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To maintain road systems in the USA, state departments of transportation (DOTs) generally use in-house workers or private contractors. Limited studies have calculated the cost savings of hiring private contractors; however, most of them have not calculated cost savings based on life-cycle costs (LCCs). The purpose of this paper is to determine whether the LCC of chip seal and stripping maintenance activities performed by in-house workers are cheaper than those performed by private contractors.

The paper collected the hard cost data of chip seal and stripping maintenance activities performed by state DOT in-house workers, as well as private contractors, from 2003 to 2016 from the Nevada DOT Maintenance and Asset Management division. Statistical tests were conducted to test the research hypothesis that the LCC of chip seal and stripping activities performed by in-house workers are significantly less than those performed by private contractors.

The study results showed that the cost per unit and LCC of chip seal and striping work performed by in-house workers were significantly less than those performed by private contractors in Nevada.

The study only collected data from Nevada DOT, so readers should use caution in generalizing the findings of this study. Additionally, factors affecting the cost of these maintenance activities for private contractors are significantly different compared to in-house contractors. Therefore, these differences may be some of the potential reasons for cost difference between these two methods.

The practical implications of this study are that state DOT engineers need to plan for outsourcing chip seal and stripping maintenance activities only to private contractors that are cost effective, based on life-cycle cost.

The LCC analysis framework developed in this study will help state DOT engineers to determine cost savings by using in-house workers for road maintenance works.

Change orders (COs) adversely affect the cost and schedule of projects, specifically during the construction phase. COs of 95 new public school building projects contracted by the Clark County School District (CCSD) of Nevada were analyzed to quantify the cost and schedule growth as well as to determine the effect of COs on cost and schedule growth. The paper aims to discuss these issues.

The data were collected from CCSD through questionnaire survey. Descriptive statistics and statistical tests were conducted to determine the effect of COs on cost and schedule growth.

It was found that the average amount of COs as well as cost and schedule overruns were 5.9, 3.0 and 7.4 percent, respectively. Statistical tests showed that the amount of COs had an adverse effect on schedule growth; schedule overruns in projects with less than 4 percent COs were significantly lower than projects with more than 4 percent COs. Cost overruns did not significantly differ in those two types of projects. The primary contribution of this study is that it provides the tools and the framework for school district engineers to determine the probability of the occurrence of COs as well as the optimum percentage of COs for a minimum effect on cost and schedule growth of new public school buildings. Probability curves were also developed to determine the likelihood of the occurrence of COs, cost growth and schedule growth in these projects. These findings could be used by school districts to avoid or reduce COs in future projects, minimizing the effect on cost and schedule growth during the construction phase.

The findings and the probabilities curves developed in this study should be used carefully in other cases. These data were specific to the owner, location and types of buildings and generalizing these findings may have negative consequences.

The practical implications are that this study could provide a tool to school building administrators to determine the probability of having COs as well as cost and schedule overruns and the effects of COs on cost and schedule overruns. To the authors’ best knowledge, no other studies of this type have been conducted previously.

The social implication of this study is it will help to efficiently use the tax payers’ money while building new school buildings.

This study has collected the hard data of COs, cost and schedule data of CCSD new school building projects. Therefore, the data are from the projects completed by CCSD. So, the paper is written from the original data received from CCSD.

The purpose of this study is to determine the barriers and constraints executive decision-makers have to face during the delivery method selection stage of water and wastewater projects using alternative project delivery (APD) methods, e.g. design-build (DB), design-build-operate (DBO) and construction management-at-risk (CMAR).

Structured interviews were conducted with 18 executive decision-makers from public agencies to identify the reasons for transitioning to APD from the design-bid-build (DBB) method. Respondents were also asked about the major obstacles they faced during the decision-making process, as well as key positive and negative factors in using APD methods. The executive decision-makers were also asked about their lessons learned during this process. In addition, this study collected key steps in making APD water and wastewater projects successful. All of the findings from the interview phase were validated by seven public agency executive decision-makers of water and wastewater industries.

One major study finding was that executive decision-makers chose the APD method because it provided cost and schedule benefits and the owner could also choose the designer or builder based on qualifications. The study also found that the main obstacles executive decision-makers faced were: (1) difficulty in implementing APD methods because they do not follow the low-bid process, (2) reluctance to use DB/CMAR because of the status quo and (3) unfamiliarity of city councils/elected commissions with the DB/CMAR process. The validation survey found that most findings from the initial phase of interviews were confirmed by the executives who took part in validation phase.

The major limitation of this research is the small sample size. As the executive decision-makers are very hard to reach for interviews, the authors failed to get interviews from a large number of them, despite repeated efforts made by the authors. Another limitation of this study is that the authors contacted most of the executive decision-makers listed in the WDBC list. These executive decision-makers worked for public agencies and, therefore, the views from private agencies could not be included in this research. The authors understand that the validation of the study findings is very important. However, due to the scope and limited time available for the research, the authors could not validate the findings of this study with other public agencies.

Selecting APD methods instead of DBB methods in water and wastewater projects for public agencies is a crucial issue during the project planning phase. Agencies' executive decision-makers need to understand the advantages and disadvantages of APD methods, along with the transition process in order to smoothly deliver projects. The findings of this study will assist public agency executive decision-makers to mitigate risks, overcome obstacles and become more educated about the APD method process, so that these projects can be successfully delivered within budget and on time.

This paper contributes to the existing body of knowledge by identifying lessons learned related to various APD method issues, which can be utilized by municipal executive decision-makers to successfully complete future APD projects.

The purpose of this study is to determine whether there is a correlation between mobilization costs and project schedule performance of highway projects. In addition to this, the study will also determine if the mobilization costs are helping small or large highway projects in terms of improving the schedule performance.

The data of 206 highway projects were collected from the Department of Transportation of two states with the help of questionnaire survey. The cost, schedule and mobilization costs data were collected. The performance metrics related to construction schedule growth and construction intensity were developed in order to test the research hypotheses: mobilization costs will increase the schedule performance of highway projects. The data were also divided into two groups based on project cost and analyzed to check whether the mobilization costs impact the schedule performance of these highway projects. Spearman's correlation test was conducted to determine the correlation between dependent and independent variables. In addition, a Mann–Whitney test was conducted to determine the difference in medians of construction schedule growth and the construction intensity of these two groups of projects.

One major study finding was that there was no strong linear correlation between the mobilization cost percentage and the construction schedule growth and construction intensity of highway projects. However, the study found the projects that have 9% or more mobilization costs had significantly better schedule growth compared to the projects that have less than 9% mobilization costs. When data were analyzed based on the project size, it was found that this pattern was seen only in large projects costing equal to or more than $5 million.

This study's findings have very crucial practical implications to state DOTs contract engineers. This study shows that the highway contract engineers need to provide the right amount of mobilization costs to complete their projects on and before schedule. If the correct amount of mobilization costs is not provided to the contractors, the impact of these mobilization costs on reducing the schedule growth will be negligible. The findings of this study will assist public agency decision makers to complete their projects on or before time by including the mobilization costs provision in the contract. The state DOTs can improve their schedule performance by providing enough financial help to the contractors so that they can improve their cash flows and complete projects successfully within the given timeframe.

This paper contributes to the existing body of knowledge by validating the impact of mobilization costs on the schedule performance of highway projects. There has been no empirical study conducted prior to this to identify the role of mobilization costs on reducing the schedule growth of highway projects.