1. Background
Many of the rural areas in the United States struggle to retain a sufficient range of facilities ensuring necessary services to the local population. These difficulties are exacerbated in areas experiencing population decline [
1,
2]. Existing literature provides multiple definitions for rural areas [
3,
4,
5]. The United States Census defines a rural area based on its population density; accordingly, a rural area is defined as an area with a population of less than 1000 persons per square mile [
5]. In 2001, the Federal Highway Administration (FHWA) defined a rural area as an area with a population of less than 5000 and/or the outside area of a metropolitan area with a population of less than 50,000 people [
4]. In the present study, the research team adopted the FHWA 2001 definition.
Rural transportation plays a critical role globally in the socio and economic conditions of rural communities [
6], as it provides them with access to education, work, and health services [
7]. Rural mobility has been recently challenged by an increased demand that is due to an aging population and inadequate resources [
8], as transit projects in rural areas commonly receive less attention and fewer resources than projects in urban areas [
9] and have to compete with them for funding [
10]. To develop rural mobility, governments need to invest in constructing various type of facilities, such as remote roads, transit stops, and park-and-ride lots, and minimize the amount and number of cost overruns, which are related to unreliable and inaccurate cost estimations [
11,
12].
Tran et al. [
3] explained that cost overruns in rural transit facilities commonly occur because the scope of the projects is limited, the funding is constrained, and the locations are spread geographically. Accurate and reliable cost estimation is never easy to achieve because of the many uncertainties that are inherent in the construction process. Multiple researchers and practitioners [
13,
14,
15,
16] espoused that decision-makers and estimators must make correct and reasonable assumptions to minimize the consequences of these uncertainties, based on: (1) thorough information pertaining to the project’s nature, (2) a traditional cost database, and (3) an acceptable estimation method or tool.
Some researchers and practitioners have indicated that there is a dearth of comprehensive information and documented data related to rural transit facility projects [
7,
10,
17,
18]. Hallowell et al. [
17] indicated that many Department of Transportation (DOT) representatives, city/county managers, and transit officials are silent on construction management practices of rural transportation facility projects, and without their input and the benefit of sufficient data and information in existing literature on the characteristics of rural transit facilities and on viable current cost estimating practices, it is difficult to provide reliable and accurate cost estimates during the early stages of the projects [
19].
The growth of rural transportation facilities plays a crucial role in the economic, social, and political health of modern society. The development of rural infrastructures, such as remote roads, bridges, and transit stops, improves the important transportation linkages between rural and urban areas and is necessary for improving the quality of life and maintaining economic stability in rural areas [
3,
20,
21]. Multiple sectors, such as the agricultural sector, depend on transportation, particularly on roads [
22,
23]. The advantages and benefits of expanding regional transit facilities are recorded in the Regional Transit Coordination Guidebook [
24], which espouses that the benefits are important for transit riders, transit travelers, transit providers, transportation systems, and the workforce.
The US DOT established the Rural Transportation Program in 1999 to improve the capacity of rural transit facility projects in the US. This program had several targets: (1) enhance the quality of life in rural areas, (2) increase the safety of the transportation system, (3) decrease material costs of transportation systems, (4) protect the rural natural environment, (5) enhance potential trade, (6) enhance the economic condition of rural areas, and (7) provide national security and border integrity.
In 2012, the Texas Department of Transportation (TXDOT) [
25] classified transit facilities into three main categories and eight subcategories, as shown in
Figure 1. The three main categories of transit facilities are operations and maintenance, large passenger, and small passenger. These classifications reflect the nature and characteristics of rural transit facilities and are beneficial for further analyses and efficient management [
26].
The American Public Transportation Association recommended useful practices for implementing a new bus transit facility project and maintenance services in 2010 [
27]. The activities associated with the facility services and maintenance were categorized into three classes and levels (Level I, Level II, and Level III), as presented in
Figure 2. Their classification leads to higher performance, efficient funding allocation, and effective management of rural transit facilities [
28,
29,
30].
Rural transit facility projects are commonly small in scope, but numerous and geographically dispersed, so these projects account for a significant portion of funds expended on transportation projects in the U.S. [
3]. Accurate cost estimation of these projects leads to considerably fewer transportation cost overruns. [
11] stated that transit agencies require reliable cost estimates for the following reasons: (1) reliable estimated costs of transit facilities in the form of simple averages or cost functions during the planning phase [
31,
32,
33], assist in establishing the funding commitments, and prevent the likelihood and magnitude of cost overruns [
12]; (2) cost performance is the key factor in assessing the overall cost-effectiveness of transit facility projects [
34]; and (3) accurate cost estimation and prediction help transit agencies appropriately allocate and prioritize resources in situations where the demand for transit outstrips the available funding. For the stated reasons and for purposes of effective management of transit systems in general, agencies seek to continually develop and update planning-level cost models [
11].
Multiple researchers and practitioners believe that the challenges associated with estimating costs for rural transit facilities include a lack of documented cost data, remote locations, and less competition [
3,
35,
36]. To address those challenges, [
3] recommended various resources and methods, such as providing pricing directories and precise cycle time charts for machinery, supplies, and manpower.
Anderson et al. [
37] introduced some issues regarding rural and small transit facility projects: the inability to complete rural and small transit facility projects due to lack of funding, and the prevalent use of consultants for estimating the cost of the projects. Virtually all of the DOTs hire consultants for cost estimations of these projects, and then hire additional consultants to review the accuracy of the estimates.
Zheng [
38] identified the reasons that it is difficult to accurately estimate the costs of rural transit facility projects: (1) lack of an organized procedure for cost estimating through the planning, programming, and project development phases; (2) possibility of renovation of the rural transit facilities; (3) a wide range of functions in these projects; (4) the wide size of transit facility projects; and (5) unique challenges associated with transit facility projects.
3. Research Framework
In this step, a conceptual framework was provided to illustrate the objective of each step of the research process and to show how the objectives relate to one another. The conceptual research framework, presented in
Figure 3, began with a thorough review of transit agencies’ related documents and transportation agencies’ websites, such as the Metropolitan Transportation Commission’s online library. These resources include important details on common types and sizes of rural transit facilities, site factors, and statistical data on the design and building costs. Following a review of the literature, characteristics of rural transportation facilities were described, as well as the scope of the state of practice was identified.
As aspects of rural transit facilities were required that were not addressed in existing literature, multiple interviews were conducted to help the research team develop a structured survey. Telephone interviews are commonly considered an additional source and useful method for procuring information for reviewing and assessing rural transit facilities (NCHRP 20-65 Task 53) [
36], and were utilized in this research. An interview protocol was developed, based on the information that the research team obtained through review of the related documents from the transit agencies. It consisted of 13 in-depth questions belonging to the categories of general information, project size, project cost, project duration, historical cost data, risk factors, contingency estimation, and critical items.
A structured survey was then developed to collect comprehensive information and data regarding the various aspects of rural and small transit facilities. As shown in
Figure 3, the survey protocol consisted of questions related to the project memorandum, survey instructions, survey declarations, respondent information, characteristics of the project, cost estimating, project schedules, project risks, change orders, and others. The research team distributed the survey to more than 1600 personnel working in 52 DOT agencies that were involved in rural small transit projects, and sent them two follow-up emails. They then called the DOTs to ask them to complete the survey, but were told that the DOT agencies did not have any historical or documented data or information pertaining to rural and small transit facility projects.
Next, the research team expanded their efforts by locating private firms nationwide who conducted construction projects in rural communities and sending the survey to them. After sending two follow-up emails, they received a few responses to the effect that they could not share the information and data due to confidentiality mandates.
Finally, the research team contacted the National Rural Transit Assistance Program (National RTAP) regarding the low response rate, and the executive director published an announcement in their newsletter. After all of the mentioned efforts, only 26 completed surveys were collected.
Then, descriptive data analyses were performed for the design and construction phases to describe the basic features of the data in this study. To provide useful information and data for different project parties, such as owners and contractors, different aspects of rural transit facility projects were assessed and analyzed. The contract types were reviewed and the implemented cost estimating methods were assessed and analyzed. Additionally, cost breakdowns corresponding to each construction system of rural transportation facilities were studied. Finally, the regression analysis technique was used to develop a predictive modeling technique for cost estimates. Two regression models were generated to examine the relationship between the design costs/construction costs and project size.
3.1. Interview
The research team made concerted efforts to develop an interview protocol that considered critical questions, for which there were few, if any, literature resources. The protocol consisted of 13 questions, classified into eight categories: general information, project size, project cost, project duration, historical cost data, risk factors, contingency estimation, and critical items. These could be covered in a one-hour interview.
The interview protocol and project memorandum were sent to 13 professional consultants and DOT employees (five DOT employees, six transit managers, and two consultants) who were actively involved in transit management teams, had more than ten years of experience in rural and small urban transit facility projects, and were located in different regions of the United States. The project memorandum presented information pertaining to the background of this study, such as objectives, procedures, and time and date of the interview. The purpose of the interview was explained in the research background, and the characteristics of the rural transit facility projects were explained in the expectations and instructions. The interviewees were expected to review the interview protocol and project memorandum so that they could be prepared for the interview questions. Of the 13 invited to participate, only six were willing to be interviewed: three DOT personnel, two consultants, and one transit manager. Multiple articles and books have suggested that anywhere from 5 to 50 participants as adequate for conducting in-depth interviews [
40].
3.2. Survey
After conducting the phone interviews, the research team utilized the results of interviews and developed a survey that was designed to gather historic project-specific cost estimates from the consulting firms, state DOTs, and transit agencies associated with transit facilities: (1) types and sizes of facilities, (2) features of facilities, (3) locations of facilities, (4) actual design costs, (5) actual construction costs, (6) design schedules, (7) construction schedules, (8) unexpected conditions, and (9) cost of construction components. Brief descriptions of the 11 survey sections are presented in
Table 1.
Before distributing the survey, a pilot survey was conducted by sending the questionnaire to four practitioners who were managers of rural transit facility projects and were introduced to the research team by a member of the RTAP. The research team asked the practitioners to complete the survey in order to ensure: (1) the efficacy of the questionnaire; (2) the clarity of the survey instructions; (3) the efficiency of the survey’s format; and (4) the prevention of any errors in the survey. The feedback was used to revise the survey questions.
Next, the research team sent the survey to the personnel of 52 state DOTs and consulting firms who were program managers, transit managers, or consultants of rural transit facilities. The survey was conducted online, and the survey invitations were sent through email. Follow-up survey requests were sent to the same group of people. Despite two follow-up emails, only 26 surveys, belonging to 26 different state DOTs, were returned because of the respondents’ difficulty in accessing actual project data.
6. Conclusions
As there is insufficient information and data associated with rural transit facilities, the ultimate aim of this study was to provide a baseline estimates for both design and construction costs of rural transit projects. In addition, this study identified the key components of rural transit facilities, identified design and construction cost estimating methods, determined construction risk factors, assessed the cost of each construction system, and identified design and construction contract types associated with rural transit facilities.
Two regression models were developed to predict the design and construction costs. It was concluded that size is a significant predictor in determining the conceptual design and construction costs of rural transit facilities. Moreover, the results demonstrated that the “similar projects’ cost technique” was the most frequently used method in which the actual cost of previous similar projects are utilized for estimating the cost of the present project. The lump sum contract was employed most often for both the design and construction phases. In this contract type, the contractor agrees to complete the project for a fixed price. The data collected from interviews were used to identify risk factors, and their frequencies were determined using an online survey. The most frequently encountered construction risk factors were soil conditions and unexpected underground conditions. To manage project risks, contingency is projected as a percentage of construction cost. The contingency percentage ranges provided by interview respondents and survey results served as a guide for establishing the default contingency range for the cost estimating prototype tool. Lastly, a straight-line regression model was generated to estimate both the design and construction costs based on the project size of the rural transit facilities. The findings of this study provide a beneficial baseline estimate for the design and construction costs in the early stages of the rural transit facility projects, and will assist DOTs in accurately analyzing bidders’ proposed cost estimates, enabling them to select the one that most effectively minimizes the potential for cost overruns.
Although this research was exploratory in nature and somewhat limited by the relatively small number of interviews and completed surveys, the authors made every effort to provide valid and reliable outcomes. It is, however, recommended that future studies query a larger number of DOT representatives to obtain more comprehensive results. The models were not generated as a replacement for estimates of design and construction costs associated with rural transit facilities, which require detailed construction cost techniques. In addition, this study relied on information pertaining to U.S. rural transit facility projects and lacks cross-professional, cross-organizational, and cross-national studies from rural transit facility projects worldwide.