SHA that needs to develop total project delivery estimates at the conceptual design stage.

AB - Developing a reliable project cost estimate is a challenge for any state highway agency (SHA), especially at the conceptual stage. A conceptual estimate is defined in this paper as the estimate prepared at the point at which only 30% of the design is complete. This paper describes a statistical approach to producing a reliable conceptual cost estimate when few project design details have been finalized and many assumptions still form the basis of the estimate. This approach used an analysis similar to the program evaluation and review technique (PERT), which is more commonly used in project scheduling, to assign certainty factors to cost estimates. The approach uses a combination of historical bid data for major roadway items whose quantities can be estimated early in the development process and historical percentages for other major components of the project, called allowance and contingency factors. The paper focuses on (1)the methodology developed to analyze the historical bid data; (2)the analysis of 14 highway corridors with 77 projects whose as-bid construction costs were more than $830million; and (3)a cross-validation of the approach used to validate the accuracy of the predictive model. By using a PERT-type technique, construction costs were accurately predicted at the conceptual stage within 20%. However, approximately 85% of the corridor costs were accurately predicted within 15% of the actual cost. The proposed methodology provides a structured and consistent estimating approach that can be used by any SHA that needs to develop total project delivery estimates at the conceptual design stage.

KW - Conceptual design

KW - Costs

KW - Estimation

KW - Highway and road construction

KW - Statistics

UR - http://www.scopus.com/inward/record.url?scp=83755183657&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=83755183657&partnerID=8YFLogxK

U2 - 10.1061/(ASCE)CO.1943-7862.0000355

DO - 10.1061/(ASCE)CO.1943-7862.0000355

M3 - Article

VL - 137

SP - 942

EP - 949

JO - Journal of Construction Engineering and Management - ASCE

JF - Journal of Construction Engineering and Management - ASCE

SN - 0733-9364

IS - 11

ER -