Dataset Information

Will higher traffic flow lead to more traffic conflicts? A crash surrogate metric based analysis.

ABSTRACT: In this paper, we aim to examine the relationship between traffic flow and potential conflict risks by using crash surrogate metrics. It has been widely recognized that one traffic flow corresponds to two distinct traffic states with different speeds and densities. In view of this, instead of simply aggregating traffic conditions with the same traffic volume, we represent potential conflict risks at a traffic flow fundamental diagram. Two crash surrogate metrics, namely, Aggregated Crash Index and Time to Collision, are used in this study to represent the potential conflict risks with respect to different traffic conditions. Furthermore, Beijing North Ring III and Next Generation SIMulation Interstate 80 datasets are utilized to carry out case studies. By using the proposed procedure, both datasets generate similar trends, which demonstrate the applicability of the proposed methodology and the transferability of our conclusions.

SUBMITTER: Kuang Y

PROVIDER: S-EPMC5546583 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Will higher traffic flow lead to more traffic conflicts? A crash surrogate metric based analysis.

Kuang Yan Y Qu Xiaobo X Yan Yadan Y

PloS one 20170807 8

In this paper, we aim to examine the relationship between traffic flow and potential conflict risks by using crash surrogate metrics. It has been widely recognized that one traffic flow corresponds to two distinct traffic states with different speeds and densities. In view of this, instead of simply aggregating traffic conditions with the same traffic volume, we represent potential conflict risks at a traffic flow fundamental diagram. Two crash surrogate metrics, namely, Aggregated Crash Index a ...[more]

PMID: 28787022

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Project description:Background: Road traffic injuries are a significant and increasing public health burden in Nepal, but there is no national coverage of regulated and standardized emergency medical service systems. Therefore, this study was designed to develop a first responder trauma training program for the Nepal traffic police and to evaluate the feasibility of its delivery and follow up. Methods: A training needs assessment with traffic-police officers in a single district of Nepal informed the development of a 3-day first-response course which was provided to officers in May 2019. Participants were supplied with a trauma-pack and asked to complete a report form when first-responder skills were used. Knowledge and confidence face-to-face surveys were used before and after training to assess learning, and were repeated at 6 months to assess retention of knowledge. The surveys at 6 months assessed the factors affecting application of first response skills. Results: Most (97%) participants believed giving first-aid was part of their responsibilities and 95% had experience of transporting road crash victims to hospital with a range of injuries. Low levels of first-aid training and variable course content were reported. Knowledge and confidence scores improved post-intervention but were reduced at 6-months. During attendance at 303 road crashes in the 6-months follow-up period, 44% of the participants self-reported using at least one skill from the course; applying them on 92 occasions. Incident report-forms were frequently not completed. Barriers to providing treatment included: the patient already en-route to hospital when police arrived at scene; resistance to providing care from relatives or bystanders; and competing police duties (e.g., traffic management). Conclusions: Delivering a first-response training program for traffic-police in Nepal is feasible. Knowledge was retained and used, and skills were in frequent demand. A study of effectiveness and cost-effectiveness appears warranted to determine if extending the training to other districts can improve outcomes in road traffic injury patients in the absence of formal emergency medical services.

Project description:BackgroundRoemer's Law, a widely cited principle in health care policy, states that hospital beds that are built tend to be used. This simple but powerful expression has been invoked to justify Certificate of Need regulation of hospital beds in an effort to contain health care costs. Despite its influence, a surprisingly small body of empirical evidence supports its content. Furthermore, known geographic factors influencing health services use and the spatial structure of the relationship between hospital bed availability and hospitalization rates have not been sufficiently explored in past examinations of Roemer's Law. We pose the question, "Accounting for space in health care access and use, is there an observable association between the availability of hospital beds and hospital utilization?"MethodsWe employ an ecological research design based upon the Anderson behavioral model of health care utilization. This conceptual model is implemented in an explicitly spatial context. The effect of hospital bed availability on the utilization of hospital services is evaluated, accounting for spatial structure and controlling for other known determinants of hospital utilization. The stability of this relationship is explored by testing across numerous geographic scales of analysis. The case study comprises an entire state system of hospitals and population, evaluating over one million inpatient admissions.ResultsWe find compelling evidence that a positive, statistically significant relationship exists between hospital bed availability and inpatient hospitalization rates. Additionally, the observed relationship is invariant with changes in the geographic scale of analysis.ConclusionsThis study provides evidence for the effects of Roemer's Law, thus suggesting that variations in hospitalization rates have origins in the availability of hospital beds. This relationship is found to be robust across geographic scales of analysis. These findings suggest continued regulation of hospital bed supply to assist in controlling hospital utilization is justified.

Project description:BACKGROUND:Law enforcement traffic stops are one of the most common entryways to the US justice system. Conventional frameworks suggest traffic stops promote public safety by reducing dangerous driving practices and non-vehicular crime. Law enforcement agencies have wide latitude in enforcement, including prioritization of stop types: (1) safety (e.g. moving violation) stops, (2) investigatory stops, or (3) economic (regulatory and equipment) stops. In order to prevent traffic crash fatalities and reduce racial disparities, the police department of Fayetteville, North Carolina significantly re-prioritized safety stops. METHODS:Annual traffic stop, motor vehicle crash, and crime data from 2002 to 2016 were combined to examine intervention (2013-2016) effects. Fayetteville was compared against synthetic control agencies built from 8 similar North Carolina agencies by weighted matching on pre-intervention period trends and comparison against post-intervention trends. RESULTS:On average over the intervention period as compared to synthetic controls, Fayetteville increased both the number of safety stops +?121% (95% confidence interval?+?17%, +?318%) and the relative proportion of safety stops (+?47%). Traffic crash and injury outcomes were reduced, including traffic fatalities -?28% (-?64%, +?43%), injurious crashes -?23% (-?49%, +?16%), and total crashes -?13% (-?48%, +?21%). Disparity measures were reduced, including Black percent of traffic stops -?7% (-?9%, -?5%) and Black vs. White traffic stop rate ratio?-?21% (-?29%, -?13%). In contrast to the Ferguson Effect hypothesis, the relative de-prioritization of investigatory stops was not associated with an increase in non-traffic crime outcomes, which were reduced or unchanged, including index crimes -?10% (-?25%, +?8%) and violent crimes -?2% (-?33%, +?43%). Confidence intervals were estimated using a different technique and, given small samples, may be asymmetrical. CONCLUSIONS:The re-prioritization of traffic stop types by law enforcement agencies may have positive public health consequences both for motor vehicle injury and racial disparity outcomes while having little impact on non-traffic crime.

Dataset Information

Will higher traffic flow lead to more traffic conflicts? A crash surrogate metric based analysis.

Publications

Will higher traffic flow lead to more traffic conflicts? A crash surrogate metric based analysis.

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