Study on the Distribution of the Suburban Expressway Hourly Traffic Volume and Modification of the Design Hourly Volume under the Background of the Tourism Economy—Analysis on Design Factors of Normalized Congestion in Suburban Expressway

An unreasonable design hourly volume (DHV) greatly impacts road facility construction costs and traffic efficiency. With the rapid rise in the tourism economy and widespread emergence of holiday travel characteristics in China, DHV applicability for suburban expressways requires verification. This study collected annual traffic volume data over 8760 h along Xi’an Ring Expressway from 2017 to 2019. Traffic demand distribution patterns throughout the year and peak hours were analyzed on the basis of the descending order of the obtained hourly traffic volume (HV) and factor data. HV distribution characteristics, 30th highest hourly volume (30 HV) typicality, and DHV factor applicability were investigated. Due to travel characteristics under the background of the tourism economy, the peak HV distribution exhibits polarization characteristics. The recommended value of the design hour traffic factor in the specification corresponded to a number of hours greater than 200, with the 30 HV factor under the background of the tourism economy being 25% higher than the recommended value. Considering the tourism economy, the high level of traffic operation time increased significantly, and the characteristics of a sharp decline in the peak HV disappeared. The 30 HV factor no longer exhibited traditional characteristics. The design causes of traffic congestion are identified herein.

The Limited Responses of Provincial Expressway Network Operation Quality to the Impact of COVID-19: Taking Shaanxi Province as an Example

Recent research indicates that the coronavirus disease 2019 (COVID-19) pandemic has impacted road traffic operation quality. From the perspective of service level, safety level, and operation orderliness, this study attempts to analyze the limited responses of the operation quality of the provincial expressway network (PEN) to the impact of COVID-19. The traffic operation data of the PEN in Shaanxi Province were collected for three consecutive years (from 2019 to 2021) before and after the COVID-19 outbreak, including weekly average daily traffic, weekly traffic interruption times, weekly traffic control time, weekly traffic accidents, weekly traffic injuries, and weekly traffic deaths. Through descriptive statistics and dynamic analysis, we studied the limited responses of the safety and service levels of the PEN to the impact of COVID-19. An evaluation model of operation orderliness of the PEN was established by using dissipative structure theory and entropy theory. Results show that in 2020, the service level, safety level, and operation orderliness of the PEN dropped to their lowest. With the gradual control of pandemic, its negative impacts on the service level and operation orderliness of the PEN gradually decreased but did not recover to the pre-pandemic level. In terms of the safety level, the number of traffic accidents, traffic injuries, and traffic deaths decreased, whereas the traffic accident rate and accident casualty rate remained high. In summary, the operation quality of the PEN in Shaanxi Province has had a limited response to the impact of COVID-19.

CRISPR-Assisted DNA Detection, a novel dCas9-based DNA detection technique (preprint)

Nucleic acid detection techniques are always critical to diagnosis, especially in the background of the present COVID-19 pandemic. The simple and rapid detection techniques with high sensitivity and specificity are always urgently needed. However, the current nucleic acid detection techniques are still limited the traditional amplification and hybridization. To overcome the limitation, we here develop a CRISPR/Cas9-assisted DNA detection (CADD). In this detection, DNA sample is incubated with a pair of capture sgRNAs (sgRNAa and sgRNAb) specific to a target DNA, dCas9, a signal readout-related probe, and an oligo-coated solid support beads or microplate at room temperature for 15 min. During this incubation, the dCas9-sgRNA-DNA complex is formed and captured on solid support by the capture sequence of sgRNAa and the signal readout-related probe is captured by the capture sequence of sgRNAb. Finally the detection result is reported by a fluorescent or colorimetric signal readout. This detection was verified by detecting DNA of bacteria, cancer cell and virus. Especially, by designing a set of sgRNAs specific to 15 high-risk human papillomaviruses (HPVs), the HPV infection in 64 clinical cervical samples were successfully detected by the method. All detections can be finished in 30 minutes at room temperature. This detection holds promise for rapid on-the-spot detection or point-of-care testing (POCT).