scholarly journals Inferring the causal effect of work zones on crashes: methodology and a case study

Author(s):  
Zhuoran Zhang ◽  
Burcu Akinci ◽  
Sean Qian
Keyword(s):  
2021 ◽  
Author(s):  
Dan DIAO ◽  
DIAO Fang ◽  
XIAO Bin ◽  
Ning LIU ◽  
Fengjuan LI ◽  
...  

Abstract Both gestational diabetes mellitus(GDM) and pregnancy induced hypertension (PIH) would influence the gestation significantly. However, the causation between these two symptoms remains speculative. 16,404 pregnant women were identified in Harbin, China in this study. We investigated the evaluate the causal effect of GMD on PIH based on the statistic inference theory. The statistical results indicated that GDM might cause PIH. Also, this case study demonstrated that the decrease temperature might also cause hypertension during pregnancy, and the prevalence rate of GDM increased with age. However, the prevalence of diabetes did not show a remarkable difference in varied areas and ages. This study could provide some essential information that will help to investigate the mechanism for GDM and PIH.


Author(s):  
Anitza Geneve

There is a need to understand the phenomenon of women's under-representation in the Australian Digital Content Industry (DCI) workforce. This chapter presents the findings from an Australian case study where both women working in the industry and industry stakeholders were interviewed for their insight into the influences on women's participation. The rich empirical data and findings from the case study are interpreted using the Acts of Agency theory—an original theory by the author of this chapter. As the chapter reveals there are five ‘Acts of Agency' (containing 10 agent-driven mechanisms) identified as influencing women's participation. Agent-driven mechanisms recognise the causal effect of people themselves; that is, the role individuals play in their participation.


Author(s):  
Ali Jafarnejad ◽  
John Gambatese ◽  
Salvador Hernandez

Radar speed signs (RSSs) are a measure for reducing traffic flow speeds through work zones. The influence of truck-mounted RSSs on vehicle speed was evaluated for mobile maintenance operations in two multilane maintenance work zones in Oregon. In each case study, two periods of testing were conducted: one with the RSS display turned on (treatment) and one without the RSS display turned on (control), and vehicle speeds were recorded. Descriptive statistics were used to summarize collected data, and a two-sample t-test was applied to each case study to compare the speed difference between control and treatment cases. The findings indicate that vehicle speeds are typically lower and that there is less variation in speeds between adjacent vehicles with the RSS turned on. RSSs are thus promising devices for controlling vehicle speed and making work zones safer for motorists and workers.


2021 ◽  
Vol 33 (1) ◽  
pp. 49-59
Author(s):  
Mojtaba Mousazadeh Gilandeh ◽  
Sari Sharif Ali ◽  
Mohammad Javad Goodarzi ◽  
Nahid Amini ◽  
Hassan Latifi

In this study, the traffic parameters were collected from three work zones in Iran in order to evaluate the queue length in the work zones. The work zones were observed at peak and non-peak hours. The results showed that abrupt changes in Freeway Free Speed (FFS) and arrival flow rate caused shockwaves and created a bottleneck in that section of the freeway. In addition, acceleration reduction, abrupt change in the shockwave speed, abrupt change in the arrival flow rate and increase in the percentage of heavy vehicles have led to extreme queue lengths and delay. It has been found that using daily traffic data for scheduling the maintenance and rehabilitation projects could diminish the queue length and delay. Also, by determining the bypass for heavy vehicles, the delay can be significantly reduced; by more than three times. Finally, three models have been presented for estimating the queue length in freeway work zones. Moreover, the procedure shown for creating a queue length model can be used for similar freeways.


Author(s):  
Andrew Berthaume ◽  
Ian Berg ◽  
Rebecca Kiriazes ◽  
Brian O’Donnell ◽  
Stephen Zitzow-Childs ◽  
...  

Freeway work zones can have significant safety and operational impacts. To mitigate these, planners and engineers rely on accurate simulation tools to assess various work zone design and scheduling alternatives. Microsimulation models are often used to predict traffic conditions along freeways, however, they were not created to replicate car-following through work zones and therefore cannot be used to accurately predict work zone impacts. So that practitioners can use microsimulation to better predict work zone impacts, FHWA created the Work Zone Driver Model v1.0 (FHWA v1.0) software that overrides car-following in commercial microsimulation software packages for work zone segments. FHWA v1.0 was tested in a 2017 case study. Results showed acceptable performance, however, there were opportunities to improve the software’s usability and accuracy. Findings were used to upgrade the software and create the FHWA Work Zone Driver Model v2.0 (FHWA v2.0). This paper demonstrates the enhanced capabilities of FHWA v2.0 by interfacing with VISSIM and recreating the 2017 case study, testing its performance along the same interstate work zone in Springfield, MA. FHWA v2.0’s performance was compared with field data, with Wiedemann 99 (W99), and with FHWA v1.0. Performance metrics were selected to align with state departments of transportation (DOTs) work zone management efforts. Results show improved performance from FHWA v2.0 as it predicted queue lengths, queue locations, and travel speeds more accurately than FHWA v1.0 and W99. The enhanced software also addressed some of the variability and merging issues described in the 2017 case study. Next steps are described.


Author(s):  
Grady Carrick ◽  
Sivaramakrishnan Srinivasan ◽  
Khajonsak Jermprapai

Safety service patrols are a proven strategy to mitigate the effects of traffic incidents through quick clearance, incident management, and assistance to other incident responders like police, fire, emergency medical services, and towing. As encountered by other responders, working on or near roadways presents unique hazards for safety service patrol vehicles and operators. Road Rangers are Florida’s branded safety service patrols and, as a mature program with over 100 beats, a suitable case study for safety. This research combined an analysis of Road Ranger traffic crash data for 3 years with a comprehensive safety survey of more than 200 operators to determine safety characteristics related to service patrols. Comparing 200 Road Ranger traffic crashes from 2014 through 2016 with all Florida freeway crashes for the same time period revealed that Road Ranger crashes are five times more likely to involve a parked vehicle, and involve two or more vehicles 95% of the time. Pedestrian involvement, nighttime, shoulder locations, and work zones have higher representation for Road Ranger crashes, but weather is not a factor. Alcohol is three times more likely, drug use five times more likely, and distraction slightly higher when Road Ranger vehicles are struck. A survey of 217 Road Ranger drivers revealed that they are keenly aware of important safety topics like high-visibility safety apparel, non-traffic side vehicle approaches, and the dangers of working where there is limited lateral buffer space. Drivers overwhelmingly believe that they have the training and equipment necessary to do their jobs safely.


2012 ◽  
Author(s):  
Calvert W. Jones

"This working paper presents the results of an intensive case study of education reform to support the development of a post-petroleum, knowledge-based economy in the United Arab Emirates. The case study is part of a larger research project exploring the ways in which state leaders may cultivate engaged citizens who are willing and able to contribute to the development of their countries, particularly in the contemporary era of heightened globalization and intense economic competition. Building on existing theory and empirical work, the case study identifies and measures attitudes that are believed to facilitate knowledge-intensive growth within one country, such as achievement motivation, risk-taking propensity, civic duty, willingness to invest in a promising business idea, and trust and social capital. For both policymakers and researchers, the case study offers a rich portrait of one strategy that state leaders may use to help foster knowledge-intensive economic development. The case study uses a quasi-experimental research methodology that compares UAE students’ attitudes in a new type of school (“treatment” schools) with UAE students’ attitudes at regular government schools (“control” schools). The new type of school has been developed as part of the country’s larger movement of education reform to support a post-petroleum, knowledge-based economy. The working paper presents findings on the major differences between students’ attitudes at the two types of schools and uses a difference-in-differences (DD) approach to estimate the causal effect of the treatment schools on students’ attitudes in these areas. Key findings include: • Students in the treatment schools reported significantly higher levels of achievement motivation, willingness to take risks, willingness to invest in a promising business idea, and social capital, compared with students in regular government schools. • Students in the treatment schools reported significantly higher levels of civic-mindedness relative to students in regular government schools. • Positive, significant DD estimates of the causal effect of treatment schools on students’ levels of nationalism and pride in the UAE were also found, suggesting that treatment schools are successfully promoting these types of attitudes in UAE youth. • Respect from friends and personal interest, or “a job I like,” were students’ highest priorities in selecting a job across both types of schools; treated students consider “contributing to UAE society” almost as important. • The data suggest that treatment schools are increasing the degree to which UAE youth value determination and perseverance, based on positive and significant DD treatment effect estimates for these variables." تعرض ورقة العمل هذه نتائج دراسة حالة مكثفة لإصلاح التعليم من أجل دعم تطوير اقتصاد قائم على المعرفة لمرحلة ما بعد النفط في دولة الإمارات العربية المتحدة .


2017 ◽  
Vol 47 (3) ◽  
pp. 558-584 ◽  
Author(s):  
Ivo Bischoff ◽  
Peter Bönisch ◽  
Peter Haug ◽  
Annette Illy

The existing empirical literature on the impact of vertical grants on local public-sector efficiency yields mixed results. Given the fact that vertical financial equalization systems often reduce differences in fiscal capacity, we argue that empirical studies based on cross-sectional data may yield a positive relationship between grants and efficiency of public service production even when the underlying causal effect is not. We provide a simple illustrative theoretical model to show the logic of our argument and illustrate its relevance by an empirical case study for the German state of Saxony-Anhalt. We show that our main argument of an inference-disturbing effect applies to those existing studies that are more optimistic about the impact of vertical grants. Finally, we argue that it may disturb the inference drawn from studies in a number of other countries where vertical grants—intended or not—concentrate in fiscally weak municipalities.


Sign in / Sign up

Export Citation Format

Share Document