High Mileage Research Articles

Prevalence and factors associated with asymptomatic Achilles tendon pathology in male distance runners

ObjectivesThis study investigated the prevalence of tendon pathology and associated factors in experienced, high mileage male endurance runners with no history of Achilles tendon pain. DesignCross-sectional study. SettingAchilles tendinopathy is a debilitating running injury affecting 50% of distance runners over their lifetime. It is diagnosed through a clinical examination and imaging, usually grey scale ultrasound (US) imaging. US imaging studies have shown that pathological changes can occur in asymptomatic individuals with no tendon pain. ParticipantsThirty seven male runners who had never had Achilles tendon pain. Main outcome measuresParticipants completed a running history survey, had their height, body mass, waist circumference, and ankle dorsiflexion range of movement (ROM) measured, and their tendons were assessed (normal, abnormal) using US imaging. ResultsAlmost half (46%) of these asymptomatic distance runners had at least one abnormal tendon. The runners with tendon pathology had significantly (p = 0.024) more years of running training (abnormal: median 20 years, interquartile range 6–25.5) than runners with no pathology (normal: median 7 years, interquartile range 5–15). No other significant differences between the groups were identified. ConclusionsAsymptomatic male distance runners had a high incidence of tendon pathology. Increased running years was associated with pathology in the Achilles tendon...

Differences in Lower Extremity Kinematic Variability between Healthy Runners Classified as Low or High Mileage

Evidence suggests that running mechanics may differ between runners based on their weekly mileage; greater weekly mileage (WM) may act as a protective mechanism against injury. While the interaction between coordination patterns and WM has been investigated, interaction between lower extremity (LE) kinematic variability and WM has not. PURPOSE: To compare changes in LE kinematic variability between low (LM) and high mileage (HM) healthy runners after a prolonged run. METHODS: 23 healthy participants (27.4±7.7 yrs., 1.70±0.11 m, 67.9±15.4 kg, 16.3±5.6 km/week) were included in the LM group, while 12 participants (25.1±6.3 years, 1.71±0.1 m, 65.8±9.4 kg, 46.9±14.5 km/week) were included in the HM group. Participants ran on a treadmill for 30 minutes at a self-selected training pace. 3D kinematic data were collected after 5 minutes of running and again at the end of run at 200Hz using reflective markers placed on the lower body with 6 infrared cameras. Variables of interest included ankle, knee and hip sagittal and frontal plane angles. Standard deviation (SD) and coefficient of variation (CV) were calculated for each dependent variable (DV) at the beginning and end of the run. Approximate entropy (ApEn) was also calculated for each DV at both time intervals. Two repeated measures ANOVAs with time and joint as the within-subject factors and group as the between-subject factor, were used to compare kinematic variability. Post-hoc analyses were conducted for significant interactions. Alpha level was set at 0.05. RESULTS: Average running speed for the LM and HM group were 2.5±.3 m/s and 2.9±.4 m/s, respectively. In the sagittal plane, a significant interaction was found between joint and group (F2,62=5.5, p=.006). Specifically, the HM group demonstrated greater amounts of variability (SD) than the LM group (LM=25.7±3.0; HM=29.5±3.7). No other statistically significant differences were attained. CONCLUSIONS: Kinematic variability differed between the LM and HM groups, but only for the knee in the sagittal plane. Ankle and hip sagittal plane movement was comparable between the LM and HM groups. This may suggest that movement of the ankle and the hip do not differ in response to having to control variability at the knee. When assessing kinematic variability, it is important to consider the weekly mileage of each runner.

Oiling the mileage gears

Given the chore of changing it every few months, the typical motorist realizes that engine oil degrades over time. Some will also notice the mysterious codes for the different grades—10W-40, 5W-30, and the like—or encounter terms such as “fully synthetic” or “high mileage” and conclude that not all oils are the same. What many drivers don’t realize is that oil does more than just help an engine run smoothly; it plays a crucial role in fuel economy. Coming up with new molecules and formulations that boost efficiency occupies most of the time of the chemists and engineers who work for lubricant and additive companies. And with automakers extracting as much mileage as they can from every drop of gasoline—a process that includes meeting new lubricant standards—now is a critical time for such efforts. Automakers are under constant pressure to make cars more fuel efficient. In 2012, the US Environmental Protection

Research on Subjective Rating Attenuation Analysis of Automobile NVH Characteristics

This paper explains the concept of high mileage automobile NVH(Noise Vibration and Harshness ) robustness. Based on the NVH characteristic subjective rating method, a quantitative analysis and evaluation method for NVH robustness of high mileage automobile is proposed. By using the subjective rating attenuation method of high mileage automobile NVH robustness and combine the actual parameters of three different types of cars, According to the calculation and analysis of the decline and attenuation of subjective rating attenuation method, the NVH robustness characteristics and change rules of three different types of cars at different mileage stages are obtained, which provides a reference for the NVH robustness analysis of high mileage automobile and the development of automobile NVH.

Real-world gaseous emissions of high-mileage taxi fleets in China

Mileage of taxi fleets is significantly higher than regular passenger vehicles in China, which might trigger greater tailpipe emissions of air pollutants. To investigate their real-world gaseous emissions, we applied portable emissions measurement systems (PEMSs) to test 44 gasoline and 24 bi-fuel taxis in seven cities. Our real-world measurement results indicated that a major part of the tested China 3 and China 4 gasoline taxis, especially the samples with high mileage (>300,000 km), far exceeded the corresponding emission limits of NOX, THC and CO. Only the newest China 5 gasoline taxis with relatively lower mileage had effective emission controls and the gaseous emissions were below the limits. Illegal tampering, malfunction and deterioration of three-way catalytic converters (TWC) are major reasons for high emissions from high-mileage taxis. First, China 4 gasoline taxis without TWC (purposely removed by drivers) increased their gaseous emissions than TWC-equipped counterparts by more than one order of magnitude. Second, bi-fuel taxis when using compress natural gas (CNG) had much higher NOX and THC emissions than those when using gasoline, which might be probably attributed to unsophisticated engine calibration and unfavorable TWC working conditions. Furthermore, TWC renewal could bring immediate and substantial emission reductions (up to 70%) for high-mileage taxis. However, such benefits from TWC renewal would become less significant as the mileage levels further increase. We also found a good correlation between CO and THC emissions for gasoline taxis, whose cold start effects were both significant. This study poses significant concerns regarding real-world emissions of high-mileage taxi fleets in China, which could consist of many gross emitters in the urban areas. Stringent in-use compliance programs and in particular frequent TWC renewals for high-mileage taxis should be implemented by policy makers in China.

Understanding high car use in relation to policy measures based on Swedish data

Globally, transport increases its share of emissions and the transport sector desperately needs an efficient climate policy including efficient strategies to reduce unsustainable levels of car use. By providing insights into the profile of passenger mileage by car in relation to levels estimated to be sustainable in 2050, this work gives insight into who will, and who needs to, be affected by policies and measures to achieve climate goals. The study, using Swedish national travel behaviour data, in line with international research, shows that a minority produces the majority of all passenger mileage by car. Adding an analysis of the national attitudinal study to the national travel behavioural data reveals that the high mileage producers further belong to groups with a low inclination to adopt sustainable behaviour, i.e. men, the middle aged and frequent car users. Policies and measures proposed to reduce unsustainable levels of car use need to be tailored to those groups in order to be efficient.

Impacts of State-Specific Policy and Legislation on Safety Advancement by Departments of Transportation

The overall goal of this research was to identify proven successful safety programs used in other states and assess the potential for safety improvement if similar programs were implemented in South Carolina. The research team not only sought out engineering solutions, but also expanded the search to include programs for enforcement, education, licensing, legal proceedings, and emergency services—therefore incorporating a wide range of stakeholder groups. South Carolina has, for many years, had one of the highest mileage death rates of any state in the nation—far exceeding the national fatality rate. While South Carolina Department of Transportation has a federal requirement to develop and maintain the Strategic Highway Safety Plan, which identifies the state’s key safety needs and guides investment decisions toward strategies and countermeasures with the most potential to save lives and prevent injuries, South Carolina legislation and state policies have effectively blocked many paths to safety improvements. Tree protection ordinances, limited policies for graduated drivers licensing, bans on camera enforcement, and lack of universal helmet laws continue to undermine efforts to improve motor vehicle safety in the state. Using a data-driven approach to safety program selection will yield support for changes in programs, policies, and standards, and have positive impacts on safety, operational, and economic aspects of the South Carolina roadway system. Further, the implementation of a data-driven safety management program will help to assure that the most appropriate strategies are implemented. The successful implementation of this research would likely result in a substantial reduction in loss of life and injuries associated with motor vehicle crashes in the state of South Carolina.

Consumer Valuation of Fuel Costs and Tax Policy: Evidence from the European Car Market

To what extent do car buyers undervalue future fuel costs, and what does this imply for tax policy? To address both questions, we show it is crucial to account for consumer mileage heterogeneity. We use product-level data for a panel of European countries and exploit fuel cost variation by engine. Despite a modest undervaluation of fuel costs, fuel taxes are more effective in reducing fuel usage than product taxes. They also perform better in terms of welfare, even when usage demand is held fixed. The reason is that fuel taxes better target high mileage consumers to purchase fuel efficient cars. (JEL D12, H25, H31, L62, L71)

The influence of exhaust system leak on the operating parameters of a turbocharged spark ignition engine

Turbocharging of an internal combustion engine is the most common technique to improve an engines’ performance. In present it is not hard to meet vehicles on the road with turbocharged SI engines, which have a high mileage, and because of this fact there is a high risk of exhaust systems leak. This might have its influence not only on the emissions, but also on the vehicles performance. Thereby this dissertation shows the comparative analysis of the influence of exhaust system leak in the catalyzer input on the exhaust gasses composition in the catalyzer output and the operation parameters of an turbocharged SI engine. During the research some parameters were recorded and compared, e. g.: the engines power and torque, the injec-tors opening time, the oxygen sensors voltage signals in the input and in the output of the catalyzer, the concentration of harmful gasses in the exhaust tailpipe. The research was conducted with the use of a single roller MAHA MSR 500 chassis dynamometer. A series of torque measurements was performed. Under these measurements a simulation of the exhaust system leakage of a turbocharged SI passenger car engine was made. As a result three variations of the wideband oxygen sensor acting were reached. The wideband sensor is mounted between the turbocharger unit and the input of the catalyzer. In the test the influence of the leakage on the injector’s opening time and the composition of harmful exhaust substances were pointed.

How Autonomous Driving May Affect the Value of Travel Time Savings for Commuting

Autonomous driving is being discussed as a promising solution for transportation-related issues and might bring some improvement for users of the system. For instance, especially high mileage commuters might compensate for some of their time spent traveling as they will be able to undertake other activities while going to work. At the same time, there are still many uncertainties and little empirical data on the impact of autonomous driving on mode choices. This study addresses the impact of autonomous driving on value of travel time savings (VTTS) and mode choices for commuting trips using stated-choice experiments. Two use cases were addressed – a privately owned, and a shared autonomous vehicle – compared with other modes of transportation. The collected data were analyzed by performing a mixed logit model. The results show that mode-related factors such as time elements, especially in-vehicle time and cost, play a crucial role for mode choices that include autonomous vehicles. The study provides empirical evidence that autonomous driving may lead to a reduction in VTTS for commuting trips. It was found that driving autonomously in a privately owned vehicle might reduce the VTTS by 31% compared with driving manually, and is perceived similarly to in-vehicle time in public transportation. Furthermore, riding in a shared autonomous vehicle is perceived 10% less negatively than driving manually. The study provides important insights into VTTS by autonomous driving for commuting trips and could be a base for future research to build upon.

Work Environment, Stress, and Driving Anger: A Structural Equation Model for Predicting Traffic Sanctions of Public Transport Drivers.

Public transport is an effective and sustainable alternative to private vehicle usage, also helping to reduce the environmental impact of driving. However, the work environment of public transport operators is full of adverse conditions, which, together with their high mileage, may increase the occurrence of negative safety outcomes such as traffic accidents, often preceded by risky road behaviors enhanced by stress, anger, and difficult operating conditions. The aims of this study were, first, to determine the association between work-related psychosocial factors and individual characteristics of public transport drivers and the rate of traffic sanctions they are subject to; and second, to assess the mediation of driving anger in this relationship. A sample of professional drivers (57.4% city bus, 17.6% taxi, and 25% inter-urban bus male operators) was used for this cross-sectional study, responding to a five-section survey including demographic data and driving-related factors, psychosocial work factors including job stress, driving stress, risk predisposition, and driving anger. The results of this study showed significant associations between work-related factors: measures of stress and self-reported rates of traffic fines. Second, it was found that driving anger mediates the associations between driving stress, risk predisposition, and traffic sanctions; and partially mediates the association between driving experience, hourly intensity, and job stress. This study supports the idea that traffic penalties reported by public transport rates are preceded by work-related, personality, and other individual factors that, when combined with driving anger, enhance the occurrence of road misbehavior that may affect overall road safety.

Quality of life of female and male vegetarian and vegan endurance runners compared to omnivores \u2013 results from the NURMI study (step 2)

BackgroundHealth-related effects of a vegetarian or vegan diet are known to support parameters positively affecting exercise performance in athletes, whereas knowledge about psyche and wellbeing is sparse. Therefore, the aim of the Nutrition and Running High Mileage (NURMI) Study (Step 2) was to compare Quality of Life (QOL) scores among endurance runners following a vegetarian or vegan diet against those who adhere to an omnivorous diet.MethodsThe study was conducted following a cross-sectional design. A total of 281 recreational runners (159 women, 122 men) completed the WHOQOL-BREF questionnaire consisting of the domains physical health, psychological wellbeing, social relationships and environment, which generates scores on a scale from 4 to 20. Data analysis was performed using ANOVA.ResultsIt was found that 123 subjects followed an omnivorous diet and 158 adhered to a vegetarian/vegan diet. There were 173 runners who met the inclusion criteria (‘NURMI-Runners’), among them 103 half-marathoners and 70 marathoners and ultramarathoners, as well as 108 10 km runners as control group. Overall QOL scores were high (~ 16.62 ± 1.91). Men had higher scores than women due to high scores in the physical health and psychological well-being dimensions. Adhering to an omnivorous diet affected environment scores for women and social relationships scores for men. A minor effect concerning race distance was observed in women, where half-marathoners had a higher environmental score than 10-km runners. A moderate diet×race distance interaction on environment scores was shown for men.ConclusionsThe results revealed that endurance runners had a high QOL regardless of the race distance or diet choice. These findings support the notion that adhering to a vegetarian or vegan diet can be an appropriate and equal alternative to an omnivorous diet.Trial registrationISRCTN73074080. Registered 12th June 2015, retrospectively registered.

Investigating fuel dosage non-repeatability of low-pressure gas-phase injectors

The advancement of the means of transport, having its origins in the increasingly stringent exhaust emission limits, forces a better and more accurate fuel dosage to the engine. The increased computing power of the engine ECUs has led to a more precise analysis of the process. A problem arose of the adaptation of engines to LPG fueling. The uneven fuel dosage to the cylinders is partly adjusted by the injection timing. Therefore, in search for other reasons for engine inappropriate operation, the author decided to determine the cycle-by-cycle non-repeatability of fuel dosage of gas-phase injectors. To this end, an original research stand including all necessary equipment was applied. By recording the air pressure at the outlet of the nozzles of different injectors, individual cycles were analyzed. Based on the average pressure values in the cycles, the non-repeatability rate of the fuel dosage was determined. As a result of the performed research on randomly selected low-pressure gas-phase injectors, it was observed that brand new injectors have a non-repeatability rate of approx. 0.3%. For the injectors already in operation an approx. 36% non-repeatability rate was observed compared to the brand new ones. When comparing the brand new and the end-of-life (high mileage) injectors, a 1.5 times increment of the non-repeatability of the fuel dosage was determined. The determined parameter is significant because of the narrowing of the combustible mixture control window in modern engine control systems. As a result, this may lead to detecting errors when the fuel dosage repeatability is poor.

Brake System Performance at Higher Mileage

Brake System Performance at Higher Mileage

Risk factors for injury associated with low, moderate, and high mileage road marching in a U.S. Army infantry brigade

ObjectivesRoad marching is an important physical training activity that prepares soldiers for a common occupational task. Continued exploration of risk factors for road marching-related injuries is needed. This analysis has assessed the association between modifiable characteristics of physical training and injury risk. MethodsInjuries in the previous 6 months were captured by survey from 831 U.S. Army infantry soldiers. Road marching-related injuries were reported as those attributed to road marching on foot for specified distances while carrying equipment. Frequencies, means, and relative risk ratios (RR) for road marching-related injury with 95% confidence intervals (CI) were calculated. Adjusted odds ratios (OR) and 95% CI were calculated for leading risk factors using multivariable logistic regression. DesignRetrospective cohort study. ResultsHalf (50%) of reported injuries were attributed to road marching or running. When miles of exposure were considered, injury risk during road marching was higher than during running (RRroad marching/running=1.8, 95% CI: 1.38–2.37). A higher product of road marching distance and weight worn (pound-miles per month) resulted in greater injury risk (RR≥1473 pound-miles/<1472=1.92, 95% CI: 1.17–2.41). Road marching-related injuries were associated with carrying a load >25% of one’s body weight (OR>25%/1-20%=2.09, 95% CI: 1.08–4.05), having high occupational lifting demands (OR50-100+lbs/25-50lbs=3.43, 95% CI: 1.50–7.85), road marching ≥5 times per month (OR≥5 times/4 times=2.11, 95% CI: 1.14–3.91), and running <4 miles per week during personal physical training (OR0/≥10 miles/week=3.56, 95% CI: 1.49–8.54, OR1-4/≥10 miles/week=4.14, 95% CI: 1.85–9.25). ConclusionsIdeally, attempts should be made to decrease the percentage of body weight carried to reduce road marching-related injuries. Since this is not always operationally feasible, reducing the cumulative overloading from both physical training and occupational tasks may help prevent injury.

Do environmental rebates affect the replacement of durable products? An analysis of vehicle ownership duration in Japan

To reduce the environmental burden, many countries are providing consumers with rebates for the purchase of eco-friendly products. Although such rebate programs increase the market share of eco-friendly products and can mitigate environmental problems, they may distort the replacement cycle of durable products. The Japanese government implemented two series of eco-car rebate programs between 2009 and 2012. In this paper, we analyze the mileage of used vehicles and assess whether the rebate programs distorted the vehicle replacement cycle. Our duration analysis reveals that people sold the vehicle with low mileage in the first eco-car period but kept the vehicle with high mileage before the second eco-car period came into play.

Analysis of Ash in Low Mileage, Rapid Aged, and High Mileage Gasoline Exhaust Particle Filters

Analysis of Ash in Low Mileage, Rapid Aged, and High Mileage Gasoline Exhaust Particle Filters

Accuracy of young male drivers’ self-assessments of driving skill

Accurate self-assessment of skill is important because it creates an appropriate level of confidence and hence behaviour. Inaccurate self-assessment of driving ability has been linked to reckless driving and accidents. Inaccurate self-assessment of driving skills may be a contributing factor to the over-representation of young male drivers in accident statistics. Most previous research on self-assessment of driving skills did not compare self-reported skills to objectively measured driving skills, so the aims of this study were: (1) to test the accuracy of young male drivers’ self-assessments of specific driving skills by comparing them with performance in a driving simulator; (2) to test whether self-assessment accuracy varied with driving skill, driving experience and sensation-seeking propensity. We found that young male drivers’ self-assessments were inconsistent with their driving performance, and that this inconsistency varied with driving skill, driving experience and sensation-seeking propensity. Groups with particularly inaccurate self-assessments are at high risk, because of their relative lack of skill, high mileage and sensation-seeking propensity. Self-assessments of hazard prediction and detection skills were particularly inaccurate. Understanding self-assessments of driving skill is crucial, but further studies are needed to allow preventive policies and interventions to take factors affecting self-assessments into account.

Superlow friction of high mileage used oil with CuDTC in presence of MoDTC

PurposeThe purpose of this paper is to improve the antifriction and antiabrasive behavior of the used oil through the addition of a lubricant.Design/methodology/approachThe author selected 85W-90 used oil with three kinds of 4,758, 10,507 and 16,223 km mileages, which may represent run-in wear period, steady-state wear period and rapid wear for used oil, respectively. Nano copper, molybdenum dithiocarbamate (MoDTC) and copper dioctyl dithiocarbamate (CuDTC) of lubricant additive are added to the used oil to improve its antifriction performances and service life. The influence of lubricant additive on the tribological properties of used oil is investigated by the friction tests.FindingsAn abnormal phenomenon has been observed by the friction test under high mileage used oil with CuDTC in presence of MoDTC lubrication, and superlow friction coefficient of 0.04 has been achieved after a running-in period for the first time. It is found that CuDTC additive is beneficial to improve greatly the antifriction behavior of used oil, especially when MoDTC is present. The results indicate that the dissoluble of CuDTC and the tribochemical reaction of MoDTC play an important role in superlow friction of high mileage used oil. Moreover, the superlow friction is also closely related to the viscosity of used oil.Originality/valueThe possible mechanism of superlow friction is attributed to the additive thinning effect and the synergistic effect of the dissoluble of CuDTC and the tribochemical reaction of MoDTC binary lubricant additives in high mileage used oil. This work will extend the application of CuDTC additive widely and explore a new method to the reutilization and the life extension of used lubricating oil.

Expectation-Based Reference-Dependent Preferences: Evidence from the Used-Car Retail Market

This paper empirically tests the expectation-based reference-dependent preference theory, by exploiting a large panel of used-car daily listings from a leading automobile classified website. The unique features of the paper’s empirical strategy include: 1) it explicitly identifies consumers’ reference points as their expectations; 2) it uses a unique panel dataset on the non-negotiable daily listing prices for cars advertised by a large national dealership to pin down the prices that car buyers expected and the actual prices; and 3) its tests for loss aversion consider the problem that price changes may affect cars’ perceived quality or be correlated with the actual unobserved quality. The paper finds that — controlling for a car’s actual price, its detailed attributes, the competitive environment and a rich set of fixed effects — an unanticipated price increase (drop) significantly lowers (increases) the car’s daily sale probability; the estimated reference-price effects are weaker in the cases when consumers were less likely to recall the previous listing prices; and, although the magnitude of the average reference-price effect is significantly larger for price increases than for decreases, the asymmetry in the effects is statistically more significant for cars of older vintage or with higher mileage, suggesting that the asymmetry in the reference-price effects is driven partly by price decreases being bad news for cars’ unobserved quality.