Thermal state of ice-rich soils on the Tommot-Yakutsk Railroad right-of-way

This paper summarizes the results of investigations carried out in the northern section of the Tommot-Yakutsk Railroad in eastern Siberia, underlain by ice-rich permafrost. The ongoing permafrost and geotechnical research program in support of railroad construction includes assessment of the ground thermal state on the right-of-way and adjacent areas based on long-term field observations using the method of terrain thermal physics. These studies focus on the upper permafrost within the depth of annual temperature variation. In undisturbed areas, inter-annual variability of the ground thermal state shows little response to recent climatic variations. However, forest clearing and surface disturbance during right-of-way construction cause an increase in permafrost temperature, deepening of the active layer, thaw settlement, and water accumulation along the embankment. The active layer is thickest along the sun-exposed left berm and is thinnest along the more shaded right berm. Measures to prevent thaw-related embankment problems are recommended.

Research on Travel Preferences of Wheelchair Users in Barrier-Free Environments and Improvement Strategies for Adaptive Urban Roads

The construction of a barrier-free environment is an important measure that guarantees the safety,right-of-way,and interests of the disabled,the elderly,and other mobility disadvantaged groups.It is also an indispensable part of the low-carbon urban transportation and a necessary way to protect the rights of mobility disadvantaged groups in green travel.In this paper,the researchers conducted life log surveys on the travels of 10 wheelchair users residing in Beijing with IoT Inspector,a self-developed,wheelchairmountable intelligent sensing device.Wheelchair users’travel preferences and reasons were then analyzed using the image and textual data from the surveys.Combined with a mapping workshop,a comparative analysis was performed on the bumpiness of sidewalk paving materials.The study found that wheelchair travelers’preferred non-motor lanes over sidewalks;substandard curb ramps,unleveled tree pools,limited access widths,and bumpy pavement were the main problems faced by wheelchair users in sidewalk accessibility.In addition,the study explores the inclusive needs and challenges of non-motorized right-of-way for new transportation means at urban planning and traffic management levels.Based on multi-sourced data,this paper discusses the possibility of assessing urban barrier-free environment and representing a narrative of the needs of mobility disadvantaged groups,so as to provide practical experience and technical support to the improvement strategies of adaptive roads.

Tunnel bottleneck management with high-occupancy vehicle priority on intelligent freeways

Tunnels on freeways,as one of the critical bottlenecks,frequently cause severe congestion and passenger delay.To solve the tunnel bottleneck problem,most of the existing research can be divided into two types.One is to adopt variable speed limits(VSLs)to regulate a predetermined speed for vehicles to get through a bottleneck smoothly.The other is to adopt high-occupancy vehicle(HOV)lane management.In HOV lane management strategies,all traffic is divided into HOVs and low-occupancy vehicles(LOVs).HOVs are vehicles with a driver and one or more passengers.LOVs are vehicles with only a driver.This kind of research can grant priority to HOVs by providing a dedicated HOV lane.However,the existing research cannot both mitigate congestion and maximize passenger-oriented benefits.To address the research gap,this paper leverages connected and automated vehicle(CAV)technologies on intelligent freeways and develops a tunnel bottleneck management strategy with a dynamic HOV lane(DHL).The strategy bears the following features:1)enables tunnel bottleneck management at a microscopic level;2)maximizes passenger-oriented benefits;3)grants priority to HOVs even when the HOV lane is open to LOVs;4)allocates right-of-way segments for HOVs and LOVs in real time;and 5)performs well in a mixed-traffic environment.The proposed strategy is evaluated through comparison against the non-control baseline and a VSL strategy.Sensitivity analysis is conducted under different congestion levels and penetration rates.The results demonstrate that the proposed strategy outperforms in terms of passenger-oriented delay reduction and HOVs’priority level improvement.