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Traffic congestion is a major problem in large cities worldwide. This project uses high-frequency data from the Los Angeles metropolitan area combined with an instrument that varies spatially and temporally to estimate the causal impact of an additional vehicle mile traveled on travel times. Specifically, the research team exploits the network structure of the Los Angeles highway system and uses crashes on close alternative routes as exogenous shocks to traffic demand. To do so, the team relies on Google Maps to determine the ideal route and alternatives for over 19,000 real-world commutes. The researchers estimate that at peak times an additional trip reduces speed by, on average, 0.22%. They find the optimal toll at peak times is 33 cents per mile, with the toll being lower, even zero, off-peak. The researchers show how this toll varies over space and time, as well as report on its distributional effects. This toll would more than double highway speeds during peak times and only requires reducing vehicle miles traveled (VMT) at the peak by 10%. The resulting social welfare gains are over two billion dollars per year.View the NCST Project Webpage

The shift to student engagement in scientific and engineering practices to learn science provides opportunities for science learning and language learning to occur in tandem. These opportunities also pose new challenges for elementary pre-service teachers (PSTs) since literacy methods courses have been presented separately from science methods courses. We integrated a disciplinary literacy framework in a science methods course to help elementary PSTs understand the synergistic connections between literacy and science teaching. The purpose of this study was to examine elementary PSTs' understanding of the use of science-specific literacy strategies to support science teaching and learning through three points of observation. Findings from three data sources indicated that PSTs showed a developing understanding of the role of disciplinary literacy in supporting student engagement in science practices and learning disciplinary core ideas. Implications for future uses of a disciplinary literacy framework for teaching and learning science and elementary PSTs' science preparation are presented.

This study presents the recollections of 12 successful women in science during their school years before postsecondary education. The participants shared detailed descriptions of their science experiences through three semi-structured interviews. An identity works conceptual framework consisting of figured worlds, positioning, and agency constructs to portray the complex dynamics of their experiences was used to analyze the data. The following four themes emerged from the data analysis: participants had an early interest in mathematics and science; they were "stubbornly" persistent in science-figured worlds; they engaged in science-figured worlds beyond school; and they positioned themselves as science leaders. These findings add to the evolution of science identity development theoretical models because they are from a nondeficit perspective. Participants engaged in identity work that advanced their science identities despite the gender biases in science-figured worlds. From a practical stance, girls and women could employ the agentic and positive positioning identity work that the findings show to develop their science identity in educational contexts. Science educators and researchers are encouraged to structure figured worlds where girls feel empowered to enact identity work to build strong science identities.

This design-based research project reports on three multilevel networks that were focused on implementing the Next Generation Science Standards (NGSS). Given the recent attention to understanding infrastructure to craft coherence in NGSS implementation, this research investigated how these networks iteratively re-designed infrastructure as they engaged in implementing the NGSS. This focus is particularly important in the current context of NGSS implementation since needed infrastructure did not accompany the dissemination of the standards. The three networks were the following: mentor teachers, district specialists, and interim assessment specialists. Qualitative cases based on recordings of network working sessions, interviews with members, and artifacts of their work were generated for each network and then compared and contrasted. Findings show the work on infrastructure re-design across the networks not only involved identifying useful NGSS-designed resources and frameworks, but also translating these into meaningful supports or scaffolds that could ultimately lead to productive forms of engagement for either supporting teacher professional learning or student learning. Also, collegial workspaces were beneficial for institutionalizing networks' foci by creating spaces for all actors to share their experiences, challenges, and needs. This meant focusing on curriculum and instructional routines for mentor teachers, focusing on NGSS instructional principles for district leaders, and focusing on the development of an interim assessment practice brief for interim assessment leaders--foci identified as central to and immediately applicable in the day-to-day work of the respective network members.