Child Passenger Safety: Decisions about Seating Location, Airbag Exposure, and Restraint Use

The installation of passenger-side airbags in new vehicles complicates efforts to maximize child safety in motor vehicle crashes. It has been recommended by both public and private organizations that children sit in the rear seat with proper restraint to achieve maximum safety. Drivers now need to decide whether a child should be restrained, where the child should be seated (front versus rear), and whether the child should be seated in front of a passenger-side airbag. This research was undertaken to determine which choice minimizes the risk of fatality to children. Using data from the U.S. Fatality Analysis Reporting System for calendar years 1989 to 1998, fatal vehicle crashes with child passengers younger than 13 years were analyzed. The effectiveness of passenger-side airbags and rear seating for children, by age category and restraint use, was estimated using the double-pair comparison method. For each of four age categories, the fatality risk of each possible combination of restraint use, seating location, and airbag presence was also estimated using logistic regression. Passenger airbags were associated with an increase in child fatality risk of 31% for restrained children, and 84% for unrestrained children. Passenger airbags did appear to offer protection to restrained 9- to 12-year-old children. Restraint use and rear seating were associated with statistically significant reductions in the odds of a child dying in a crash. In order to minimize child fatality risk, parents should seat children in the rear of the vehicle while using the proper child restraint system, especially in vehicles with passenger airbags. These findings support current public education efforts in the United States.     

Is It Safer to Fly or Drive?

In attempts to soothe the nascent fear of the scheduled airline traveler, passengers waiting takeoff are sometimes reminded of the cliche that they may have already completed the most dangerous part of their trip — the drive to the airport. The objective of this paper is to communicate under what conditions air travel is indeed safer than highway travel and vice versa. The conventional wisdom among risk communicators that air travel is so much safer than car travel arises from the most widely quoted death rates per billion miles for each — 0.6 for air compared to 24 for road. There are three reasons why such an unqualified comparison of aggregated fatality rates is inappropriate. First, the airline rate is passenger fatalities per passenger mile, whereas the road rate is all fatalities (any occupants, pedestrians, etc.) per vehicle mile. Second, road travel that competes with air travel is on the rural interstate system, not on average roads. Third, driver and vehicle characteristics, and driver behavior, lead to car-driver risks that vary over a wide range. Expressions derived to compare risk for drivers with given characteristics to those on airline trips of given distance showed that 40-year-old, belted, alcohol-free drivers of cars 700 pounds heavier than average are slightly less likely to be killed in 600 miles of rural interstate driving than in airline trips of the same length. Compared to this driver, 18-year-old, unbelted, intoxicated, male drivers of cars 700 pounds lighter than average have a risk over 1000 times greater. Furthermore, it is shown that the cliche above is untrue for a group of drivers having the age distribution of airline passengers.     

Should Persons with Diabetes Be Licensed to Drive Trucks?—Risk Management

How should a regulatory agency interpret a risk analysis that concludes there is a small increase in risk? The agency must decide on behalf of society whether the increased risk is large enough to justify banning the risky activity or taking some other step to lessen the risks. In a companion paper (Songer et al.), we conclude that licensing insulin using persons to drive commercial motor vehicles in interstate commerce would result in 42 additional crashes each year. Here we address risk management issues by interpreting the number of additional crashes and the relative risks of the prospective handicapped drivers. Are the number of additional crashes (42) significant? Is the increase in the annual crash risk (from 0.00785 to 0.032 for non-insulin dependent and 0.048 for insulin dependent persons) significant? Are the relative risks significant for all insulin using drivers (4.7)? For drivers with a history of severe hypoglycemic reactions (19.8)? How should society tradeoff risk increases for increases in opportunity for these handicapped persons? We review other social decisions concerning highway safety: Accepting the increasing risks of letting 16 year olds drive, allowing extremely light cars, allowing some unsafe highways, and allowing extremely unsafe driving conditions at some times of day. We conclude that the additional risks from insulin using persons are well within the current accepted range of risks. Currently, 70% of states permit insulin using persons to drive trucks within their state. Nonetheless, the social cost, due to fatalities, injuries, and property damage from allowing a person with a history of severe hypoglycemic reactions to drive is more than $19,700 per year.     

Trait Predictors of Aggression and Crash‐Related Behaviors Across Drivers from the United Kingdom and the Irish Republic

Aggressive driving is acknowledged as a contributor to motor vehicle crashes. This study explored a theoretical model of aggressive expression and crash‐related outcomes using self‐report data collected, using an online questionnaire, from drivers in the United Kingdom and the Republic of Ireland. The proposed model tested whether the personality traits of boredom proneness, sensation seeking, and impulsivity, coupled with trait driving anger, predicted aggressive driving; and whether aggressive driving predicted crash‐related outcomes (loss of concentration and control, near misses, and moving violations). The structural model was confirmed, with aggressive expressions of anger being found to mediate the relationships driving anger and impulsivity had with the crash‐related outcomes. Multigroup invariance analysis showed that the model remained invariant across drivers from the United Kingdom and Ireland, suggesting that the contributing factors for aggressive expression and crash involvement are similar across both countries. When self‐reported crash‐related conditions were compared between drivers in the United Kingdom and Ireland, drivers in the United Kingdom reported more aggressive driving, more minor crashes, more incidents of road rage, and more frequent losses of concentration and vehicle control.     

服务质量、需求强度与共享出行平台定价——基于平台封闭与开放策略的视角

共享出行平台逐步由增加用户流量的扩张期进入提升出行多元化体验的稳定期,通过采取开放策略,平台在原有共享车基础上引入出租车来提供差异化服务。本文基于双边市场理论,构建共享出行平台定价策略模型,并利用计算实验方法,在Repast中模拟共享出行平台多智能体运行场景。研究发现：①无论平台选择封闭策略还是开放策略,平台对共享车收取的交易费应随着乘客出行需求强度增大而升高,且应随着共享车服务质量的增大而降低;平台对乘客收取的交易费应随着共享车服务质量增大而升高,且应随着乘客的出行强度的增大而降低。②平台开放程度越高,平台对共享车收取的交易费越低,对乘客收取的交易费越高。③为了利润最大化,平台应选择开放策略,并需注重提高共享车的服务质量。本文为共享出行平台优化运营策略提供了理论指导。     

Do Drivers of Small Cars Take Less Risk in Everyday Driving?

Previously reported observed data on risky everyday driving are brought together and reanalyzed in order to focus on the relation between risky driving and the size of the car being driven, as indicated by car mass. The measures of risky driving include separation between vehicles in heavy freeway traffic and speed on a two lane road. Observed seat belt use provides a third measure of driver risk. Confounding effects arising from the observed association between car mass and driver age are taken into account by segmenting the data into three driver age groups. Driver risk taking is found to increase with increasing car mass for each of these three aspects of everyday driving. The implications of these results with respect to driver fatality rates are discussed in terms of a simple model relating observed risky driving to the likelihood of involvement in a severe crash.     

Real-World Personal Conversations Using a Hands-Free Embedded Wireless Device While Driving: Effect on Airbag-Deployment Crash Rates

A wireless device embedded in the vehicle allowed the user to engage in a personal hands-free conversation (HFC), and automatically placed an emergency notification call to an OnStar call center if the vehicle was involved in a crash in which its airbag deployed. A database stored the exact counts, start timestamps, and billed durations of all HFC and airbag notification calls. In 30 months of naturalistic driving, there were 91 million HFC calls from an average of 323,994 drivers per month who made calls. There were 14 airbag deployments in 276 million driver-minutes of HFC conversation for an exposed incidence rate of 5.08 airbag crashes per 100 million driver-minutes. There were 2,023 airbag deployments in an estimated 24.7 billion driver-minutes of no HFC conversation for a not-exposed incidence rate of 8.18 airbag crashes per 100 million driver-minutes. The crash incidence rate ratio (IRR) is the ratio of these two rates or 0.62 (95% C.I. 0.37 to 1.05). Sensitivity analyses controlled for the impact on the crash IRR of estimated time spent driving per day and calls by passengers. Counting all crashes as much as 20 minutes later than a call as related to that call gave similar results. We conclude that for personal conversations using a hands-free embedded device the risk of an airbag crash is somewhere in a range from a moderately lower risk to a risk near that of driving without a recent personal conversation. These results are not consistent with the large increase in crash risk reported in epidemiological studies using the case-crossover method.     

The Risks of Licensing Persons with Diabetes to Drive Trucks

The 1990 Americans with Disabilities Act forbids employers to bar disabled persons from jobs unless employers can show the disabled person cannot perform the tasks. The Federal Highway Administration will not license persons with diabetes mellitus to drive commercial motor vehicles in interstate commerce. These individuals may experience severe hypoglycemia, greatly increasing their risk of losing control of the truck. This prohibition is currently being reexamined. We describe the disease process leading to severe hypoglycemia and its physical manifestations. To quantify the risks of licensing persons with diabetes to use insulin, we first estimate the number of potential insulin-using drivers. We estimate that 1420 insulin-using persons would seek licenses in the United States if they were permitted to do so (920 noninuslin dependent and 500 insulin dependent). Next, we estimate the annual incidence of mild and severe hypoglycemia in these populations. The third step is to estimate the number of hypoglycemic episodes while driving. Estimating the likelihood of a crash due to a mild or severe hypoglycemic episode is the fourth step. We estimate that an additional 42 crashes each year would occur if insulin using persons were licensed to drive commercial motor vehicles in interstate commerce (20 from insulin dependent and 22 from non-insulin dependent drivers).     

基于逆向供应的V2G市场电价策略研究

本文讨论了电动汽车普及后电力公司借助V2G技术建立V2G市场的市场运行模式,对电力公司在不同价格策略下,电动汽车保有者参与V2G市场向电力公司反向供电的响应度进行对比、分析.结果表明:电力公司采取分时电价策略时,可以以较不采用分时电价情景低的反向购电价格获得更高的V2G市场响应度,在不损失电动汽车保有者效益的情况下,使电力公司获得更高的总收益.     

同时集散货物的开放式车辆路径问题研究

本文研究了车辆工作时间限制下同时集散货物的多配送中心开放式车辆路径问题,以车辆数和运输里程最小为目标,建立了多目标规划模型,提出了基于拉格朗日松弛技术和禁忌搜索算法的混合求解算法。 该算法首先求出最优解的最大下界,然后采用客户点的分配和调整策略实现解的可行化,其中禁忌搜索引入了4种领域搜索方法,采用了随机变领域搜索方法和重起策略。算例分析表明,该算法能有效地找到满意解,且采用开放式安排路线比闭合式安排路线更加经济合理。     

Exposure to Traffic and Risk of Hospitalization Due to Injuries

Research on the risk of motor vehicle injuries and their relationship with the amount of travel has been only partially analyzed. The few individual exposure assessments are related to very specific subsets of the driving and traveling populations. This study analyzes the relationship between kilometers traveled and hospitalization due to motor vehicle injuries. Twelve thousand three hundred and sixty nine Spanish university graduates from the Seguimiento Universidad de Navarra multipurpose cohort study were evaluated. They had not been hospitalized due to motor vehicle injuries at baseline and were followed up to eight years. Biannual questionnaires allowed for self‐reporting of kilometers traveled in motor vehicles, together with incidence of hospitalization. Covariates in the Cox regression models included age and gender and baseline use of safety belt while driving, driving a vehicle with driver‐side airbag, driving a motorcycle, and drinking and driving. There were 49,766 participant‐years with an average yearly travel of 7,828 km per person‐year. Thirty‐six subjects reported a first hospitalization event during this time. The adjusted hazard ratio per additional kilometer traveled was 1.00005 (95% confidence interval 1.000013 to 1.000086). Even the smallest of reductions in the amount of kilometers traveled (from an average of 3,250 km per year to 1,000) has a statistically significant protective effect on the likelihood of sustaining hospitalization due to motor vehicle injury (aHR 0.9, 95% CI 0.78 to 0.98). In light of current policies aimed to reduce motorized traffic due to environmental concerns, it may be appropriate to consider the additional health benefit related to reductions in injuries.     

Tree‐Based Logistic Regression Approach for Work Zone Casualty Risk Assessment

This study presents a tree‐based logistic regression approach to assessing work zone casualty risk, which is defined as the probability of a vehicle occupant being killed or injured in a work zone crash. First, a decision tree approach is employed to determine the tree structure and interacting factors. Based on the Michigan M‐94\I‐94\I‐94BL\I‐94BR highway work zone crash data, an optimal tree comprising four leaf nodes is first determined and the interacting factors are found to be airbag, occupant identity (i.e., driver, passenger), and gender. The data are then split into four groups according to the tree structure. Finally, the logistic regression analysis is separately conducted for each group. The results show that the proposed approach outperforms the pure decision tree model because the former has the capability of examining the marginal effects of risk factors. Compared with the pure logistic regression method, the proposed approach avoids the variable interaction effects so that it significantly improves the prediction accuracy.     

基于复杂网络演化博弈的绿色消费者对新能源汽车扩散的影响研究

绿色消费行为是绿色产业发展的主要推动力。以市场需求侧与供给侧协调为思路,基于复杂网络演化博弈理论,构建新能源汽车扩散模型,研究绿色消费者对制造商微观决策与宏观新能源汽车扩散的影响。在小世界网络情境下进行仿真分析,结果表明：宏观上,绿色消费者溢价和绿色消费者比例的增加都能够促进新能源汽车扩散,但是二者的微观影响机制不同。绿色消费者溢价的增加总是使得演化稳定状态下所有制造商的平均收益都增加,而绿色消费者比例的增加可能导致所有制造商的平均收益都减少。在产业层面,绿色消费行为对新能源汽车扩散具有积极的促进作用,而在企业层面,绿色消费行为的作用并非总是积极的。因此,一方面,促进新能源汽车扩散需要加强对需求侧的重视。从扩大绿色消费者规模和提高绿色消费者溢价两方面考虑,政府应该通过制定激励机制或加大环保宣传等财税或非财税方式促使消费者环保意识的觉醒。另一方面,新能源汽车制造商应该制定恰当的营销策略促使绿色消费者对新能源汽车产生更多溢价;燃油汽车制造商能够从新能源汽车制造商的营销策略中搭便车,应避免与新能源汽车制造商进行恶性竞争。论文从影响因素和扩散机制两方面拓展了新能源汽车扩散理论研究体系,研究结论...     

Motor vehicle recalls: Trends,patterns and emerging issues

This paper examines patterns and trends in motor vehicle safety recalls using a dataset based on 23.1 million vehicles registered in the UK between 1992 and 2002. A safety recall occurs when vehicle manufacturers call vehicles that have been sold and are in use back to their dealerships for safety-related remedial work. Safety recalls can be a strategic concern for car makers, having the potential to damage brand value, reduce stock price as well as resulting in significant direct costs. The data from this study show that the incidence of vehicle recalls is increasing—between 1998 and 2002 there was an average of over 120 recall incidents per annum in the UK, compared to less than 50 per annum between 1992 and 1994. Total numbers of vehicles recalled show no clear trend over time, but the absolute level of recalls year on year is very high: in the UK, 10.8 million vehicles were recalled during 1992–2002, representing 47% of all vehicle UK registrations in the period. Moreover, there are substantial differences in recall rates between different car manufacturers, suggesting that recall rates may be a useful indicator of process performance in the automotive design-and-production value chain. European and American producers have recall rates that are nearly three times greater than their East Asian counterparts. This paper concludes with some ideas that may explain these patterns and suggests an agenda for further research.     

The Influence of Feelings While Driving Regular Cars on the Perception and Acceptance of Self‐Driving Cars

Self‐driving vehicles will affect the future of transportation, but factors that underlie perception and acceptance of self‐driving cars are yet unclear. Research on feelings as information and the affect heuristic has suggested that feelings are an important source of information, especially in situations of complexity and uncertainty. In this study (N = 1,484), we investigated how feelings related to traditional driving affect risk perception, benefit perception, and trust related to self‐driving cars as well as people's acceptance of the technology. Due to limited experiences with and knowledge of self‐driving cars, we expected that feelings related to a similar experience, namely, driving regular cars, would influence judgments of self‐driving cars. Our results support this assumption. While positive feelings of enjoyment predicted higher benefit perception and trust, negative affect predicted higher risk and higher benefit perception of self‐driving cars. Feelings of control were inversely related to risk and benefit perception, which is in line with research on the affect heuristic. Furthermore, negative affect was an important source of information for judgments of use and acceptance. Interest in using a self‐driving car was also predicted by lower risk perception, higher benefit perception, and higher levels of trust in the technology. Although people's individual experiences with advanced vehicle technologies and knowledge were associated with perceptions and acceptance, many simply have never been exposed to the technology and know little about it. In the absence of this experience or knowledge, all that is left is the knowledge, experience, and feelings they have related to regular driving.     

The Roads Ahead: Collision Risks, Trends, and Safety of Drivers

The propensity of fatal traffic collisions transcends driver age and reinforces the need to evaluate, among other factors, the impact of roadway lighting and other features of driver vision, perception, and performance. Collisions may result from a driver's inability to notice delineation, recognize warnings, and other possible road safety controls during various lighting conditions. Hence we compare the relative accident involvement ratio (RAIR) of collisions of millions of drivers from two U.S. States over an 11-year period, 1991–2001. We associate collision trends through RAIR with bathtub curves that are commonly identified with product failure and reliability engineering. Hence we observe the need for improved and automated driver's license testing techniques and applications, especially as these relate to the visual and cognitive abilities of drivers of all ages. Our findings may ultimately improve motorist safety, save lives, and benefit numerous other states, countries, and agencies, including, but not limited to, aviation, commercial vehicles, maritime, and rail sectors, among others.     

新能源汽车消费促进政策对潜在消费者购买意愿的影响

如何提升潜在消费者的购买意愿对于促进新能源汽车市场发展至关重要。本文以SOR理论为基础,通过对河南省洛阳市四个县区的问卷调查,运用结构方程模型分析了新能源汽车消费促进政策对潜在消费者的影响。结果表明：①消费促进政策通过感知价值和感知风险对潜在消费者的购买意愿产生影响,其中充电政策的影响最大,路权政策次之,再次是宣传政策,购车政策的影响最小。因此,购车政策退坡后新能源汽车销量大幅下滑的局面不太可能发生。②潜在消费者更加关注新能源汽车的前期感知价值而较少关注后期的使用风险,宣传政策、购车政策及充电政策越完备,潜在消费者对新能源汽车的感知价值越高,越能激发其购买意愿。③在不同群体间,收入和教育背景对新能源汽车购买意愿的调节作用比较明显,高收入高学历的潜在消费者更加关注购车后的使用权益保障,即路权政策以及充电政策,而低学历低收入的潜在消费者更加关注前期的消费权益保障,即购车政策的经济激励。在政策各环节对感知风险的影响路径上,低收入以及低学历群体的感知风险普遍比高学历高收入群体要显著。鉴于此,本文提出,新能源汽车消费促进政策应注重充电市场的完善,将购车经济补贴政策逐步向充电基础设施以及路权优惠政策方面转移,且针对不同层次的潜在消费者要实施差异化、多元化的促销政策。     

A Revised Economic Analysis of Restrictions on the Use of Cell Phones While Driving

Evidence that cell phone use while driving increases the risk of being involved in a motor vehicle crash has led policymakers to consider prohibitions on this practice. However, while restrictions would reduce property loss, injuries, and fatalities, consumers would lose the convenience of using these devices while driving. Quantifying the risks and benefits associated with cell phone use while driving is complicated by substantial uncertainty in the estimates of several important inputs, including the extent to which cell phone use increases a driver's risk of being involved in a crash, the amount of time drivers spend using cell phones (and hence their aggregate contribution to crashes, injuries, and fatalities), and the incremental value to users of being able to make calls while driving. Two prominent studies that have investigated cell phone use while driving have concluded that the practice should not be banned. One finds that the benefits of calls made while driving substantially exceed their costs while the other finds that other interventions could reduce motor vehicle injuries and fatalities (measured in terms of quality adjusted life years) at a lower cost. Another issue is that cell phone use imposes increased (involuntary) risks on other roadway users. This article revises the assumptions used in the two previous analyses to make them consistent and updates them using recent data. The result is a best estimate of zero for the net benefit of cell phone use while driving, a finding that differs substantially from the previous study. Our revised cost-effectiveness estimate for cell phone use while driving moves in the other direction, finding that the cost per quality adjusted life year increases modestly compared to the previous estimate. Both estimates are very uncertain.     

Redesigning the Downtown of an Expansive Sunbelt City: The Phoenix Case

ABSTRACT

Non-motorized traffic safety is a major public health concern, especially in the sprawling sunbelt cities of the United States. Phoenix is ranked quite high on the number of pedestrian and cyclist crashes in North American cities. This article analyses non-motorist safety incidents in downtown Phoenix. Non-motorist safety concerns were addressed by examining crash types in order to suggest adequate safety treatments. We also demonstrated the use of a countermeasure framework for higher crash locations denominated hotspots. Our findings indicate that it is important to implement a combination of countermeasures to reduce the high number of non-motorist crashes in city centers.     

A Risk-Based Method for Modeling Traffic Fatalities

We describe a risk-based analytical framework for estimating traffic fatalities that combines the probability of a crash and the probability of fatality in the event of a crash. As an illustrative application, we use the methodology to explore the role of vehicle mix and vehicle prevalence on long-run fatality trends for a range of transportation growth scenarios that may be relevant to developing societies. We assume crash rates between different road users are proportional to their roadway use and estimate case fatality ratios (CFRs) for the different vehicle-vehicle and vehicle-pedestrian combinations. We find that in the absence of road safety interventions, the historical trend of initially rising and then falling fatalities observed in industrialized nations occurred only if motorization was through car ownership. In all other cases studied (scenarios dominated by scooter use, bus use, and mixed use), traffic fatalities rose monotonically. Fatalities per vehicle had a falling trend similar to that observed in historical data from industrialized nations. Regional adaptations of the model validated with local data can be used to evaluate the impacts of transportation planning and safety interventions, such as helmets, seat belts, and enforcement of traffic laws, on traffic fatalities.