Assessment of the impact of changes in transit systems using intervention analysis

1988 ◽  
Vol 22 (1) ◽  
pp. 55-67 ◽  
Author(s):  
John J. Considine ◽  
Jack Narayan
Author(s):  
Stephanie Pollack ◽  
Anna Gartsman ◽  
Timothy Reardon ◽  
Meghna Hari

The American Public Transportation Association's use of a “land use multiplier” as part of its methodology for calculating greenhouse gas reduction from transit has increased interest in methodologies that quantify the impact of transit systems on land use and vehicle miles traveled. Such transit leverage, however, is frequently evaluated for urbanized areas, although transit systems serve only a small proportion of those areas. If transit leverage is stronger in areas closer to transit stations, studies based on larger geographies may underestimate land use and travel behavior effects in transit-served areas. A geographic information system–based data set was developed to understand better the leverage effects associated with the mature and extensive Massachusetts Bay Transportation Authority transit system in areas proximate to its stations throughout Metropolitan Boston. The region was divided into the subregion that was transit-proximate (within a half mile of a rapid transit station or key bus route), the portion that was commuter rail–proximate, and the remaining 93.3% of the region that was not proximate to high-frequency transit. Households in the transit-proximate subregion were significantly more likely to commute by transit (and walking or biking), less likely to own a car, and drove fewer miles than households in the non-transit-served areas of the region. Commuter rail–proximate areas, although denser than the region as a whole, exhibited more driving and car ownership than regional averages. Given these spatial and modal variations, future efforts to understand transit leverage should separately evaluate land use and travel effects by mode and proximity to transit stations.


2021 ◽  
Vol 295 ◽  
pp. 126441
Author(s):  
Hongyu Chen ◽  
Limao Zhang ◽  
Qiong Liu ◽  
Hongtao Wang ◽  
Xiaosong Dai

Author(s):  
Angela Ballantyne ◽  
Lorna Rashid ◽  
Rebecca Pattenden

Background Maternal serum free beta human chorionic gonadotrophin (free β-hCG) is used as a biomarker in first trimester screening for fetal Down’s syndrome. Production of free β-hCG can occur in vitro in a time- and temperature-dependent manner; thus, the current Scottish screening protocol states samples must be received by the laboratory within 72 h. To assess the validity of the protocol, an audit was conducted to determine the impact of transit time on maternal serum free β-hCG multiple of median (MoM) values in the Scottish screened population. Methods Corrected MoM values from antenatal screening carried out over one year (April 2017 to March 2018) were stratified according to sample transit time and compared. To investigate possible environmental temperature effects, the data were split according to season and maternal serum free β-hCG concentrations from summer and winter compared. Results Of the 28,368 samples included in the study, 24,368 were received on the day of phlebotomy or after one day in transit. Only 1.5% of samples were received after 3 days in transit. The difference in maternal serum free β-hCG MoM values due to transit time was not significant. No statistical difference was found between maternal serum free β-hCG concentrations from samples collected in summer and winter months. Conclusion The current sample receipt protocol in use by the Scottish Down’s syndrome screening programme is fit for purpose.


2021 ◽  
Vol 26 ◽  
Author(s):  
Iram Osman ◽  
Shaista Hamid ◽  
Veena S. Singaram

Background: During the coronavirus disease 2019 (COVID-19) pandemic, health professionals were pushed to the front line of a global health crisis unprepared and resource constrained, which affected their mental well-being.Aim: This study aimed to investigate the effectiveness of a brief online mindfulness-based intervention (MBI) on stress and burnout for health professionals training and working in South Africa during the COVID-19 crisis.Setting: The context of the study is the overburdened, under-resourced health care system in South Africa during a global pandemic.Methods: A mixed method framework was adopted for this study. The quantitative data was analysed using descriptive analysis and the participants’ qualitative experiences were interpreted using interpretative phenomenological analysis.Results: Forty-seven participants took part in this study. The study found a statistically significant (p 0.05) reduction in stress levels and emotional exhaustion as well as an increase in mindful awareness and feelings of personal accomplishment after the intervention. The participants’ shared experiences were analysed in two parts. The pre-intervention analysis presented with central themes of loss of control and a sense of powerlessness because of COVID-19. The post-intervention analysis comprised themes of a sense of acquired control and empowerment through increased mindfulness.Conclusions: The study found that a brief online MBI can be associated with reduced levels of stress and burnout as well as an increased sense of control and empowerment, felt both personally and professionally, during a global crisis.Contribution: The impact of an online MBI for health care professionals amidst a pandemic has not been previously documented.


2010 ◽  
Vol 13 (3) ◽  
pp. 79-100 ◽  
Author(s):  
Eirini Veliou ◽  
Konstantinos Kepaptsoglou ◽  
Matthew Karlaftis

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bowen Hou ◽  
Shuzhi Zhao ◽  
Huasheng Liu ◽  
Jin Li

Traditional transit systems are susceptible to unexpected costs and delays due to unforeseen events, such as vehicle breakdowns. The randomness of these events gives the appearance of an imbalance in the number of operating vehicles and of unreliable transit services. Therefore, this paper proposes the queueing theory as a means to characterize the state of any given transit system considering the risk of vehicle breakdowns. In addition, the proposed method is used to create an optimized model for reserve fleet sizes in transit systems, in order to ensure the reliability of the transit system and minimize the total cost of any transit system exposed to the risks of vehicle breakdowns. The optimization is conducted based on the two main characteristics of all bus systems, namely, operator costs and user costs, in both normal and disruptive situations. In addition, the situations in our optimization are generated in scenarios that have a certain degree of probability of experiencing delays. This paper formulates such an optimization model, presents the formulation solution method, and proves the validity of the proposed method.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
R. Chazya ◽  
J. B. Muma ◽  
K. K. Mwacalimba ◽  
E. Karimuribo ◽  
E. Mkandawire ◽  
...  

A qualitative risk assessment was performed to evaluate the risk of introducing Peste des petits ruminants virus into northern Zambia from Tanzania via live goat trade. Data was collected during a mission to Tanzania and northern Zambia and also from literature and interviews with experts. The risk of PPRV introduction was evaluated as a function of the probability of hazard (PPRV) release, exposure of susceptible hosts, and the consequences of spread using the following parameters: prevalence of infection, volume of trade, C-ELISA and quarantine screening missing an infected animal, PPRV viability (remaining infective) in transit, and the virus potential for infection. The magnitude of the consequences was derived from the probability of transmission and spread and the impact of PPRV introduction and establishment. Accordingly, the probability of occurrence of PPRV in northern Zambia from Tanzania was rated as “high” and the economic consequences were also rated as “high.” Finally, the overall risk of introducing PPRV into northern Zambia from Tanzania at the time of the assessment was rated “high.” It was concluded that import of goats and sheep be prohibited until efficient and adequate measures to reduce the risk have been put in place.


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