In the recent years,TNCs(transportation network companies)and on-demand ridesharing services have grown rapidly.Given conflicting reports on TNC impacts,a need exists to study mode choice shifts in the presence of TNC...In the recent years,TNCs(transportation network companies)and on-demand ridesharing services have grown rapidly.Given conflicting reports on TNC impacts,a need exists to study mode choice shifts in the presence of TNC services and their effects on urban congestion.Using Birmingham,AL(Alabama)as a case study,this paper showcases the feasibility of modeling TNC services using the MATSim(Multi-Agent Transport Simulation)platform,and evaluating the impact of such services on traffic operations.Data used for the study were gathered from Uber drivers and riders through surveys,as well as the US Census.The results indicate that when 200,400,and 800 TNC vehicles are added to the network,the VKT(vehicle kilometers traveled)increase by 22%,23.6%,and 23.2%,respectively,compared to the baseline scenario(no TNC service).Analysis of hourly average speeds,hourly average travel times,and hourly volumes along study corridors further indicate that TNC services increase traffic congestion,in particular,during the AM/PM peak periods.Moreover,the study shows that the optimal TNC fleet size for the Birmingham region is 400 to 500 active TNC vehicles per day.Such fleet size minimizes idle time and the number of TNC vehicles hovering,which have adverse impacts on TNC drivers,and the environment while ensuring TNC service availability and reasonable waiting times for TNC customers.展开更多
Over the last decade, the popularity of Transportation Network Companies (TNCs) as a mode of travel has been increasing at a steady pace. This trend <span style="font-family:Verdana;">highlights the im...Over the last decade, the popularity of Transportation Network Companies (TNCs) as a mode of travel has been increasing at a steady pace. This trend <span style="font-family:Verdana;">highlights the importance of identifying the determinants that influence transportati</span><span style="font-family:Verdana;">on users to adopt TNCs as a preferred mode choice and the impacts of su</span><span style="font-family:Verdana;">ch preferences on their travel patterns and transportation network o</span><span style="font-family:Verdana;">peration. This paper reports on a recent study undertaken in Birmingham, AL aiming at understanding and documenting the factors that influence transportation users to select TNCs (such as Uber/Lyft) for completing typical day trips. In </span><span style="font-family:Verdana;">doing so, a travel diary questionnaire survey was developed in accordance with</span> <span style="font-family:Verdana;">the Institute of Transportation Engineers (ITE) Manual on Transportation Engineering Studies using the Qualtrics Research Core platform. The que</span><span style="font-family:Verdana;">stionnair</span><span style="font-family:Verdana;">e was used to survey over 450 transportation users in the Birmingham Metro area. The survey participants provided detailed trip information for a </span><span style="font-family:Verdana;">typical 24-hr day along with demographic data and travel preference informatio</span><span style="font-family:Verdana;">n. The survey responses provide high-resolution micro-level indicators </span><span style="font-family:Verdana;">of travel preferences and behaviors in a TNC-served area, which is a much-needed </span><span style="font-family:Verdana;">type of information for researchers and transportation planning agencies.</span>展开更多
BACKGROUND With aging,four major facial retaining ligaments become elongated,leading to facial sagging and wrinkling.Even though synthetic fillers are popular,however,it cannot address the problems of soft tissue desc...BACKGROUND With aging,four major facial retaining ligaments become elongated,leading to facial sagging and wrinkling.Even though synthetic fillers are popular,however,it cannot address the problems of soft tissue descent alone,and injection of these fillers requires knowledge of the injection technique including the selection of injection sites,the amount of filler,and the dosage used per injection site.CASE SUMMARY This report aimed to assess the safety and efficacy of a nonsurgical retightening technique to lift and tighten the true ligaments of the face,to improve age-related skin sagging and wrinkling.We objectively quantified the aesthetic lifting effect of a nonsurgical facial retightening procedure that strategically injected high G’ fillers into the base of the true retaining ligaments of the face in two female patients.Facial images were recorded with a three-dimensional facial imaging system for comparison of the clinical outcome.The primary efficacy outcome was the change in facial anthropometric measurements obtained prior to and after injection.The patients were followed for 6 mo after the procedure.Skin retightening was observed,with an evident lift in the orbital,zygomatic,and mandibular regions,and the lifting effect was still observable at the 6-mo followup.Few mild adverse events,such as mild-to-moderate pain,tenderness,and itching,occurred during the 1 st week after the procedure.No adverse events were reported 1 mo post-procedure.CONCLUSION The results of this study demonstrated that our nonsurgical retightening procedure with strategically placed high G’ fillers achieved quantifiable aesthetic improvements in the orbital,zygomatic,and mandibular regions of two patients.Future research with a larger sample could provide a more in-depth evaluation and validation of the aesthetic improvements observed in this study.展开更多
基金the US DOT through the STRIDE University Transportation Center.
文摘In the recent years,TNCs(transportation network companies)and on-demand ridesharing services have grown rapidly.Given conflicting reports on TNC impacts,a need exists to study mode choice shifts in the presence of TNC services and their effects on urban congestion.Using Birmingham,AL(Alabama)as a case study,this paper showcases the feasibility of modeling TNC services using the MATSim(Multi-Agent Transport Simulation)platform,and evaluating the impact of such services on traffic operations.Data used for the study were gathered from Uber drivers and riders through surveys,as well as the US Census.The results indicate that when 200,400,and 800 TNC vehicles are added to the network,the VKT(vehicle kilometers traveled)increase by 22%,23.6%,and 23.2%,respectively,compared to the baseline scenario(no TNC service).Analysis of hourly average speeds,hourly average travel times,and hourly volumes along study corridors further indicate that TNC services increase traffic congestion,in particular,during the AM/PM peak periods.Moreover,the study shows that the optimal TNC fleet size for the Birmingham region is 400 to 500 active TNC vehicles per day.Such fleet size minimizes idle time and the number of TNC vehicles hovering,which have adverse impacts on TNC drivers,and the environment while ensuring TNC service availability and reasonable waiting times for TNC customers.
文摘Over the last decade, the popularity of Transportation Network Companies (TNCs) as a mode of travel has been increasing at a steady pace. This trend <span style="font-family:Verdana;">highlights the importance of identifying the determinants that influence transportati</span><span style="font-family:Verdana;">on users to adopt TNCs as a preferred mode choice and the impacts of su</span><span style="font-family:Verdana;">ch preferences on their travel patterns and transportation network o</span><span style="font-family:Verdana;">peration. This paper reports on a recent study undertaken in Birmingham, AL aiming at understanding and documenting the factors that influence transportation users to select TNCs (such as Uber/Lyft) for completing typical day trips. In </span><span style="font-family:Verdana;">doing so, a travel diary questionnaire survey was developed in accordance with</span> <span style="font-family:Verdana;">the Institute of Transportation Engineers (ITE) Manual on Transportation Engineering Studies using the Qualtrics Research Core platform. The que</span><span style="font-family:Verdana;">stionnair</span><span style="font-family:Verdana;">e was used to survey over 450 transportation users in the Birmingham Metro area. The survey participants provided detailed trip information for a </span><span style="font-family:Verdana;">typical 24-hr day along with demographic data and travel preference informatio</span><span style="font-family:Verdana;">n. The survey responses provide high-resolution micro-level indicators </span><span style="font-family:Verdana;">of travel preferences and behaviors in a TNC-served area, which is a much-needed </span><span style="font-family:Verdana;">type of information for researchers and transportation planning agencies.</span>
文摘BACKGROUND With aging,four major facial retaining ligaments become elongated,leading to facial sagging and wrinkling.Even though synthetic fillers are popular,however,it cannot address the problems of soft tissue descent alone,and injection of these fillers requires knowledge of the injection technique including the selection of injection sites,the amount of filler,and the dosage used per injection site.CASE SUMMARY This report aimed to assess the safety and efficacy of a nonsurgical retightening technique to lift and tighten the true ligaments of the face,to improve age-related skin sagging and wrinkling.We objectively quantified the aesthetic lifting effect of a nonsurgical facial retightening procedure that strategically injected high G’ fillers into the base of the true retaining ligaments of the face in two female patients.Facial images were recorded with a three-dimensional facial imaging system for comparison of the clinical outcome.The primary efficacy outcome was the change in facial anthropometric measurements obtained prior to and after injection.The patients were followed for 6 mo after the procedure.Skin retightening was observed,with an evident lift in the orbital,zygomatic,and mandibular regions,and the lifting effect was still observable at the 6-mo followup.Few mild adverse events,such as mild-to-moderate pain,tenderness,and itching,occurred during the 1 st week after the procedure.No adverse events were reported 1 mo post-procedure.CONCLUSION The results of this study demonstrated that our nonsurgical retightening procedure with strategically placed high G’ fillers achieved quantifiable aesthetic improvements in the orbital,zygomatic,and mandibular regions of two patients.Future research with a larger sample could provide a more in-depth evaluation and validation of the aesthetic improvements observed in this study.