The more productive the engine, the higher the requirements for wear resistance to the contact pairs like the valve-guide system. The objective of the present research is to assess the thermo-mechanical influence of spiral-channel valve guides on stress redistribution and comparative wear resistance in the valve-guide interface. The research used a Brodix 10X cylinder head of the high-performance "Small-Block" V8 by Chevrolet (General Motors). The valve, manufactured from the Ti-6Al-4 V titanium alloy ([Formula: see text] MPa), and the guide of Bronze C86300 interact at high temperatures (900 °C at the valve head surface) and are cooled with an oil layer. Additional spiral channels on the guide surface proposed by the authors reduce the maximum and average von Mises stresses [Formula: see text] and [Formula: see text] by 17.96% and 10.42% (15.35 MPa and 1.29 MPa, respectively). In the numerical model, the expected influence of the spiral channels on heat transfer and lubrication was represented by an increased convection coefficient (up to 900 W/m²·°C) and a reduced effective friction coefficient (down to 0.05). Finite-element analysis was used to quantify thermo-mechanical stresses, while analytical modelling provided first-order estimates of how spiral channels modify lubrication and heat-transfer conditions inside the guide. Due to the reduction of [Formula: see text], the guide with spiral channels demonstrates a markedly improved fatigue response. The ANSYS Fatigue Tool indicated a substantially improved model-predicted fatigue response, with the comparative fatigue indicator exceeding that of the smooth guide by more than seven times. These results demonstrate the expediency of using spiral channels and motivates further research on optimizing their geometry and lubrication conditions. Such stress-reduction and wear-improvement mechanisms may be relevant for high-performance engines, motor sport applications and heavy-duty IC engines where valve-train durability is a limiting factor.
Aggregation-sex pheromones, that attract both sexes, are produced by male cerambycid beetles (Coleoptera: Cerambycidae) of the subfamilies Cerambycinae, Lamiinae, and Spondylidinae. Here, we present the results of a field experiment conducted at multiple sites in southern Texas, primarily near the border with the state of Tamaulipas, Mexico. At each site, we deployed traps baited with a 6-component blend of known pheromones of cerambycine and lamiine species + an ethanol lure, a 5-component blend of lamiine pheromones + an ethanol lure, an ethanol lure alone, and a solvent control. Over a ~3-wk period, 846 beetles of 51 species were trapped, representing 36 cerambycine, 14 lamiine, and one prionine species, and one species in the closely related family Disteniidae. For species collected from at least 5 study sites, nonparametric tests of treatment effects revealed that the generic 6-component blend + ethanol attracted significant numbers of one cerambycine species, while the lamiine blend + ethanol attracted one cerambycine species and 2 lamiine species. The ethanol lure attracted 2 additional cerambycine species in significant numbers. For species that were captured at fewer sites, chi-square goodness-of-fit tests showed that the 2 pheromone blends + ethanol attracted significant numbers of another 6 species of cerambycines and 4 species of lamiines. Captures noteworthy from the standpoint of collection records include the rare species Leptostylopsis lutea Dillon, and Lochmaeocles cornuticeps cornuticeps (Schaeffer) and Thryallis undatus (Chevrolet), 2 species which have rarely been reported outside Sabal Palm Sanctuary in Cameron County, Texas.
Almost half of the global population relies on non-sewered sanitation, wherein wastewater is treated directly at source or stored onsite and transported by road to treatment facilities (i.e., fecal sludge management). For the protection of public health and environmental ecosystems, efficient non-sewered sanitation systems are needed, in particular in urban areas where infrastructure lags behind rapid urbanization. Wastewater delivered to treatment plants in non-sewered areas has highly variable characteristics, as it arrives in batches from variable infrastructure. Established systems to handle this variability are often land- or energy-intensive, while operation of low-footprint alternatives strongly depends on the wastewater characteristics, making them difficult to implement for highly variable wastewater. The use of sensors could improve process control and increase the robustness of treatment technologies, while reducing the required footprint. However, there are no studies comparing the effectiveness of different sensor methods to measure solids in non-sewered wastewater. We therefore chose six sensors for predicting solids in wastewater and evaluated their performance in variable wastewater with a range of solids content, inorganic particles, salts, and fats. This work demonstrated that the sensors were affected differently by the variable wastewater. Micro-wave and Coriolis-flow technologies were strongly impacted by the addition of fat, oil, and grease as well as salts and inorganics, whereas optical sensors were mostly affected by inorganics, with optical light-attenuation having the lowest overall error, making it the best option for variable wastewater. A low-cost optical light-attenuation sensor had similar accuracy as a more expensive one when the solids content was low, indicating its value for inexpensive monitoring of effluent solids in decentralized settings. Additionally, three sensors were applied for process control of chemically enhanced dewatering with conditioners and geotextiles. Controlling conditioner dosing with sensors in the flocculation tank improved performance with 77% solids reduction, which is in the range of the alternative, time-intensive jar-test method (83% reduction). This study reveals that sensors can be useful in non-sewered wastewater management when the type of input wastewater is accounted for and that even low-cost sensors (<100 USD) can be suitable for many applications.
Advancing Health Literacy Franklin County was initiated in June 2021 with a goal of building a sustainable health literate community in Franklin County, Ohio, USA. The project was a collaboration among public health departments, health care organizations, an academic institution, and community organizations and included capacity-building over a 2-year period. Project evaluation included social network analysis mapping of organizational relationships over two project time periods to document change in this area. This brief report describes the social network analysis mapping as a project outcome, a valuable approach to advancing organizational health literacy and health equity, and a practical tool for other health literacy projects as sustainable relationships and networks are important in health literacy research and practice. [HLRP: Health Literacy Research and Practice. 2025;9(3):e78-e82.].
The initial frontal NCAP tests in 1979 included lap-shoulder belted driver and right-front passenger and lap belted 6-year-old (yo) in the rear. The 35 mph barrier tests were reviewed and analyzed for the restraint performance of the front occupants and child in the rear. The initial 100 crash tests (#1-#100) in the NHTSA database were searched for frontal barrier impacts. Fifteen tests met the criteria. There were three tests with the 1980 Chevrolet Citation at 35, 40 and 48 mph. There were 12 other tests with different passenger vehicles at 35 mph into the rigid barrier. The tests included a lap-shoulder belted Hybrid II (Part 572) dummy in the driver and right-front passenger seat and a lap belted 6 yo child dummy (Alderson VIP 6 C) in the center or right rear seat. Vehicle dynamics and occupant kinematics were analyzed, and dummy responses were compared. Vehicle deformation was progressive with impact speed for the Citation tests, leading NHTSA to settle on a 35 mph NCAP speed. The thirteen 35 mph NCAP tests had an average driver HIC of 1099 ± 381 (95th CI 207) and 3 ms chest acceleration of 55.7 ± 16.1 g (95th CI 8.8) with 7 of 13 vehicles failing FMVSS 208 injury criteria. The average right-front passenger HIC was 1179 ± 555 (95th CI 302) and 3 ms chest acceleration was 47.2 ± 14.6 g (95th CI 7.9) with 7 of 13 failing injury criteria. Only four tests (30.8%) passed driver and right-front passenger injury criteria.The responses in the rear seat were significantly worse. The average HIC was 2711 ± 1111 (95th CI 604) and 3 ms chest acceleration was 62.8 ± 10.6 g (95th CI 5.8). The films showed the child's upper body moved forward and rotated downward around the lap belt resulting in severe head impacts on the front seatback, floor, dummy legs or interior. All vehicles failed injury criteria by large margins. Submarining the lap belt was noted in 6 tests. HIC for the rear child was 2.47-times greater than the driver (t = 4.72, p < 0.001) and 2.30-times greater than the right-front passenger (t = 3.64, p < 0.005). In the 1979 NCAP tests, the child dummy experienced inadequate restraint by the lap belt in the rear seat. The child jackknifed around the lap belt, often submarined, with a severe head impact. No publication of the results has been found. NHTSA did not advise the public of the extremely poor restraint performance, even during the public discussions on the 1986 NTSB recommendation that U.S. vehicle manufacturers install lap-shoulder belts in rear outboard seats. None of the subsequent NCAP tests included a child or adult in the rear until nearly 25 years later.
Electronic Control Units (ECUs) have been increasingly used in modern vehicles to control the operations of the vehicle, improve driving comfort, and safety. For the operation of the vehicle, these ECUs communicate using a Controller Area Network (CAN) protocol that has many security vulnerabilities. According to the report of Upstream 2022, more than 900 automotive cybersecurity incidents were reported in 2021 only. In addition to developing a more secure CAN protocol, intrusion detection can provide a path to mitigate cyberattacks on the vehicle. This paper proposes a machine learning-based intrusion detection system (IDS) using a Support Vector Machine (SVM), Decision Tree (DT), and K-Nearest Neighbor (KNN) and investigates the effectiveness of the IDS using multiple real-world datasets. The novelty of our developed IDS is that it has been trained and tested on multiple vehicular datasets (Kia Soul and a Chevrolet Spark) to detect and classify intrusion. Our IDS has achieved accuracy up to 99.9% with a high true positive and a low false negative rate. Finally, the comparison of our performance evaluation outcomes demonstrates that the proposed IDS outperforms the existing works in terms of its liability and efficiency to detect cyber-attacks with a minimal error rate.
This perspectives article shares insights from a county-level project in Franklin County, Ohio, to build collective organizational health literacy (HL) capacity across new sustainable networks to advance community-level HL. We provide an overview of the initiative followed by specific insights from a cultural liaison, the article's first author, who works in a community-based organization. He shares his collectivist perspective in building HL capacity at the grassroots level toward community-level goals. A shift in focus from individual responsibility to collective impact represents an important mindset change for attaining HL and builds on community strengths and values toward health equity.
Size, morphology, and microstructure of particles emitted from one light-duty passenger vehicle (Buick Century; model year 1990; PM (particulate matter) mass emission rate 3.1 mg/km) and two light-duty trucks (Chevrolet C2; model year 1973; PM mass emission rate 282 mg/km, and Chevrolet El Camino; model year 1976; PM mass emission rate 31 mg/km), running California's unified driving cycles (UDC) on a chassis dynamometer, were studied using scanning electron microscopy (SEM). SEM images yielded particle properties including three-dimensional density fractal dimensions, monomer and agglomerate number size distributions, and three different shape descriptors, namely aspect ratio, root form factor, and roundness. The density fractal dimension of the particles was between 1.7 and 1.78, while the number size distribution of the particles placed the majority of the particles in the accumulation mode (0.1-0.3 microm). The shape descriptors were found to decrease with increasing particle size. Partial melting of particles, a rare and previously unreported phenomenon, was observed upon exposure of particles emitted during phase 2 of the UDC to the low accelerating voltage electron beam of the SEM. The rate of melting was quantified for individual particles, establishing a near linear relationship between the melting rate and the organic carbon 1 to elemental carbon ratio.
The objective of this study was to reconstruct 4 real-world motor vehicle crashes (MVCs), 2 with lumbar vertebral fractures and 2 without vertebral fractures in order to elucidate the MVC and/or restraint variables that increase this injury risk. A finite element (FE) simplified vehicle model (SVM) was used in conjunction with a previously developed semi-automated tuning method to arrive at 4 SVMs that were tuned to mimic frontal crash responses of a 2006 Chevrolet Cobalt, 2012 Ford Escape, 2007 Hummer H3, and 2002 Chevrolet Cavalier. Real-world crashes in the first 2 vehicles resulted in lumbar vertebrae fractures, whereas the latter 2 did not. Once each SVM was tuned to its corresponding vehicle, the Total HUman Model for Safety (THUMS) v4.01 was positioned in 120 precrash configurations in each SVM by varying 5 parameters using a Latin hypercube design (LHD) of experiments: seat track position, seatback angle, steering column angle, steering column telescoping position, and d-ring height. For each case, the event data recorder (EDR) crash pulse was used to apply kinematic boundary conditions to the model. By analyzing cross-sectional vertebral loads, vertebral bending moments, and maximum principal strain and stress in both cortical and trabecular bone, injury metric response as a function of posture and restraint parameters was computed. Tuning the SVM to specific vehicle models produced close matches between the simulated and experimental crash test responses for head, T6, and pelvis resultant acceleration; left and right femur loads; and shoulder and lap belt loads. Though vertebral load in the THUMS simulations was highly similar between injury cases and noninjury cases, the amount of bending moment was much higher for the injury cases. Seatback angle had a large effect on the maximum compressive load and bending moment in the lumbar spine, indicating the upward tilt of the seat pan in conjunction with precrash positioning may increase the likelihood of suffering lumbar injury even in frontal, planar MVCs. In conclusion, precrash positioning has a large effect on lumbar injury metrics. The lack of lumbar injury criteria in regulatory crash tests may have led to inadvertent design of seat pans that work to apply axial force to the spinal column during frontal crashes.
As the primary interface with the human body during rear impact, the automotive seat holds great promise for mitigation of Whiplash Associated Disorders (WAD). Recent research has chronicled the potential influence of both seat geometrical and constitutive properties on occupant dynamics and injury potential. Geometrical elements such as reduced head to head restraint, rearward offset, and increased head restraint height have shown strong correlation with reductions in occupant kinematics. The stiffness and energy absorption of both the seating foam and the seat infrastructure are also influential on occupant motion; however, the trends in injury mitigation are not as clear as for the geometrical properties. It is of interest to determine whether, for a given seat frame and infrastructure, the properties of the seating foam alone can be tailored to mitigate WAD potential. Rear impact testing was conducted using three model year 2000 automotive seats (Chevrolet Camaro, Chevrolet S-10 pickup, and Pontiac Grand Prix), using the BioRID P3 anthropometric rear impact dummy. Each seat was distinct in construction and geometry. Each seat back was tested with various foams (i.e., standard, viscoelastic, low or high density). Seat geometries and infrastructures were constant so that the influence of the seating foams on occupant dynamics could be isolated. Three tests were conducted on each foam combination for a given seat (total of 102 tests), with a nominal impact severity of Delta V = 11 km/h (nominal duration of 100 msec). The seats were compared across a host of occupant kinematic variables most likely to be associated with WAD causation. No significant differences (p < 0.05) were found between seat back foams for tests within any given seat. However, seat comparisons yielded several significant differences (p < 0.05). The Camaro seat was found to result in several significantly different occupant kinematic variables when compared to the other seats. No significant differences were found between the Grand Prix and S-10 seats. Seat geometrical characteristics obtained from the Head Restraint Measuring Device (HRMD) showed good correlation with several occupant variables. It appears that for these seats and foams the head-to-head restraint horizontal and vertical distances are overwhelmingly more influential on occupant kinematics and WAD potential than the local foam properties within a given seat.
One purpose of integrating voice interfaces into embedded vehicle systems is to reduce drivers' visual and manual distractions with 'infotainment' technologies. However, there is scant research on actual benefits in production vehicles or how different interface designs affect attentional demands. Driving performance, visual engagement, and indices of workload (heart rate, skin conductance, subjective ratings) were assessed in 80 drivers randomly assigned to drive a 2013 Chevrolet Equinox or Volvo XC60. The Chevrolet MyLink system allowed completing tasks with one voice command, while the Volvo Sensus required multiple commands to navigate the menu structure. When calling a phone contact, both voice systems reduced visual demand relative to the visual-manual interfaces, with reductions for drivers in the Equinox being greater. The Equinox 'one-shot' voice command showed advantages during contact calling but had significantly higher error rates than Sensus during destination address entry. For both secondary tasks, neither voice interface entirely eliminated visual demand. Practitioner Summary: The findings reinforce the observation that most, if not all, automotive auditory-vocal interfaces are multi-modal interfaces in which the full range of potential demands (auditory, vocal, visual, manipulative, cognitive, tactile, etc.) need to be considered in developing optimal implementations and evaluating drivers' interaction with the systems. Social Media: In-vehicle voice-interfaces can reduce visual demand but do not eliminate it and all types of demand need to be taken into account in a comprehensive evaluation.
Objective: Drivers' use of lane departure warning and prevention systems is lower than use of other crash avoidance technologies and varies significantly by manufacturer. One factor that may affect use is how well a system prevents unintended departures. The current study evaluated the performance of systems that assist in preventing departures by providing steering or braking input in a 2016 Chevrolet Malibu, 2016 Ford Fusion, 2016 Honda Accord, and 2018 Volvo S90. These vehicles were selected because a prior observational study found that the percentage of privately owned vehicles that had lane departure prevention systems turned on varied among these 4 automakers. Method: In each vehicle, a test driver induced 40 lane drifts on left and right curves by steering the vehicle straight into the curve so that vehicles departed in the opposite direction and 40 lane drifts on straightaways by slight steering input to direct the vehicle to left and right lane markers. Results: Vehicles from automakers with higher observed lane departure prevention use rates (Volvo, Chevrolet) featured systems that provided steering input earlier and more often avoided crossing lane markers by more than 35 cm compared to vehicles from automakers with lower observed use rates (Ford, Honda). Conclusion: The study identified functional characteristics (i.e., timing of steering input, prevention of departures more than 35 cm) of lane departure prevention systems that were strongly associated with observed activation of these systems in privately owned vehicles. Although this relationship does not imply causation, the findings support the hypothesis that functional characteristics of lane departure prevention systems affect their use. Designers may be able to use these results to maximize driver acceptance of future implementations of lane departure prevention.
The taxonomy of Bolivian, Brazilian and Paraguayan water beetles in the genus Hydrochus Leach, 1817 is presented. The known fauna now consists of 77 species, 37 of which are described as new species. The new species are diagnosed, and high-resolution images of the habitus and male genitalia of each species are given, as are distribution maps. The following new species of Hydrochus are described: H. accinctus n. sp., H. amazonicus n. sp., H. ampliarmus n. sp., H. argutulus n. sp., H. artus n. sp., H. austrinus n. sp., H. canalis n. sp., H. casuarius n. sp., H. clandestinus n. sp., H. colossus n. sp., H. compactus n. sp., H. constrictus n. sp., H. curvus n. sp., H. diffusus n. sp., H. distinctulus n. sp., H. distinctus n. sp., H. diversus n. sp., H. forcipuloides n. sp., H. forcipulus n. sp., H. fritillus n. sp., H. irregularis n. sp., H. liquidus n. sp., H. longissimus n. sp., H. membraneus n. sp., H. personatus n. sp., H. potenspiculatus n. sp., H. pronotulus n. sp., H. quinarius n. sp., H. rectus n. sp., H. reticulatus n. sp., H. robustus n. sp., H. sculptissimus n. sp., H. triangularis n. sp., H. trituberculatus n. sp., H. usualis n. sp., H. velatus n. sp., H. xingu n. sp. New locality data are provided for the following species: H. alternatus Perkins, H. argutus Knisch, H. astrictus Perkins, H. baloghi Makhan, H. basilaris Perkins, H. bicarinatus Perkins, H. bisinuatus Perkins, H. bituberculatus Perkins, H. choennii Makhan, H. coeneni Makhan, H. collaris Perkins, H. cracentis Perkins, H. denarius Perkins, H. drakei Knisch, H. drechseli Makhan, H. ducalis Knisch, H. elsjeae Makhan, H. formosus Perkins, H. hellmani Perkins, H. iduae Makhan, H. jenniferiduae Makhan, H. kellymilleri Perkins, H. leei Perkins, H. lobatus Perkins, H. lobissimus Perkins, H. merkli Makhan, H. obscurus Sharp, H. pietersenae Makhan, H. piroei Makhan, H. pumilio Knisch, H. pupillus Orchymont, H. purpureus Knisch, H. radhakishunae Makhan, H. richteri Bruch, H. secretus Knisch, H. shorti Perkins, H. soekhnandanae Makhan, H. spanglerorum Perkins, H. tarsalis Chevrolet, H. variabilis Knisch, H. zicsii Makhan.
Voice interfaces reduce visual demand compared with visual-manual interfaces, but the extent depends on design. This study compared visual demand during baseline driving with driving while using voice or manual inputs to place calls with Chevrolet MyLink, Volvo Sensus, or a smartphone. Mean glance duration and total eyes-off-road-time increased when using manual input compared with baseline driving; only eyes off road time increased with voice input. Confusion matrices developed with hidden Markov modelling characterise the similarity of glance sequences during baseline driving and while making phone calls. Glance sequences with the MyLink voice interface were misclassified as baseline driving more frequently than the other voice interfaces. Conversely, glance sequences with the Sensus and smartphone voice interfaces were more often misclassified as manual phone calling. Thus, the MyLink voice interface not only reduced the overall visual demand of placing calls, but produced glance patterns more similar to driving without another task. Practitioner Summary: The attention map and confusion matrix methodologies provide ways of characterising similarities and differences in glance behaviour across secondary task conditions, complementing traditional temporally based metrics (e.g. mean glance duration, long duration glances) while addressing some of the limitations of total-eyes-off-road-time (TEORT) for comparing secondary task behaviour to baseline driving.
Nearly one million compact pickup trucks were sold last year in the US. Manufacturers now produce extended-cab models of pickups such as the Ford Ranger, Chevrolet S-10, Dodge Dakota, and Toyota Tacoma that can accommodate at least two rear-seated passengers, making them attractive to families with children. However, the safety of these rear seats for children has not been determined. This Issue Brief summarizes a new study that examines and quantifies the risk of injury to children riding in compact pickup trucks. Based on these findings, parents should be advised against using these vehicles as family transportation.
We characterize regionally specific life cycle CO2 emissions per mile traveled for plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs) across the United States under alternative assumptions for regional electricity emission factors, regional boundaries, and charging schemes. We find that estimates based on marginal vs average grid emission factors differ by as much as 50% (using National Electricity Reliability Commission (NERC) regional boundaries). Use of state boundaries versus NERC region boundaries results in estimates that differ by as much as 120% for the same location (using average emission factors). We argue that consumption-based marginal emission factors are conceptually appropriate for evaluating the emissions implications of policies that increase electric vehicle sales or use in a region. We also examine generation-based marginal emission factors to assess robustness. Using these two estimates of NERC region marginal emission factors, we find the following: (1) delayed charging (i.e., starting at midnight) leads to higher emissions in most cases due largely to increased coal in the marginal generation mix at night; (2) the Chevrolet Volt has higher expected life cycle emissions than the Toyota Prius hybrid electric vehicle (the most efficient U.S. gasoline vehicle) across the U.S. in nearly all scenarios; (3) the Nissan Leaf BEV has lower life cycle emissions than the Prius in the western U.S. and in Texas, but the Prius has lower emissions in the northern Midwest regardless of assumed charging scheme and marginal emissions estimation method; (4) in other regions the lowest emitting vehicle depends on charge timing and emission factor estimation assumptions.
Research into secondary recovery of rare earth elements (REE) has focused mostly on hard disk drives and automotive applications. While REE content in Japanese and European vehicles is relatively well-known, understanding of U.S. vehicles is mostly based on database analysis. An attempt to pinpoint which components contain the most REEs was conducted on four different vehicle models including the Ford F-150, Chevrolet Silverado, Toyota Corolla and Honda Accord. The disassembly data were combined with 2017 vehicles in operation to estimate stocks and flows of Neodymium-Iron-Boron (NdFeB). Results showed that U.S. vehicles had major differences compared to Japanese and European vehicles. NdFeB magnets were only found in speakers ranging from 16 to 114 g/vehicle. An estimated 3.0-14 tonnes of NdFeB could be available from end-of-life vehicles in 2018 from different cohorts of the four aforementioned models. While opportunities for recycling NdFeB in vehicles exist, challenges are also present.
Most companies make charitable donations, but few approach their contributions with an eye toward enhancing their brands. Those that do take such an approach commit talent and know-how, not just dollars, to a pressing but carefully chosen social need and then tell the world about the cause and their service to it. Through the association, both the business and the cause benefit in ways they could not otherwise. Organizations such as Avon, ConAgra Foods, and Chevrolet have recognized that a sustained cause-branding program can improve their reputations, boost their employees' morale, strengthen relations with business partners, and drive sales. And the targeted causes receive far more money than they could have from direct corporate gifts alone. The authors examine these best practices and offer four principles for building successful cause-branding programs. First, they say, a company should select a cause that advances its corporate goals. That is, unless the competitive logic for supporting the cause is clear, a company shouldn't even consider putting its finite resources behind it. Second, a business should commit to a cause before picking its charitable partners. Otherwise, a cause-branding program may become too dependent on its partners. Third, a company should put all its assets to work, especially its employees. It should leverage the professional skills of its workers as well as its other assets such as distribution networks. And fourth, a company should promote its philanthropic initiatives through every possible channel. In addition to using the media, it should communicate its efforts through the Web, annual reports, direct mail, and so on. Cause branding is a way to turn the obligations of corporate citizenship into a valuable asset. When the cause is well chosen, the commitment genuine, and the program well executed, the cause helps the company, and the company helps the cause.
Vehicle technologies that increase seat belt use can save thousands of lives each year. Kidd, Singer, Huey, and Kerfoot (2018) found that a gearshift interlock was more effective for increasing seat belt use than an intermittent audible reminder, but interlocks may not be more effective than persistent audible reminders lasting at least 90 seconds. Forty-nine part-time belt users with a recent seat belt citation who self-reported not always using a seat belt drove two vehicles for 1 week each. Thirty-three drove a Chevrolet with an intermittent audible reminder followed by either a BMW with a persistent 90-second audible reminder (n = 17) or a Subaru with an incessant audible reminder (n = 16). The other 16 participants experienced the BMW persistent reminder followed by an interlock that limited speed to 15 mph during unbelted driving. These data were combined with data from 32 part-time belt users in Kidd et al. (2018) who experienced the intermittent reminder for 2 weeks or the intermittent reminder for 1 week and a gearshift interlock the next. Relative to the intermittent reminder, seat belt use was significantly increased an estimated 30% by the BMW persistent reminder, 34% by the Subaru incessant reminder, and 33% by the speed-limiting interlock. Belt use was increased an estimated 16% by the gearshift interlock, but this change was not significant. More participants circumvented the speed-limiting interlock to drive unbelted than the audible reminders. Responses to a poststudy survey indicated that interlocks were less acceptable than reminders. Audible reminders lasting at least 90 seconds and a speed-limiting interlock were more effective for increasing seat belt use than an intermittent audible reminder, but reminders were found more acceptable. Practical applications: Strengthening existing U.S. safety standards to require audible reminders lasting at least 90 seconds for front-row occupants could save up to 1,489 lives annually.
Despite their prevalence in the environment, and the myriad studies that have shown associations between morbidity or mortality with proximity to roadways (proxy for motor vehicle exposures), relatively little is known about the toxicity of gasoline engine emissions (GEE). We review the studies conducted on GEE to date, and summarize the findings from each of these studies. While there have been several studies, most of the studies were conducted prior to 1980 and thus were not conducted with contemporary engines, fuels, and driving cycles. In addition, many of the biological assays conducted during those studies did not include many of the assays that are conducted on contemporary inhalation exposures to air pollutants, including cardiovascular responses and others. None of the exposures from these earlier studies were characterized at the level of detail that would be considered adequate today. A recent GEE study was conducted as part of the National Environmental Respiratory Center (www.nercenter.org). In this study several in-use mid-mileage General Motors (Chevrolet S-10) vehicles were purchased and utilized for inhalation exposures. An exposure protocol was developed where engines were operated with a repeating California Unified Driving Cycle with one cold start per day. Two separate engines were used to provide two cold starts over a 6-h inhalation period. The exposure atmospheres were characterized in detail, including detailed chemical and physical analysis of the gas, vapor, and particle phase. Multiple rodent biological models were studied, including general toxicity and inflammation (e.g., serum chemistry, lung lavage cell counts/differentials, cytokine/chemokine analysis, histopathology), asthma (adult and in utero exposures with pulmonary function and biochemical analysis), cardiovascular effects (biochemical and electrocardiograph changes in susceptible rodent models), and susceptibility to infection (Pseudomonas bacteria challenge). GEE resulted in significant biological effects for upregulation of MIP-2, clearance of Pseudomonas bacteria, development of allergic response after in utero exposure, and cardiovascular indicators of vasoconstriction, oxidant stress, and damage.