Study of vehicle speeds on a major highway in Ghana: implication for monitoring and control

OBJECTIVE: Vehicular speeds have been identified to be at the core of road accident severity and frequency globally. Whereas speed control is a fundamental priority and the cornerstone of road safety in the developed world, the subject is at rudimentary stages in most developing countries thus making research into vehicle speeds in developing nations imperative. The main aim of the study was to establish two major speed parameters, namely the mean speed and dispersion, and their implications for more extensive and long-term speed monitoring in Ghana. METHODS: Research workers stationed themselves in a parked car and used a radar gun to unobtrusively measure the travelling speeds of 4,163 vehicles over two 24-hour periods at two separate sites on one of the main inter-urban roads (Accra-Kumasi). Both sites were settled areas with posted speed limits of 50 km/hr. RESULTS: Over 95% of vehicles travelled above the posted speed limit of 50 km/hr. Vehicles on an average travelled at 87 km/hr, (95% CI=87, 88). Variation in speeds was wide, with a standard deviation of 18 km/hr for all classes of vehicles, and with a range of 40 to 187 km/hr. The highest vehicular speed was associated with the private car (97.6+/-18.3 km/hr) followed by large buses (93.6+/-13.3 km/hr) and the least was with heavy trucks (73.8+/-12.9 km/hr). CONCLUSION: The excessive vehicular speeds coupled with the wide speed variations explain in part the high incidence of traffic crashes and fatalities on the Accra-Kumasi highway. An integrated speed monitoring and control program, and realigning the highway to by-pass small and medium settlements would be required as a long-term measure for the reduction of speed-related road traffic crashes, fatalities, and injuries in Ghana.     

Composite indicators for famine early warning systems

Traditional famine early warning systems use a host of indicators to predict food crisis situations, from rainfall and increased rate of marketing of household durables to the behavior of birds and animals. Although many of these indicators are valid in general, limited understanding of the sensitivity and specificity of the distress signals makes food crisis prediction a highly subjective exercise. In order to make the system more effective and credible, we need to identify a limited number of 'composite' indicators, which naturally summarize most relevant food-related information contained in the specific predictors of food crisis. Considering the chronology of the food production and consumption chain, three composite indicators specific to three different stages of the chain have been identified. The satellite data based Normalized Deviation of Vegetative Index (NDVI), prices of major food grains, and malnutrition rates are found to be correlated not only with the quality and quantity of inputs of this process but also with the final outcome. Both NDVI and price data are widely used as important predictors of food crisis by famine warning systems. What we have demonstrated is that improved sensitivity of the indicators is likely to be due to their inherent capability of summarizing information from various specific measures. Child malnutrition rates also summarize inputs and outputs of the food consumption process very effectively, and therefore should be able to predict community level food crisis in an efficient manner. The empirical results confirm this conjecture by showing that malnutrition rates can predict food crisis probability three months into the future with a high degree of specificity. The use of 'composite' indicators not only simplifies the problem of aggregation, but is also likely to yield forecasts that are highly specific and sensitive.     

Environmental and Biological Assessment of Exposure to Benzene in Petroleum Workers

Occupational exposure to benzene was measured in two gasoline marketing terminals and five major refineries in Singapore. A total of 280 workers were monitored over two years. This assessment was carried out with two primary objectives: (1) To find out the extent of occupational exposure to benzene in the petroleum industry in Singapore, (2) To identify suitable biomarkers for monitoring of low levels of benzene exposure. The exposure was measured in five different categories of petroleum and petrochemical workers, i.e., truck drivers, despatch assistant, process operators, oil movements operators and laboratory technicians. The results revealed wide variations in exposure, from 0.01 to 13.6 ppm for personal time weighted average (TWA) exposure over the whole workshift. The exposure of truck drivers appeared to be the highest, with geometric mean (GM) of 1.98 ppm (ranged from 0.25 to 13.6 ppm). The average benzene exposure for process operators was relative low with a GM of 0.04 ppm. Lowest benzene exposure was found in the laboratory technicians, with a GM of 0.02 ppm. As cigarette smoking is known to affect metabolism of benzene, data analyses on the relationships with environmental exposure were conducted only on the 190 nonsmokers. The results showed that urinary trans, trans-muconic acid (ttMA), unmetabolized benzene in urine (UBZ) and benzene in blood (BBZ) were better biomarkers for low level benzene exposure as compared to urinary phenolic metabolites in urine, such as hydroquinone, phenol and catechol.     

An evaluation of the association between vehicle type and the source and severity of pedestrian injuries

To evaluate the effect of vehicle type (passenger vehicle vs. light truck vehicle) on crash trajectory and on the consequent source and severity of pedestrian injury, we analyzed data from the Pedestrian Crash Data Study (PCDS), conducted by National Highway Traffic Safety Administration (NHTSA) from 1994 to 1998. While 62% of the adults in PV (passenger vehicle)-related crashes were carried by the vehicle, such pedestrian-vehicle interaction was observed only in 28% of LTV (light truck vehicle)-adult crashes. Being thrown forward or knocked down were the most common (65%) type of pedestrian-vehicle interactions for LTV-adult crashes. For children, 93% of those struck by LTVs and 46% of those struck by PVs were thrown forward or knocked down. For adults, LTVs were more likely than PVs to cause thorax (37% vs. 20%) and abdomen injuries (33% vs. 18%). For children, LTVs were more likely than PVs to cause injuries to the upper extremity (71% vs. 56%) and abdomen (14% vs. 8%). For adults struck by PVs the most common sources of injury were windshield for head injuries (63%), hood surface for thorax (67%), abdomen (58%), spine (30%), and upper extremity (36%) injuries, and bumper for the lower extremity injuries (60%). The leading causes of injury for adult-LTV crashes were ground for head (39%) and upper extremity (37%) injuries, hood edge for thorax (48%) and abdomen (56%) injuries, hood surface for spine injuries (36%), and bumper for lower extremity injuries (45%). For child-PV crashes, ground was the most common source of face (37%) abdomen (83%), spine (43%), and upper extremity injuries (54%). For children hit by LTVs, 52% of face, 67% of abdomen, 100% of spine, and 60% of upper extremity injuries were attributed to ground contacts. Altogether, the major sources of injury were hood surface and windshield for PV-pedestrian crashes and hood surface and hood edge for LTV-pedestrian crashes. Changes in design, such as altering the geometry and stiffness of front-end structures, might be associated with considerable decrease in the frequency and severity of pedestrian injury.     

In vitro fertilization with non-motile spermatozoa of the brown shrimp Penaeus aztecus

The sperm of the brown shrimp Penaeus aztecus are nonflagellated and non-motile. In vitro fertilization can be obtained when mature eggs removed from female shrimp are added to dense sperm suspensions in seawater and agitated in a manner simulating natural spawning.     

Reducing primary and secondary impact loads on the pelvis during side impact

OBJECTIVE: The objective of the study was to determine which vehicle factors are significantly related to pelvic injury in side impact collisions. Identification of relevant parameters could aid in the reduction of these injuries. METHOD: Side impact crashes from the CIREN database were separated into those in which the occupant sustained a pelvic fracture and those in which no pelvic fracture occurred, although all occupants had serious injuries. A multibody MADYMO model was created of a USDOT SINCAP (U.S. Department of Transportation Side Impact New Car Assessment Program) test of a vehicle with a large center console. RESULTS: From a study of 113 side impact crashes in the ciren database, nearside occupants with pelvic fractures (n = 78) had (i) more door intrusion (mean, 37 vs. 32 cm, p = 0.02) than those who had serious injuries, but not pelvic fractures (ii) a greater likelihood that the lower border of the door intruded more than the upper part (40% vs. 18%, p < 0.025); and (iii) a greater likelihood that their vehicle had a center console (47 vs. 17%, p < 0.005). Other parameters such as occupant age, weight, gender, vehicle weight, and struck vehicle speed change were not significantly different. MADYMO modeling showed that with a center console, an initial positive pelvic acceleration occurred at about 30 msec, followed at about 45 msec by a second acceleration peak in the opposite direction. Reducing console stiffness reduced the second acceleration but not the initial peak. Allowing the seat to translate laterally when contacted by the door reduced the initial pelvic acceleration by 50% and eliminated the second acceleration peak. CONCLUSIONS: Redesigning the center console using less stiff materials and allowing some lateral translation of the seat could aid in reducing pelvic injuries in side impact collisions.     

Look at groundwater quality to set VOC cleanup levels

In 1981, the Arizona Department of Health Services (ADHS) discovered groundwater contamination by solvents and chromium at the Phoenix Goodyear Airport (PGA), just outside the city of Phoenix. ADHS and the U.S. EPA sampled the site for the next two years, finding that eighteen of their wells were contaminated with trichloroethene (TCE), six exceeding ADHS's action level of five micrograms per liter (μg/l). In 1983, the PGA site was added to the National Priorities List, and, in 1984, EPA began a $3 million remedial investigation, focusing on soils and groundwater. This article discusses how that investigation inspired the authors to develop a stream-lined evaluation method for PGA's volatile organic compounds (VOCs), the process for establishing VOC cleanup levels, and the $26 million of remediation work needed to be done at the site. The heart of this effort is a computer program called VLEACH, loosely standing for VOC-LEACHing, which anticipates the influence of VOCs on PGA's groundwater, even as remediation proceeds.     

Evaluation of the effectiveness of traffic calming measures on vehicle speeds and pedestrian injury severity in Ghana

Objectives: Each year, pedestrian injuries constitute over 40% of all road casualty deaths and up to 60% of all urban road casualty deaths in Ghana. This is as a result of the overwhelming dependence on walking as a mode of transport in an environment where there are high vehicular speeds and inadequate pedestrian facilities. The objectives of this research were to establish the (1) impact of traffic calming measures on vehicle speeds and (2) association between traffic calming measures and pedestrian injury severity in built-up areas in Ghana.

Method: Vehicle speeds were unobtrusively measured in 38 selected settlements, including 19 with traffic calming schemes and 19 without. The study design used in this research was a matched case–control. A regression analysis compared case and control casualties using a conditional logistic regression.

Results: Generally, the mean vehicle speeds and the proportion of vehicles exceeding the 50?km/h speed limit were significantly lower in settlements that have traffic calming measures compared to towns without any traffic calming measures. Additionally, the proportion of motorists who exceeded the speed limit was 30% or less in settlements that have traffic calming devices and the proportion who exceeded the speed limit was 60% or more in towns without any traffic calming measures. The odds of pedestrian fatality was significantly higher in settlements that have no traffic calming devices compared to those that have (odds ratio [OR]?=?1.98; 95% confidence interval, 1.09–4.43). The protective effects of a traffic calming scheme that has a speed table was notably higher than those where there were no speed tables.

Conclusion: It was clearly evident that traffic calming devices reduce vehicular speeds and, thus, the incidence and severity of pedestrian injuries in built-up areas in Ghana. However, the fact that they are deployed on arterial roads is increasingly becoming a road safety concern. Given the emerging safety challenges associated with speed calming measures, we recommend that their use be restricted to residential streets but not on arterial roads. Long-term solutions for improving pedestrian safety proposed herein include bypassing settlements along the highways to reduce pedestrians’ exposure to traffic collisions and adopting a modern way of enforcement such as evidence-based laser monitoring in conjunction with a punishment regime that utilizes the demerit points system.