published journal article
conference paper
published journal article
published journal article
published journal article
published journal article
Health risks, such as the probability of experiencing a side effect from a medication, are typically communicated numerically. However, presenting risks in strictly numeric formats is problematic considering that the public often experiences difficulty in comprehending strictly numeric probabilities. To help overcome this problem, Leonhardt and Keller (2018) tested the efficacy of using pictographs to visually present probabilistic information to health consumers. They found that the addition of pictographs alongside numeric probability information increased probability comprehension and lessened the perceived risk of a multiple risk health option. Here, we review relevant work on probability format and build on the general evaluability theory to posit why pictographs may result in lower risk perceptions of multiple risk options. We discuss current limitations in our understanding of how the public perceives multiple risk options, and we highlight opportunities for future research. For instance, we introduce Quick Response (QR) codes as a potential tool to help consumers view health risks in multiple formats on the Internet.
published journal article
published journal article
Microscopic simulation is used widely to analyze traffic networks. The outputs of such models, such as travel time and delay, depend in large part on the assumed parameter values. These parameters determine the traffic capacity, whose interpretation is not straightforward as the maximum discharge flow of a bottleneck in a freeway can be lower under congested conditions than in an uncongested situation. This phenomenon is often referred to as the capacity drop, and must be accurately portrayed by microsimulation models to simulate traffic properly for long periods of time. This is specifically problematic when the total demand is between the maximum congested and uncongested flow rates as travel times may potentially be over- or underestimated depending on prevailing traffic conditions. Here, the authors simulate traffic flow in a bottleneck with a combined car-following and lane-changing model and use data from the 405 freeway near Irvine, CA to calibrate the model parameters. The calibrated model tracks closely the observed data and predicts accurately the capacity drop phenomenon.
conference paper
conference paper
High-Occupancy Vehicle (HOV) lanes have been regarded as a cost-effective and environmentally friendly option to help move people along congested routes in metropolitan areas. HOV lanes can be categorized as continuous-access and limited-access based on accessibility. This paper focused on the comparison of the operational performance of four study sites in which conversion of HOV lanes from limited-access to continuous-access has taken place. This paper proposed a traffic flow fundamental diagram based approach in which a statistical approach was applied to estimate the traffic flow fundamental diagram parameters, including free-flow speed, critical volume, critical volume and shockwave speed, for the study. The general-purpose lanes’ traffic flow fundamental diagram parameters before and after the conversion were further used to evaluate the performance of the HOV lane conversion. Results show that (1) the HOV lane conversion leads to a faster shockwave speed on general-purpose lanes during the traffic congestion and thus a freeway with continuous-access HOV lane would see congestion clear faster; (2) the performance of the critical volume and critical occupancy after conversion is site-specific and influenced by the local geometric attributes and associated traffic patterns
