Plenty of studies on exclusive lanes for Connected and Autonomous Vehicle (CAV) have been conducted recently about traffic efficiency and safety. However, most of the previous research studies neglected comprehensive consideration of the safety impact on different market penetration rates (MPRs) of CAVs, traffic demands, and proportion of trucks in mixture CAVs with human’s driven vehicle environment. On this basis, this study is to (1) identify the safety impact on exclusive lanes for CAVs under different MPRs with different traffic demands and (2) investigate the safety impact of trucks for CAV exclusive lanes on mixture environment. Based on the Intelligent Driver Model (IDM), a CAV platooning control algorithm is proposed for modeling the driving behaviors of CAVs. A calibrated 7-kilometer freeway section microscopic simulation environment is built by VISSIM. Four surrogate safety measures, including both longitudinal and lateral safety risk indexes, are employed to evaluate the overall safety impacts of setting exclusive lanes. Main results indicate that (1) setting one exclusive lane is capable to improve overall safety environment in low demand, and two exclusive lanes are more suitable for high-demand scenario; (2) existence of trucks worsens overall longitudinal safety environment, and improper setting of exclusive lanes in high trucks, low MPR scenario has adverse effect on longitudinal safety; and (3) setting exclusive lanes have better longitudinal and lateral safety improvement in high-truck proportion scenarios. Setting one or two exclusive lanes led to [+42.4% to −52.90%] and [+45.7% to −55.2%] of longitudinal risks while [−1.8% to −87.1%] and [−2.1% to −85.3%] of lateral conflicts compared with the base scenario, respectively. Results of this study provide useful insight for the setting of exclusive lanes for CAVs in a mixture environment.

Mechanical instabilities in soft materials have led to the formation of unique surface patterns such as wrinkles and cracks for a wide range of applications that are related to surface morphologies and their dynamic tuning. Here, we report a simple yet effective strategy to fabricate strain-tunable crack and wrinkle microvalves with dimensions responding to the applied tensile strain. The crack microvalves initially closed before stretching are opened as the tensile strain is applied, whereas the wrinkle microvalves exhibit the opposite trend. Next, the performance of crack and wrinkle microvalves is characterized. The design predictions on the bursting pressure of microvalves and others from the theory agree reasonably well with the experimental measurements. The microfluidic devices with strain-tunable crack and wrinkle microvalves have then been demonstrated for microsphere screening and programmable microfluidic logic devices. The demonstrated microfluidic devices complement the prior studies to open up opportunities in microparticle/cell manipulations, fluidic operations, and biomedicine.

Design of microfluidic reservoir with improved performance is essential in flexible epidermal microfluidic devices, which often suffer from structural instability due to the low stiffness and strong adhesion of the reservoir made of soft elastomers, causing the so‐called self‐collapse phenomena. Here, a method is proposed to fabricate a flexible superhydrophobic poly(dimethylsiloxane) (PDMS) layer with a low‐adhesive surface for epidermal microfluidic device by using chemical etching and soft lithography techniques. The obtained PDMS layer exhibits ultralow dry adhesion with great stability compared to previously made soft layer often having relatively high adhesion. Remarkably, this layer is able to maintain its ultralow adhesion with various counterpart engineering materials even in different environmental conditions, including dry, under water, and under oil conditions, and it exhibits an excellent time durability (more than one month) and use‐stability (at least 20 cycles). It is later shown that the designed PDMS layer with ultralow‐adhesive and superhydrophobic surface can be applied to prevent the self‐collapse of roof effectively in microfluidic reservoir. This study provides an effective design strategy to develop flexible elastomeric materials with controllable adhesion, paving the way for improving the mechanical and structural stability of large dimension reservoirs in wearable microfluidics through surface engineering.

No abstract

No abstract