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Many investors have less interest in tendering for public-private partnership (PPP) construction projects as a result of the uncertain risks associated with the project delivery. Moreover, PPP project stakeholders have inadequate information about the probable impacts of time-based delay imposed on PPP projects under the PPP arrangement. This study aims to identify and categorize construction stakeholders’ perceptions of the impact of time-based delays on PPP construction projects.

A purposive sampling technique was adopted where questionnaires were used as the primary instrument for gathering data from PPP experts. Cronbach’s alpha coefficient and Kendall’s concordance were used to measure the reliability of the scale and the respondent’s level of agreement, respectively. One sample t-test, mean score ranking and principal component analysis were used to analyse the identified time-based delay impacts.

The study revealed seven significant impacts of time-based delay on PPP construction project delivery as: “project schedule overrun”, “idling of project resources”, “project cost overrun”, “poor quality of completed works”, “delayed realization of project benefits”, “frequent arbitration/litigation in PPP projects” and “total abandonment of PPP projects”. The study further identified the top five significant impacts of time-based delay on PPP project stakeholders as: “reduction in motivation to attract investment”, “high interest on finance (loans)”, “contractor in financial crisis”, “loss of public confidence in government” and “reduction in parties’ reputation”.

The identified significant impacts of time-based delays will increase stakeholders’ awareness of the repercussions and effects that time-based delays may impose on PPP construction projects if not appropriately managed throughout the project implementation. This awareness will further guide stakeholders to implement targeted risk management strategies to minimize the negative consequences of delays on PPP project performance.

As a pioneering study that provides a better understanding of the impacts of time-based delays on PPP construction projects, this study enhances knowledge of PPP construction project implementation.

Autonomous vehicles (AVs) have the potential to transform the infrastructure, mobility and social well-being paradigms in New Zealand (NZ) amid its unprecedented population and road safety challenges. But, public acceptance, co-evolution of regulations and AV technology based on interpersonal and institutional trust perspectives pose significant challenges. Previous theories and models need to be more comprehensive to address trust influencing autonomous driving (AD) factors in natural settings. Therefore, this study aims to find key AD factors corresponding to the chain of human-machine interaction (HMI) events happening in real time and formulate a guiding framework for the successful deployment of AVs in NZ.

This study utilized a comprehensive literature review complemented by an AV users’ study with 15 participants. AV driving sprints were conducted on low, medium and high-density roads in Auckland, followed by 15 ideation workshops to gather data about the users’ observations, feelings and attitudes towards the AVs during HMI.

This research study determined nine essential trust-influencing AD determinants in HMI and legal readiness domains. These AD determinants were analyzed, corresponding to eight AV events in three phases. Subsequently, a guiding framework was developed based on these factors, i.e. human-machine interaction autonomous driving events relationship identification framework (HMI-ADERIF) for the deployment of AVs in New Zealand.

This study was conducted only in specific Auckland areas.

This study is significant for advanced design research and provides valuable insights, guidelines and deployment pathways for designers, practitioners and regulators when developing HMI Systems for AD vehicles.

This study is the first-ever AV user study in New Zealand in live traffic conditions. This user study also claimed its novelty due to AV trials in congested and fast-moving traffic on the four-lane motorway in New Zealand. Previously, none of the studies conducted AV user study on SUV BMW vehicle and motorway in real-time traffic conditions; all operations were completely autonomous without any input from the driver. Thus, it explored the essential autonomous driving (AD) trust influencing variables in human factors and legal readiness domains. This research is also unique in identifying critical AD determinants that affect the user trust, acceptance and adoption of AVs in New Zealand by bridging the socio-technical gap with futuristic research insights.