This meta-analysis has examined the past ten years’ studies concerning the causes of construction project delay. It aims to update the subject area and investigate critical causes of project delay in three different conditions of the external environment. The data from 50 studies have been analyzed and synthesized to determine the top ten critical causes of delay. The Relative Importance Index (RII) technique was applied to rank the critical causes; subsequently, the Spearman’s rank correlation coefficient was calculated to evaluate the critical causes. The review findings indicate substantial differences between the critical causes of project delay in defined situations. The top ten critical causes of delay in developed countries root in the project’s internal environment. The leading causes of delays in developing countries are from the project’s internal and task environment. While in countries with various constraints and high risk, the general environment has a critical impact alongside the project task and internal environment on time overrun of a project. Moreover, this review summarized and categorized the best available studies to propose a systematic approach in identifying critical causes of delay to bridge the existing knowledge gap.

Unmanned aircraft systems (UAS) are an excellent tool to remove bridge inspection workers from potential harm. Previous research has documented that UAS for bridge inspection is a strategic priority of a state’s Department of Transportation (DOT), and this paper presents how they can increase safety and presents one methodology to quantify the economic benefit. Although previous studies have documented the potential benefits of using UAS for bridge inspection, these studies have primarily focused on efficiency and capabilities. This paper investigates in greater detail the potential to use UAS to increase the safety of bridge inspection, and includes the results of a survey of bridge inspectors, as well as a benefit cost methodology that utilizes worker compensation rates to quantify the safety benefits of UAS; the methodology is demonstrated using a case study for a DOT. The results of this research present evidence that UAS can increase the safety of bridge inspection, and the benefit–cost methodology and analysis suggest that using UAS to increase safety will provide benefits that are greater than agency costs.

This paper documents a case study of an automated mower to support sustainability at an airport. Mowing is an essential component of an airport’s Wildlife Hazard Management Plan (WHMP), which reduces the risk of birds and other wildlife to aircraft operations. Many airports have large areas of land (hundreds or even thousands of acres), which requires significant resources to manage and mow; experience at the Purdue Airport (KLAF) suggests that automated mowing may support economic and environmental aspects of sustainability. Automated mowing supports economic efficiency by reducing personnel requirements, although personnel are still needed for inspections, maintenance, and “mower rescue” if there is a malfunction (technical or field issue). Automated mowing supports environmental impacts by reducing local emissions since the mower is powered by electricity rather than gasoline; this benefit would be increased with the use of solar-powered mowers. Automated mowing may not be viable everywhere, and factors such as terrain, access to available power, acreage, and location on the airfield (including proximity to protected areas) must be carefully considered. Although automated mowing will not completely replace traditional mowing in the near future, autonomous mowers in remote areas may be an appropriate practice to support airport sustainability.

The importance of knowledge management (KM) in the Architecture, Engineering, and Construction (AEC) industry has risen with the improvement of information and communication technologies. However, the construction industry still struggles to capture and disseminate lessons learned. The present research explores this issue by using interviews and an online questionnaire, to provide updated information on lesson-learned procedures and their challenges in United States (US) construction companies. To do this, the authors have gathered industry professionals’ perceptions about lessons learned and methods used in their companies for harnessing and disseminating the knowledge generated by them. Our findings indicate that post-project evaluations are frequently conducted, utilize a two-step approach (review of materials followed by meetings), and are mainly organized by project managers. Most often, only key project team members are present in meetings to create a safe environment for discussion. Moreover, our findings echo previous research on the dissemination and reuse of lessons learned, indicating that these procedures are scattered and, most of the time, the information is not effectively reutilized. This suggests that US construction companies still need to revisit how information from lessons learned is currently being harnessed, stored, and especially shared (within and between companies) so that information can be effectively transformed into knowledge that can advance the AEC industry's productivity.