Safety Effects of Low-Cost Systemic Safety Improvements at Signalized and Stop-Controlled Intersections

Author(s):  
Thanh Q. Le ◽  
Frank Gross ◽  
Timothy Harmon

Packages of intersection treatments—including signing, pavement marking, and signal enhancements—were installed at many signalized and stop-controlled intersections in South Carolina. This study evaluated the overall safety-effectiveness of the concurrent implementation of these systemic low-cost treatments as part of the FHWA Evaluations of Low Cost Safety Improvements Pooled Fund. The data set included both urban and rural three-leg and four-leg intersections with two or four lanes on the major road. The study employed an empirical Bayes before-and-after analysis. The aggregate results indicate reductions for all crash types analyzed in this study. For signalized intersections, the crash modification factors (CMFs) are 0.955, 0.893, 0.974, 0.883, and 0.969 for total, fatal and injury, rear-end, right-angle, and nighttime crashes, respectively. The CMFs for fatal and injury and right-angle crashes are statistically significant at the 95% confidence level and the CMF for total crashes is statistically significant at the 90% confidence level. For stop-controlled intersections, the CMFs are 0.917, 0.899, 0.933, 0.941, and 0.853 for total, fatal and injury, rear-end, right-angle, and nighttime crashes, respectively. All CMFs for stop-controlled intersections are statistically significant at the 95% confidence level. An economic analysis shows that systemic, low-cost intersection treatments are cost-effective with conservative benefit–cost ratio estimates of 4.1 for total crashes at signalized intersections and 12.4 for total crashes at stop-controlled intersections.

Author(s):  
Mingjian Wu ◽  
Karim El-Basyouny ◽  
Tae J. Kwon

Speeding is a leading factor that contributes to approximately one-third of all fatal collisions. Over the past decades, various passive/active countermeasures have been adopted to improve drivers’ compliance to posted speed limits to improve traffic safety. The driver feedback sign (DFS) is considered a low-cost innovative intervention that is being widely used, in growing numbers, in urban cities to provide positive guidance for motorists. Despite their documented effectiveness in reducing speeds, limited literature exists on their impact on reducing collisions. This study addresses this gap by designing a before-and-after study using the empirical Bayes method for a large sample of urban road segments. Safety performance functions and yearly calibration factors are developed to quantify the sole effectiveness of DFS using large-scale spatial data and a set of reference road segments within the city of Edmonton, Alberta, Canada. Likewise, the study followed a detailed economic analysis based on three collision-costing criteria to investigate if DFS was indeed a cost-effective intervention. The results showed significant collision reductions that ranged from 32.5% to 44.9%, with the highest reductions observed for severe speed-related collisions. The results further attested that the benefit–cost ratios, combining severe and property-damage-only collisions, ranged from 8.2 to 20.2 indicating that DFS can be an extremely economical countermeasure. The findings from this study can provide transportation agencies in need of implementing cost-efficient countermeasures with a tool they need to design a long-term strategic deployment plan to ensure the safety of traveling public.


2017 ◽  
Vol 2620 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Anuj Sharma ◽  
Edward Smaglik ◽  
Sirisha Kothuri ◽  
Oliver Smith ◽  
Peter Koonce ◽  
...  

To improve the safety of people walking at particular signalized intersections, traffic signal engineers may implement leading pedestrian intervals (LPIs) to provide pedestrians with a walk signal for a few seconds before the parallel vehicular green indication. Previous before-and-after studies and simple economic analyses have indicated that LPIs are low-cost tools that can reduce vehicle–pedestrian conflicts and crashes at some signalized intersections. Despite this evidence, municipalities have little guidance for when to implement LPIs. A marginal benefit–cost framework is developed with quantitative metrics and extends the concept of traffic conflicts and marginal safety–delay trade-offs to analyze the appropriateness of implementing an LPI at specific signalized intersections. The method provides guidance to help quantify the probability of a conflict occurring and direction on whether to implement an LPI at a given location from macroscopic-level inputs, including number of turning movements, crash data, and geometry. A case study with sample data indicated that an LPI was cost-effective for the scenario presented.


2021 ◽  
Author(s):  
Ahmed GH Mansour ◽  
Talal Gamadi ◽  
Hussain R Saoyleh

Abstract The objective of this study is to determine the effects of the concentration of injected gases on recovery factors. CO2 has been used for flooding because it requires low injection pressures to achieve miscibility. However, the availability of CO2 is an issue. CO2 required for the process is not sufficient for the reservoir under consideration. Moreover, its benefit-cost ratio (b/c) represents another issue; higher volumes of CO2 increases the economic expenditures. An alternative is to inject lean gas or nitrogen along with CO2 to achieve better recoveries at optimum costs and suitable pressure. Slim tube simulation using a commercial simulator is utilized to measure the minimum miscibility pressure (MMP) of an injected gas mixture. The mixture contains CO2/N2 or CO2/lean gas. Using different concentrations in the injected mixture, an effect on the recovery factor is studied. The first 30 runs have 100% concentration of each individual gases i.e. N2, CO2 and lean gas. Based on these runs, the simulation model is validated using the co-relations present in the literature. Gas mixtures of CO2/N2 and CO2/lean gas were then simulated using the compositional model to test the effect on MMP by varying the concentration of each gas in the mixture. By changing the volumes of the gas in the injected mixture, we can find the optimum concentration of each component in the mixture in terms of MMP. From the results obtained through simulation, it can be deduced that higher percentages of CO2 in the mixture would result in reduced minimum miscibility pressure. The addition of a secondary slug to the injected CO2 fluid increases the pressure required to achieve miscibility. Of N2 and Lean gas, Lean gas provided better results as it showed low miscibility pressure responses compared to the same amount of N2 gas. For example, for a case, 50% CO2 and 50 %N2 or lean gas mixture, the MMP for the lean gas mixture is 3500 Psi, while for N2 mixture it was 4667 Psi. However, lean gas is expensive as compared to N2 and N2 is easily available. N2, if used in optimum concentration along with CO2 can produce greater recoveries keeping the process cost-effective while satisfying other constraints. CO2 is widely used for miscible injection, but it presents problems like costs, corrosion, and asphaltene deposition etc. The study can give an idea of the success of carrying out EOR through gas flooding by using N2 and CO2 to enhance recovery at low cost. N2 is easily available from air and it is cheap.


Author(s):  
Raghavan Srinivasan ◽  
Bo Lan ◽  
Daniel Carter ◽  
Sarah Smith ◽  
Bhagwant Persaud ◽  
...  

The pedestrian countdown signals (PCS) treatment involves the display of a numerical countdown that shows how many seconds are left in the flashing DON’T WALK interval. Although many studies have attempted to evaluate the safety of PCS, the results have been inconsistent for many reasons, including inadequate sample size and the inability to control for possible bias from regression to the mean and from exposure. This study performed a before-after empirical Bayes analysis using data from 115 treated intersections in Charlotte, North Carolina and 218 treated intersections in Philadelphia, Pennsylvania to evaluate the safety effects of PCS. The evaluation also included 136 reference intersections in Charlotte, and 597 reference intersections in Philadelphia. Following the implementation of PCS, total crashes decreased by approximately 8% and rear-end crashes decreased by approximately 12%, and these reductions were statistically significant at the 95% confidence level. Pedestrian crashes decreased by about 9% and this reduction was statistically significant at the 90% confidence level. Economic analysis revealed a benefit-cost ratio of 23 with a low of 13 and a high of 32.


2020 ◽  
pp. 096228022095817
Author(s):  
Linchen He ◽  
Linqiu Du ◽  
Zoran Antonijevic ◽  
Martin Posch ◽  
Valeriy R Korostyshevskiy ◽  
...  

Previous work has shown that individual randomized “proof-of-concept” (PoC) studies may be designed to maximize cost-effectiveness, subject to an overall PoC budget constraint. Maximizing cost-effectiveness has also been considered for arrays of simultaneously executed PoC studies. Defining Type III error as the opportunity cost of not performing a PoC study, we evaluate the common pharmaceutical practice of allocating PoC study funds in two stages. Stage 1, or the first wave of PoC studies, screens drugs to identify those to be permitted additional PoC studies in Stage 2. We investigate if this strategy significantly improves efficiency, despite slowing development. We quantify the benefit, cost, benefit-cost ratio, and Type III error given the number of Stage 1 PoC studies. Relative to a single stage PoC strategy, significant cost-effective gains are seen when at least one of the drugs has a low probability of success (10%) and especially when there are either few drugs (2) with a large number of indications allowed per drug (10) or a large portfolio of drugs (4). In these cases, the recommended number of Stage 1 PoC studies ranges from 2 to 4, tracking approximately with an inflection point in the minimization curve of Type III error.


2018 ◽  
Vol 69 (5) ◽  
pp. 479 ◽  
Author(s):  
Nauman Ali ◽  
Muhammad Farooq ◽  
Muhammad Ahmad Hassan ◽  
Muhammad Shakeel Arshad ◽  
Muhammad Kamran Saleem ◽  
...  

Agronomic biofortification by seed treatments is a convenient way to harvest improved yields of micronutrient-enriched grains. This 2-year field study was conducted to evaluate the effects of seed priming with zinc (Zn), boron (B) and manganese (Mn) alone and in combinations on stand establishment, grain yield and biofortification of bread wheat (Triticum aestivum L.). Seeds of wheat cv. Faisalabad-2008 were soaked in aerated solutions of 0.5 m Zn, 0.01 m B and 0.1 m Mn, alone and in different combinations, for 12 h. Seed priming with the micronutrients was quite effective in improving stand establishment, yield-contributing traits, grain yield, and straw and grain micronutrient contents during both years. Best stand establishment was achieved from seed priming with Zn+B, followed by seed priming with Zn+Mn. Grain yield improvement from different seed priming treatments was in the order Zn+B > Zn+Mn > Zn > B > Mn > Zn+B+Mn, with respective increases of 34%, 33%, 21%, 19%, 18% and 8% relative to untreated seeds. Seed priming with Zn, B and Mn alone and in combinations also improved the contents of the respective micronutrients in straw and grain. All seed priming treatments were economically profitable except Zn+B+Mn, which was not cost-effective. The highest benefit : cost ratio accrued from seed priming with Zn+B. In conclusion, seed priming with micronutrients was generally cost-effective in meeting the crop micronutrient requirements, and in improving crop stand, grain yield and grain micronutrient contents in bread wheat. Seed priming with Zn+B was the most effective in this regard.


1970 ◽  
Vol 8 (2) ◽  
pp. 271-276 ◽  
Author(s):  
MA Halim ◽  
MA Kashem ◽  
JU Ahmed ◽  
M Hossain

The study was carried out in 5 Upazilas under Chittagong district with a view to analyze the present socio-economic status of RCC farming practices on 100 RCC rearers (Potiya, Raujan, Chandanaish, Anowara and Satkania Upazila). The study showed that, about 39.00 percent of RCC farm owners were landless, 31.00 percent were small and marginal farmers, 17.00 percent were medium and 13.00 percent were large farmers according to their landholding sizes. The cost of rearing RCC per cattle per year was found to be Tk. 17503.76, Tk. 15540.27, and Tk. 33044.03 as cash cost, non cash cost and total cost respectively. The study also revealed that, average daily milk yield, lactation yield and lactation length of RCC were found to be 2.71 liters, 581.61 liters and 215.41 days, respectively. The average per year per cattle gross return of RCC was found Tk. 25390.41. The gross returns over cash cost and full cost basis of rearing per lactation per cattle of RCC were found at Tk 8058.642 and Tk.-7501.53, respectively. The benefit cost ratio on the basis of cash cost and full costs per year per cattle was found 1.47 and 0.77, respectively. The study also revealed that, the rural farmers prefer RCC farming than other breeds due to high conception rate, each year calving, disease resistance, high milk fat per cent and cost effective farming. Keyword: RCC; Cost; Return; Profitability; Disease Occurrences DOI: 10.3329/jbau.v8i2.7937 J. Bangladesh Agril. Univ. 8(2): 271-276, 2010  


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Steve J. Merrill ◽  
Alexander Paz ◽  
Victor Molano ◽  
Pramen P. Shrestha ◽  
Pankaj Maheshwari ◽  
...  

This study provides an economic evaluation for a Land Ferry, which is a rail system capable of carrying trucks and all other types of vehicles, passengers, and cargo. The Land Ferry system involves a sliding loading system to roll heavy loads onto a flatbed; as a result, loading and unloading of all vehicles and cargo could be accomplished simultaneously. The evaluation for this system included (1) the design of a new track alignment over which the Land Ferry system would run, (2) evaluation of various sources of power, (3) estimation of how many local jobs the Land Ferry would generate, and (4) a benefit-cost analysis. It was estimated that the Land Ferry would create over 45,788 temporary jobs in Nevada during the three-year construction period and 318 permanent jobs during operation. The majority of the benefits were attributed to savings in travel time ($356.4 M), vehicle operating costs ($1000.4 M), reduction of accidents ($544.6 M), and pavement maintenance ($503.2 M). These benefits would be a consequence of the shift of trucks from the highway, thus resulting in higher speeds, decrease fuel consumption, and decrease vehicle maintenance costs. The overall benefit-cost ratio of 1.7 implies a cost-effective project.


2014 ◽  
Vol 663 ◽  
pp. 596-603
Author(s):  
Zulhaidi Mohd Jawi ◽  
Aqbal Hafeez Ariffin ◽  
Yahaya Ahmad ◽  
Khairil Anwar Abu Kassim ◽  
Norlen Mohamed ◽  
...  

The newly established New Car Assessment Program for Southeast Asian Countries (ASEAN NCAP) has incorporated Safety Assist Technologies (SATs) in its automobile safety rating scheme. In order for any assessed car to be eligible for the maximum 5-star rating, it should first be equipped with Electronic Stability Control (ESC) and fitted with seatbelt reminder (SBR). However, since these SATs are not being evaluated in their performance by the means of field testing, this paper explains the benefit of having these SATs through Cost-Benefit Analysis (CBA) which help to rationalize the importance of SATs in preventing road accidents or mitigating severity of injuries. Due to data limitation, this preliminary CBA assessment will only be focusing on Malaysia’s situation and is based on published sources and the authors’ best estimates. This study also includes the Cost-Benefit Analysis on Anti-lock Braking System (ABS), which is the basis for ESC technology, in preparation for its inclusion in the future rating scheme to expedite the vision of making ABS as standard fit in all ASEAN’s passenger cars. The preliminary result shows that all technologies – ESC, SBR and ABS – appear to be cost-effective (benefit/cost-ratio > 3) or most likely cost effective (1 < benefit/cost-ratio < 3) in Malaysia’s road safety situation per se.


2020 ◽  
Vol 9 (11) ◽  
pp. e66991110251
Author(s):  
Ana Paula Taboada Sobral ◽  
Sergio de Sousa Sobral ◽  
Glaucia Gurnhak Giacon ◽  
Thalita Molinos Campos ◽  
Anna Carolina Ratto Tempestini Horliana ◽  
...  

Objective: To compare the efficacy of photobiomodulation and occlusal splint in patients with TMD-associated myofascial pain. Material and methods: 23 patients were randomized into 2 groups: laser group (LG) (n = 12) and occlusal splint group (OSG) (n=11). For the LG, laser was applied to 3 points on each side of the face. Twelve applications were made, 2 sessions per week. In the OSG, patients were instructed to use the device during sleep, 8 hours per night, for a period of 6 weeks, and 12 adjustment and follow-up sessions were performed. Patients in both groups were reevaluated 30 days after the end of the treatments. Results: There was a decrease in pain intensity, according to a visual analogue scale, in both groups before and after 1 month (LG, p = 0.008 and OSG p = 0.002), but with no difference between groups. For the quality of life, both treatments had a positive impact, with this impact being higher in the LG compared to the OSG (p <0.05). Regarding the cost-effectiveness analysis, laser was more cost-effective than the occlusal splint in the clinical trial. The incremental cost of the laser was $3,483.45 compared to the splint, but it had a cost ratio of $4,569.02 for controlled pain intensity while the splint showed $6,691.91 ratio for controlled pain intensity. Conclusion: The photobiomodulation was more cost-effective in controlling painful symptoms in patients with TMD and myofascial pain.


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