This paper develops a semi-nonparametric Poisson regression model to analyze motor vehicle crash frequency data collected from rural multilane highway segments in California, US. Motor vehicle crash frequency on rural highway is a topic of interest in the area of transportation safety due to higher driving speeds and the resultant severity level. Unlike the traditional Negative Binomial (NB) model, the semi-nonparametric Poisson regression model can accommodate an unobserved heterogeneity following a highly flexible semi-nonparametric (SNP) distribution. Simulation experiments are conducted to demonstrate that the SNP distribution can well mimic a large family of distributions, including normal distributions, log-gamma distributions, bimodal and trimodal distributions. Empirical estimation results show that such flexibility offered by the SNP distribution can greatly improve model precision and the overall goodness-of-fit. The semi-nonparametric distribution can provide a better understanding of crash data structure through its ability to capture potential multimodality in the distribution of unobserved heterogeneity. When estimated coefficients in empirical models are compared, SNP and NB models are found to have a substantially different coefficient for the dummy variable indicating the lane width. The SNP model with better statistical performance suggests that the NB model overestimates the effect of lane width on crash frequency reduction by 83.1%.

To understand drivers' perspectives and address barriers to the adoption of electric vehicles (EVs), this study primarily delves into two significant psychological aspects: range anxiety and willingness to pay (WTP) for charging among EV drivers. The Technology Acceptance Model and Expectation Confirmation Model are integrated to capture motivations that influence EV acceptance. Based on a sample of 677 Chinese EV users, the study reveals that user satisfaction and perceived ease of use play a critical role in mitigating range anxiety. Both external (satisfaction, perceived ease of use) and internal (range anxiety, charging habits, risk-averse attitude) motives are key determinants in increasing the WTP for charging. Among these, improvements in user satisfaction exert the most significant impact on reducing range anxiety and enhancing WTP for charging. Furthermore, the Multiple Indicators Multiple Causes model was employed to examine the effects of socioeconomic attributes on latent psychological factors. The findings highlight the importance of adopting customer-centered strategies in the formulation of policy interventions.

A semi-nonparametric generalized multinomial logit model, formulated using orthonormal Legendre polynomials to extend the standard Gumbel distribution, is presented in this paper. The resulting semi-nonparametric function can represent a probability density function for a large family of multimodal distributions. The model has a closed-form log-likelihood function that facilitates model estimation. The proposed method is applied to model commute mode choice among four alternatives (auto, transit, bicycle and walk) using travel behavior data from Argau, Switzerland. Comparisons between the multinomial logit model and the proposed semi-nonparametric model show that violations of the standard Gumbel distribution assumption lead to considerable inconsistency in parameter estimates and model inferences.

Objective: To analyze the mental health and erectile function status of men using sperm donor during pregnancy after ICSI failure in severe oligoasthenospermia and to provide reference for clinical implementation of more targeted psychological intervention and nursing for this group. Methods: A total of 410 sterile men who received assisted pregnancy treatment in our hospital from December 2020 to December 2022 and met the inclusion and exclusion criteria were collected as the study subjects. Among them, 68 patients with severe oligoasthenospermia who used donor assisted pregnancy after ICSI failure were used as the study group. Sixty-eight patients with severe oligoasthenospermia who continued to receive ICSI assisted pregnancy were matched by propensity score 1:1 as control group. General data questionnaire, self-rating Anxiety Scale (SAS), self-rating Depression Scale (SDS), Chinese version of perceived Stress Scale (CPSS) and International Erectile Function Index Rating Scale (IIEF-5) were used to conduct a cross-sectional investigation to compare the mental health and erectile function status of the two groups. Results: There were statistical differences in age and occupational status between the two groups before PSM (P < 0.05), but there was no statistical significance in social demographic data between the two groups after matching (P > 0.05). The incidence of anxiety, depression, stress and erectile dysfunction (ED) in the study group was higher than that in the control group, and there were statistical differences between the two groups (P < 0.05). Conclusion: The use of donor sperm to assist pregnancy has a great impact on the mental health and erectile function of infertile men. Medical personnel should pay attention to the mental health and erectile function of these men, and formulate targeted measures to help these patients actively cope with infertility, so as to improve the life and marriage quality of this group and improve their mental health status.