Demographic adjustments to driver death rates by vehicle type and size.

OBJECTIVE: Driver death rates per million registered vehicles are often used to compare the real-world crash experiences of vehicles of different types and sizes. However, these rates are affected by the risky behavior of drivers (e.g., speeding, impaired driving, lack of restraint use) that differs by age and gender. This paper presents a method for adjusting driver death rates to account for differences in driver age and gender. METHODS: Driver death rates per million registered vehicles per year were calculated for passenger vehicles of model year 2020. To account for potential differences in driver exposure by age and gender, which can affect motor vehicle crash and injury experience, an algebraic method was used to standardize these rates to a common distribution of female drivers ages 25-64. The standardization depends upon an independent estimate of the relative fatality risk for female drivers ages 25-64. RESULTS: The smallest vehicles tended to have higher driver death rates compared with larger vehicles. However, for sports cars, this trend was reversed; larger sports cars had higher driver death rates. Vehicle types popular with male drivers, such as sports cars and pickups, had standardized death rates that were much lower than the raw rates. CONCLUSIONS: The adjustment for driver age and gender greatly reduced the variability of driver death rates among vehicle types. The procedure used here to adjust driver death rates for driver age and gender can be extended to any situation where it is desired to compare the crash rates of two or more subgroups of a population.

Changes in Traffic Crash Rates After Legalization of Marijuana: Results by Crash Severity.

OBJECTIVE: The objective of this study was to estimate the effects of marijuana legalization and the subsequent onset of retail sales on injury and fatal traffic crash rates in the United States during the period 2009-2019. METHOD: State-by-state quarterly crash rates per mile of travel were modeled as a function of time, unemployment rate, maximum posted speed limit, seat belt use rate, alcohol use rate, percent of miles driven on rural roads, and indicators of legalized recreational marijuana use and sales. RESULTS: Legalization of the recreational use of marijuana was associated with a 6.5% increase in injury crash rates and a 2.3% increase in fatal crash rates, but the subsequent onset of retail marijuana sales did not elicit additional substantial changes. Thus, the combined effect of legalization and retail sales was a 5.8% increase in injury crash rates and a 4.1% increase in fatal crash rates. Across states, the effects on injury crash rates ranged from a 7% decrease to an 18% increase. The effects on fatal crash rates ranged from a 10% decrease to a 4% increase. CONCLUSIONS: The estimated increases in injury and fatal crash rates after recreational marijuana legalization are consistent with earlier studies, but the effects varied across states. Because this is an early look at the time trends, researchers and policymakers need to continue monitoring the data.

Potential lives saved by in-vehicle alcohol detection systems.

OBJECTIVES: The objective of this study was to estimate the number of crash deaths specifically attributable to alcohol-impaired driving, with a focus on various strategies for introducing vehicle-based solutions. If alcohol detection systems are standard in all new vehicles, how many lives could be saved in the near term, and how long will it take to essentially eliminate alcohol-impaired driving? Alternatively, if such systems are offered as an option, how many lives could be saved? METHODS: Fatal crashes in the United States during 2015-2018 were classified by the highest driver blood alcohol concentration (BAC) and the corresponding age category of that driver. Based on the estimates of relative risk (RR) for a given driver group, eliminating alcohol in the driver's blood should lower risk by the attributable proportion, 1 - 1/RR. Multiplying this quantity by the number of deaths for the driver group yielded the estimated number of lives potentially saved if the BACs were reduced to zero. RESULTS: Systems that restrict drivers with any BAC could prevent nearly 12,000 deaths per year, while systems that restrict BAC to less than 0.08 g/dL could prevent more than 9,000 deaths. Within 3 years of a mandate for vehicle-based alcohol detection systems, it is expected that the annual lives saved would be between 1,000 and 1,300. Within 6 years, it would be between 2,000 and 2,600 lives saved per year, and within 12 years it would be between 4,600 and 5,900 lives saved per year. A system required only for those convicted of alcohol-impaired driving could save between 800 and 1,000 lives per year. A system available only to fleets of vehicles could save between 300 and 500 lives per year. CONCLUSIONS: Vehicle-based interventions will not immediately solve the problem of alcohol-impaired driving, but they are an important component of the overall strategy. Even if required as standard equipment in all new vehicles, it will take 12 years before there are enough to reach more than half of their potential. If vehicle-based interventions are instead voluntary or introduced as options, then progress toward a solution will be much slower.

Effects of Washington State's alcohol ignition interlock laws on DUI recidivism: An update.

OBJECTIVE: The objective of this study was to examine the effects of changes to Washington State's alcohol ignition interlock laws: moving issuance of interlock orders from the courts to the driver licensing department (July 2003); extending the interlock order requirement to all persons convicted of driving under the influence (DUI; June 2004); allowing an interlock in lieu of an administrative driver's license suspension (January 2009); and requiring proof of interlock installation to reinstate the driver's license (January 2011). METHOD: Trends in conviction types, interlock installation rates, and 2-year cumulative recidivism rates were examined for first-time and repeat offenders with convictions stemming from DUI arrests during 1999-2012. Autoregressive integrated moving average (ARIMA) models examined the association between law changes and installation rates, law changes and recidivism rates, and installation rates and recidivism rates. RESULTS: During the study period, there was a large increase in the proportion of first-time DUI arrests reduced to alcohol-related negligent/reckless driving convictions, offenses not requiring interlock orders. The interlock installation rate increased substantially and the recidivism rate declined substantially among both first and repeat offenders. Based on the ARIMA models for first offenders, the 2004 and 2009 law changes were associated with increased interlock installation rates and lower recidivism rates. For first offenders arrested during the last quarter of 2012, the model estimates a 26% reduction in the recidivism rate (from an expected 7.7% without the 4 laws to 5.6%). A 1 percentage point increase in the interlock installation rate was associated with a 0.06 percentage point decline in the recidivism rate among first offenders. If the association carried forward and if the installation rate had been 100% rather than 38% in the last quarter of 2012, the 2-year recidivism rate would have been reduced from 5.6 to 2%. Among repeat offenders, the 2003 and 2009 law changes were associated with increased interlock installation rates, and the 2009 law change was associated with a nonsignificant decline in recidivism. CONCLUSIONS: In Washington, rates of interlock installations increased as interlock laws were strengthened, and the increase was associated with reductions in recidivism among first DUI offenders. Washington's experience suggests that states can reduce DUI recidivism by requiring interlock orders for all offenders, allowing offenders to install interlocks in lieu of an administrative driver's license suspension, and closing statutory loopholes that allow plea reductions to convictions without interlock orders.

Effects of an integrated collision warning system on teenage driver behavior.

INTRODUCTION: Crash warning systems have been shown to provide safety benefits, but no studies have examined how teenagers respond. This study sought to find out whether young, inexperienced drivers change behavior in response to warnings. METHODS: Forty 16-17 year-olds drove an instrumented vehicle equipped with a system that warned for lane departures and potential rear-end and lane change/merge crashes. Participants were randomly assigned to experimental or control groups, and their driving was monitored for 14weeks during 2011-12. For the experimental group, this included a treatment period, when crash alerts were received by drivers, and baseline and post-treatment periods, when warnings were recorded but not received. The control group never received warnings. Data were analyzed to determine whether warnings were associated with changes in driving behavior. RESULTS: A total of 15,039 trips were analyzed. Lane drifts accounted for 73% of warnings. Forward collision warning rates doubled for all drivers during the treatment period and continued at an increased rate post-treatment. This was likely a result of the fact that, as time went on, all drivers spent more time following vehicles at close distances. Receiving alerts was associated with effects on following and lane-changing behavior, including more time spent following at close distances (17%), fewer lateral drifts (37%) and fewer unsignaled lane changes (80%). Receiving warnings wasn't associated with an increased likelihood of engaging in secondary tasks. CONCLUSIONS: Warning systems may result in improved lane-keeping and turn-signal behaviors by novice drivers, but there is some indication they may result in more close-following behaviors. PRACTICAL APPLICATIONS: There is some evidence that lane departure warning may improve turn-signal use for young drivers. While there is no evidence of safety benefits from the other types of warnings, there is some evidence of an increase in close-following behavior but no increase in secondary tasks due to the presence of those capabilities.

Relationship of traffic fatality rates to maximum state speed limits.

OBJECTIVES: The objective of this study was to examine the safety effects of increases in U.S. state maximum speed limits during the period 1993-2013. METHODS: Poisson regression was used to model state-by-state annual traffic fatality rates per mile of travel as a function of time, the unemployment rate, the percentage of the driving age population that was younger than 25, per capita alcohol consumption, and the maximum posted speed limit on any road in the state. Separate analyses were conducted for all roads, interstates and freeways, and all other roads. RESULTS: A 5 mph increase in the maximum state speed limit was associated with an 8% increase in fatality rates on interstates and freeways and a 4% increase on other roads. In total, there were an estimated 33,000 more traffic fatalities during the years 1995-2013 than would have been expected if maximum speed limits had not increased. In 2013 alone, there were approximately 1,900 additional deaths-500 on interstates/freeways and 1,400 on other roads. CONCLUSIONS: There is a definite trend of increased fatality risk when speed limits are raised. As roadway sections with higher speed limits have become more ubiquitous, the increase in fatality risk has extended beyond these roadways. The increase in risk has been so great that it has now largely offset the beneficial effects of some other traffic safety strategies. State policy makers should keep this trade-off in mind when considering proposals to raise speed limits.

Factors Associated With Retention Among Non-Perinatally HIV-Infected Youth in the HIV Research Network.

BACKGROUND: The transmission of human immunodeficiency virus (HIV) among youth through high-risk behaviors continues to increase. Retention in Care is associated with positive clinical outcomes and a decrease in HIV transmission risk behaviors. We evaluated the clinical and demographic characteristics of non-perinatally HIV (nPHIV)-infected youth associated with retention 1 year after initiating care and in the 2 years thereafter. We also assessed the impact retention in year 1 had on retention in years 2 and 3. METHODS: This was a retrospective analysis of treatment-naive nPHIV-infected 12- to 24-year-old youth presenting for care in 16 US HIV clinical sites within the HIV Research Network between 2002 and 2008. Multivariate logistic regression identified factors associated with retention. RESULTS: Of 1160 nPHIV-infected youth, 44.6% were retained in care during the first year, and 22.4% were retained in all 3 years. Retention in the first year was associated with starting antiretroviral therapy in the first year (adjusted odds ratio [AOR], 3.47 [95% confidence interval (CI), 2.57-4.67]), Hispanic ethnicity (AOR, 1.66 [95% CI, 1.08-2.56]), men who have sex with men (AOR, 1.59 [95% CI, 1.07-2.36]), and receiving care at a pediatric site (AOR, 5.37 [95% CI, 3.20-9.01]). Retention in years 2 and 3 was associated with being retained 1 year after initiating care (AOR, 7.44 [95% CI, 5.11-10.83]). CONCLUSION: A high proportion of newly enrolled nPHIV-infected youth were not retained for 1 year, and only 1 in 4 were retained for 3 years. Patients who were Hispanic, were men who have sex with men, or were seen at pediatric clinics were more likely to be retained in care. Interventions that target those at risk of being lost to follow up are essential for this high-risk population.

Relationship of Near-Crash/Crash Risk to Time Spent on a Cell Phone While Driving.

OBJECTIVES: The objective of this study was to examine in a naturalistic driving setting the dose-response relationship between cell phone usage while driving and risk of a crash or near crash. How is the increasing use of cell phones by drivers associated with overall near-crash/crash risk (i.e., during driving times both on and off the phone)? METHODS: Day-to-day driving behavior of 105 volunteer subjects was monitored over a period of 1 year. A random sample was selected comprised of 4 trips from each month that each driver was in the study, and in-vehicle video was used to classify driver behavior. The proportion of driving time spent using a cell phone was estimated for each 3-month period and correlated with overall crash and near-crash rates for each period. Thus, it was possible to test whether changes in an individual driver's cell phone use over time were associated with changes in overall near-crash/crash risk. RESULTS: Drivers in the study spent 11.7% of their driving time interacting with a cell phone, primarily talking on the phone (6.5%) or simply holding the phone in their hand or lap (3.7%). The risk of a near-crash/crash event was approximately 17% higher when the driver was interacting with a cell phone, due primarily to actions of reaching for/answering/dialing, which nearly triples risk (relative risk = 2.84). However, the amount of driving time spent interacting with a cell phone did not affect a driver's overall near-crash/crash risk. Vehicle speeds within 6 s of the beginning of each call on average were 5-6 mph lower than speeds at other times. CONCLUSIONS: Results of this naturalistic driving study are consistent with the observation that increasing cell phone use in the general driving population has not led to increased crash rates. Although cell phone use can be distracting and crashes have occurred during this distraction, overall crash rates appear unaffected by changes in the rate of cell phone use, even for individual drivers. Drivers compensate somewhat for the distraction by conducting some of the more demanding tasks, such as reaching for or dialing a cell phone, at lower speeds. It is also possible that cell phones and other electronic devices in cars are changing how drivers manage their attention to various tasks and/or changing the kinds of secondary tasks in which they engage.

Secondary Behavior of Drivers on Cell Phones.

OBJECTIVES: The objective of this study was to determine whether cell phone use by drivers leads to changes in the frequency of other types of potentially distracting behavior. There were 2 main questions of interest: (1) As each driver changes cell phone use, does he or she change the amount of driving time spent on other distracting behavior? (2) As each driver changes cell phone use, does he or she change the amount of driving time spent looking away from the driving task? METHODS: Day-to-day driving behavior of 105 volunteer subjects was monitored over a period of 1 year. The amount of driving time during each trip spent on tasks secondary to driving (or looking away from the driving task) was correlated to the amount of time on a cell phone, taking into account the relationships among trips taken by the same driver. RESULTS: Drivers spent 42% of the time engaging in at least one secondary activity. Drivers were talking on a cell phone 7% of the time, interacting in some other way with a cell phone 5% of the time, and engaging in some other secondary activity (sometimes in conjunction with cell phone use) 33% of the time. Other than cell phone use, the most common secondary activities were interacting with a passenger (12% of driving time), holding but not otherwise interacting with an object (6%), and talking/singing/dancing to oneself (5%). Drivers were looking straight forward 81% of the time, forward left or right 5% of time, in a mirror 4% of the time, and elsewhere (eyes off driving task) 10% of time. On average, for each 1 percentage point increase in cell phone talking, the other secondary behavior rate decreased by 0.28 percentage points (P <.0001), and the rate of eyes off driving task decreased by 0.02 percentage points (P =.0067). For each 1 percentage point increase in the amount of other cell phone interaction per trip, the other secondary behavior rate decreased by 0.08 percentage points (P =.0558), but the rate of eyes off driving task increased by 0.06 percentage points (P <.0001). CONCLUSIONS: Although using a cell phone can be distracting from the driving task, other secondary activities can be equally or more distracting, at least as measured by eye glances away from the road ahead and mirrors. In this group of drivers, dialing, reaching for, and answering the cell phone were associated with increased eyes off driving task, as opposed to the decrease in eyes off driving task associated with talking on the phone. Predictions about the effect of cell phone usage on driver distraction need to consider what other behavior is being displaced by the time spent on the phone. A focus by researchers, policy-makers, and the media on the distraction of using cell phones while driving may lead drivers to disregard the risk of other secondary behavior that is even more distracting.

The Effects of Vehicle Redesign on the Risk of Driver Death.

OBJECTIVES: This study updates a 2006 report that estimated the historical effects of vehicle design changes on driver fatality rates in the United States, separate from the effects of environmental and driver behavior changes during the same period. In addition to extending the period covered by 8 years, this study estimated the effect of design changes by model year and vehicle type. METHODS: Driver death rates for consecutive model years of vehicle models without design changes were used to estimate the vehicle aging effect and the death rates that would have been expected if the entire fleet had remained unchanged from the 1985 calendar year. These calendar year estimates are taken to be the combined effect of road environment and motorist behavioral changes, with the difference between them and the actual calendar year driver fatality rates reflecting the effect of changes in vehicle design and distribution of vehicle types. The effects of vehicle design changes by model year were estimated for cars, SUVs, and pickups by computing driver death rates for model years 1984-2009 during each of their first 3 full calendar years of exposure and comparing with the expected rates if there had been no design changes. RESULTS: As reported in the 2006 study, had there been no changes in the vehicle fleet, driver death risk would have declined during calendar years 1985-1993 and then slowly increased from 1993 to 2004. The updated results indicate that the gradual increase would have continued through 2006, after which driver fatality rates again would have declined through 2012. Overall, it is estimated that there were 7,700 fewer driver deaths in 2012 than there would have been had vehicle designs not changed. Cars were the first vehicle type whose design safety generally exceeded that of the 1984 model year (starting in model year 1996), followed by SUVs (1998 models) and pickups (2002 models). By the 2009 model year, car driver fatality risk had declined 51% from its high in 1994, pickup driver fatality risk had declined 61% from its high in 1988, and SUV risk had declined 79% from its high in 1988. The risk of driver death in 2009 model passenger vehicles was 8% lower than that in 2008 models and about half that in 1984 models. CONCLUSIONS: Changes in vehicles, whether from government regulations and consumer testing that led to advanced safety designs or from other factors such as consumer demand for different sizes and types of vehicles, have been key contributors to the decline in U.S. motor vehicle occupant crash death rates since the mid-1990s. Since the early 1990s, environmental and behavioral risk factors have not shown similar improvement, until the recession of 2007, even though there are many empirically proven countermeasures that have been inadequately applied.

Single genome analysis reveals genetic characteristics of Neuroadaptation across HIV-1 envelope.

BACKGROUND: The widespread use of highly effective, combination antiretroviral therapy (cART) has led to a significant reduction in the incidence of HIV-associated dementia (HAD). Despite these advances, the prevalence of HIV-1 associated neurocognitive disorders (HANDs) has been estimated at approximately 40%-50%. In the cART era, the majority of this disease burden is represented by asymptomatic neurocognitive impairment and mild neurocognitive disorder (ANI and MND respectively). Although less severe than HAD, these diagnoses carry with them substantial morbidity. RESULTS: In this cross-sectional study, single genome amplification (SGA) was used to sequence 717 full-length HIV-1 envelope (env) clade B variants from the paired cerebrospinal fluid (CSF) and blood plasma samples of fifteen chronically infected HIV-positive individuals with normal neurocognitive performance (NCN), ANI and MND. Various degrees of compartmentalization were found across disease states and history of cART utilization. In individuals with compartmentalized virus, mean HIV-1 env population diversity was lower in the CSF than plasma-derived variants. Overall, mean V1V2 loop length was shorter in CSF-derived quasispecies when compared to contemporaneous plasma populations, and this was found to correlate with a lower mean number of N-linked glycosylation sites in this region. A number of discrete amino acid positions that correlate strongly with compartmentalization in the CSF were identified in both variable and constant regions of gp120 as well as in gp41. Correlated mutation analyses further identified that a subset of amino acid residues in these compartmentalization "hot spot" positions were strongly correlated with one another, suggesting they may play an important, definable role in the adaptation of viral variants to the CSF. Analysis of these hot spots in the context of a well-supported crystal structure of HIV-1 gp120 suggests mechanisms through which amino acid differences at the identified residues might contribute to viral compartmentalization in the CSF. CONCLUSIONS: The detailed analyses of SGA-derived full length HIV-1 env from subjects with both normal neurocognitive performance and the most common HAND diagnoses in the cART era allow us to identify novel and confirm previously described HIV-1 env genetic determinants of neuroadaptation and relate potential motifs to HIV-1 env structure and function.

Real-world injury patterns associated with Hybrid III sternal deflections in frontal crash tests.

OBJECTIVE: This study investigated the relationship between the peak sternal deflection measurements recorded by the Hybrid III 50th percentile male anthropometric test device (ATD) in frontal crash tests and injury and fatality outcomes for drivers in field crashes. METHODS: ATD sternal deflection data were obtained from the Insurance Institute for Highway Safety's 64 km/h, 40 percent overlap crashworthiness evaluation tests for vehicles with seat belt crash tensioners, load limiters, and good-rated structure. The National Automotive Sampling System Crashworthiness Data System (NASS-CDS) was queried for frontal crashes of these vehicles in which the driver was restrained by a seat belt and air bag. Injury probability curves were calculated by frontal crash type using the injuries coded in NASS-CDS and peak ATD sternal deflection data. Fatality Analysis Reporting System (FARS) front-to-front crashes with exactly one driver death were also studied to determine whether the difference in measured sternal deflections for the 2 vehicles was related to the odds of fatality. RESULTS: For center impacts, moderate overlaps, and large overlaps in NASS-CDS, the probability of the driver sustaining an Abbreviated Injury Scale (AIS) score ≥ 3 thoracic injury, or any nonextremity AIS ≥ 3 injury, increased with increasing ATD sternal deflection measured in crash tests. For small overlaps, however, these probabilities decreased with increasing deflection. For FARS crashes, the fatally injured driver more often was in the vehicle with the lower measured deflection in crash tests (55 vs. 45%). After controlling for other factors, a 5-mm difference in measured sternal deflections between the 2 vehicles was associated with a fatality odds ratio of 0.762 for the driver in the vehicle with the greater deflection (95% confidence interval = 0.373, 1.449). CONCLUSIONS: Restraint systems that reduce peak Hybrid III sternal deflection in a moderate overlap crash test are beneficial in real-world crashes with similar or greater overlap but likely have a disbenefit in crashes with small overlap. This may occur because belt-force limiters employed to control deflections allow excursion that could produce contact with interior vehicle components in small overlaps, given the more oblique occupant motion and potential inboard movement of the air bag. Although based on a limited number of cases, this interpretation is supported by differences in skeletal fracture locations among drivers in crashes with different overlaps. Current restraint systems could be improved by designs that reduce sternal deflection in moderate and large overlap crashes without increasing occupant excursion in small overlap crashes.

Washington State's alcohol ignition interlock law: effects on recidivism among first-time DUI offenders.

OBJECTIVE: To examine the effects of changes to Washington State's ignition interlock laws: moving issuance of interlock orders from courts to the driver licensing department in July 2003 and extending the interlock order requirement to first-time offenders with blood alcohol concentrations (BACs) below 0.15 percent ("first simple driving under the influence [DUI]") in June 2004. METHOD: Trends in conviction types, interlock installation rates, and 2-year cumulative recidivism rates were examined for first-time convictions (simple, high-BAC, test refusal DUI; deferred prosecution; alcohol-related negligent driving) stemming from DUI arrests between January 1999 and June 2006. Regression analyses examined recidivism effects of the law changes and interlock installation rates. To examine general deterrent effects, trends in single-vehicle late-night crashes in Washington were compared with trends in California and Oregon. RESULTS: After the 2004 law change, the proportion of simple DUIs declined somewhat, though the proportion of negligent driving convictions (no interlock order requirement) continued an upward trend. Interlock installation rates for first simple DUIs were 3 to 6 percent in the year before the law change and one third after. Recidivism declined by an estimated 12 percent (e.g., expected 10.6% without law change vs. 9.3% among offenders arrested between April and June 2006, the last study quarter) among first simple DUI offenders and an estimated 11 percent (expected 10.2% vs. 9.1%) among all first-time offenders. There was an estimated 0.06 percentage point decrease in the recidivism rate for each percentage point increase in the proportion of first simple DUI offenders with interlocks. If installation rates had been 100 vs. 34 percent for first simple DUI offenders arrested between April and June 2006, and if the linear relationship between rates of recidivism and installations continued, recidivism could have been reduced from 9.3 to 5.3 percent. With installation rates of 100 vs. 24 percent for all first offenders, their recidivism rate could have fallen from 9.1 to 3.2 percent. Although installation rates increased somewhat after the 2003 law change, recidivism rates were not significantly affected, perhaps due to the short follow-up period before the 2004 law change. The 2004 law change was associated with an 8.3 percent reduction in single-vehicle late-night crash risk. CONCLUSIONS: Mandating interlock orders for all first DUI convictions was associated with reductions in recidivism, even with low interlock use rates, and reductions in crashes. Additional gains are likely achievable with higher rates. Jurisdictions should seek to increase use rates and reconsider permitting reductions in DUI charges to other traffic offenses without interlock order requirements.

Relationship between pedestrian headform tests and injury and fatality rates in vehicle-to-pedestrian crashes in the United States.

Pedestrian protection evaluations have been developed to encourage vehicle front-end designs that mitigate the consequences of vehicle-to-pedestrian crashes. The European New Car Assessment Program (Euro NCAP) evaluates pedestrian head protection with impacts against vehicle hood, windshield, and A-pillars. The Global Technical Regulation No. 9 (GTR 9), being evaluated for U.S. regulation, limits head protection evaluations to impacts against vehicle hoods. The objective of this study was to compare results from pedestrian head impact testing to the real-world rates of fatal and incapacitating injuries in U.S. pedestrian crashes. Data from police reported pedestrian crashes in 14 states were used to calculate real-world fatal and in- capacitating injury rates for seven 2002-07 small cars. Rates were 2.17-4.04 per 100 pedestrians struck for fatal injuries and 10.45-15.35 for incapacitating injuries. Euro NCAP style pedestrian headform tests were conducted against windshield, A-pillar, and hoods of the study vehicles. When compared with pedestrian injury rates, the vehicles' Euro NCAP scores, ranging 5-10 points, showed strong negative correlations (-0.6) to injury rates, though none were statistically significant. Data from the headform impacts for each of the study vehicles were used to calculate that vehicle's predicted serious injury risk. The predicted risks from both the Euro NCAP and GTR 9 test zones showed high positive correlations with the pedestrian fatal and incapacitating injury rates, though few were statistically significant. Whether vehicle stiffness is evaluated on all components of vehicle front ends (Euro NCAP) or is limited to hoods (GTR 9), softer vehicle components correspond to a lower risk of fatality.

Mutations in MAP3K1 cause 46,XY disorders of sex development and implicate a common signal transduction pathway in human testis determination.

Investigations of humans with disorders of sex development (DSDs) resulted in the discovery of many of the now-known mammalian sex-determining genes, including SRY, RSPO1, SOX9, NR5A1, WT1, NR0B1, and WNT4. Here, the locus for an autosomal sex-determining gene was mapped via linkage analysis in two families with 46,XY DSD to the long arm of chromosome 5 with a combined, multipoint parametric LOD score of 6.21. A splice-acceptor mutation (c.634-8T>A) in MAP3K1 segregated with the phenotype in the first family and disrupted RNA splicing. Mutations were demonstrated in the second family (p.Gly616Arg) and in two of 11 sporadic cases (p.Leu189Pro, p.Leu189Arg)-18% prevalence in this cohort of sporadic cases. In cultured primary lymphoblastoid cells from family 1 and the two sporadic cases, these mutations altered the phosphorylation of the downstream targets, p38 and ERK1/2, and enhanced binding of RHOA to the MAP3K1 complex. Map3k1 within the syntenic region was expressed in the embryonic mouse gonad prior to, and after, sex determination. Thus, mutations in MAP3K1 that result in 46,XY DSD with partial or complete gonadal dysgenesis implicate this pathway in normal human sex determination.

Cell phone use while driving and attributable crash risk.

OBJECTIVES: Prior research has estimated that crash risk is 4 times higher when talking on a cell phone versus not talking. The objectives of this study were to estimate the extent to which drivers talk on cell phones while driving and to compute the implied annual number of crashes that could have been avoided if driver cell phone use were restricted. METHODS: A national survey of approximately 1200 U.S. drivers was conducted. Respondents were asked to approximate the amount of time spent driving during a given day, number of cell phone calls made or received, and amount of driving time spent talking on a cell phone. Population attributable risk (PAR) was computed for each combination of driver gender, driver age, day of week, and time of day. These were multiplied by the corresponding crash counts to estimate the number of crashes that could have been avoided. RESULTS: On average, drivers were talking on cell phones approximately 7 percent of the time while driving. Rates were higher on weekdays (8%), in the afternoon and evening (8%), and for drivers younger than 30 (16%). Based on these use rates, restricting cell phones while driving could have prevented an estimated 22 percent (i.e., 1.3 million) of the crashes in 2008. CONCLUSIONS: Although increased rates of cell phone use while driving should be leading to increased crash rates, crash rates have been declining. Reasons for this paradox are unclear. One possibility is that the increase in cell phone use and crash risk due to cell phone use have been overestimated. Another possibility is that cell phone use has supplanted other driving distractions that were similarly hazardous.

Perceptions and experiences of participants in a study of in-vehicle monitoring of teenage drivers.

OBJECTIVES: To assess the perceptions and experiences of participants in a study of a device that monitored teenagers' driving. METHODS: A device that continuously monitors and reports risky driving maneuvers was installed in vehicles of 84 newly licensed teenagers. Study groups varied by whether parents had access to a Web site that summarized their teenagers' driving and by whether in-vehicle alerts provided feedback to drivers. Recruitment of subjects and problems with the device were documented. Teenagers and parents were interviewed after removal of the device. RESULTS: Although the study was conducted in a large urban area, recruitment progressed slowly. Parents who declined to participate usually said their teenagers opposed it, or they were concerned about intruding on the privacy of their children or jeopardizing trust with them. Both parents and teenagers thought in-vehicle alerts helped teenagers drive more safely, although two thirds of teenagers tried to drown out the alerts with loud music. Parents found the Web site useful but reported fewer Web site visits over time. Most parents would prefer receiving information through summary report cards rather than through a Web site. Both parents and teenagers thought the overall system was effective in improving teenagers' driving. Most parents said the Web site and/or device helped them talk to their teenagers about their driving. Parents thought the most effective system would be an in-vehicle alert with immediate parental notification; teenagers preferred a system allowing them to correct behavior before parental notification. CONCLUSIONS: The difficulties in recruiting families for a study of in-vehicle monitoring and feedback technology suggest that gaining broad acceptance may be challenging. Although many teenagers were annoyed by the technology, most said they drove more safely because of it. Sending report cards to parents and allowing teenagers to correct behavior before parents are notified may increase the usefulness and acceptability of monitoring systems.

Long-term effects of handheld cell phone laws on driver handheld cell phone use.

OBJECTIVES: As of October 2009, seven U.S. states and the District of Columbia (D.C.) ban driving while talking on a handheld cell phone. Long-term effects on driver handheld phone use in D.C., New York State, and Connecticut were examined. METHODS: The percentage of drivers talking on handheld cell phones was measured over time with daytime observation surveys in the jurisdictions with bans and comparison jurisdictions without bans. Trends were modeled using Poisson regression to estimate differences between actual rates and rates that would have been expected without a ban. RESULTS: The D.C. ban immediately lowered the percentage of drivers talking on handheld cell phones by 41 percent. Nearly 5 years later, the rate was 43 percent lower than would have been expected without the ban. Use in Connecticut declined 76 percent immediately after the ban; 3.5 years later, use was 65 percent lower than would have been expected without the ban. In New York, use declined 47 percent immediately after the ban; 7 years later, use was 24 percent lower than expected without the ban. Fifteen months after the laws took effect, compliance in New York was lower than in D.C., and the difference appeared due to more intensive enforcement in D.C. However, this linkage is no longer clear because enforcement in New York picked up such that 2008 levels of enforcement appeared comparable in D.C. and New York, whereas enforcement in Connecticut lagged behind. In all three jurisdictions, the chance that a violator would receive a citation was low, and there were no publicized targeted enforcement campaigns. CONCLUSIONS: Jurisdictional bans have reduced handheld phone use and appear capable of maintaining reductions for the long term. However, it is unknown whether overall phone use is lower because many drivers may have switched to hands-free devices. Further research is needed to determine whether reduced handheld cell phone use has reduced crashes.

Effects of in-vehicle monitoring on the driving behavior of teenagers.

OBJECTIVES: The objective was to determine if teenage driving behavior improves when a monitoring and feedback device is installed in the teen's vehicle. METHODS: Vehicles of 85 teenage drivers were fit with a device that detected all instances of sudden braking/acceleration, speeding, and nonuse of seat belts. Drivers were assigned randomly to one of four research groups, differing in whether or not an alert sounded in the vehicle and whether or not parents were given access to websites containing notification records. Time trends in event rates per mile traveled were compared using Poisson regression. RESULTS: Seat belt use improved when violations were reported to the parent websites, and improved even more when in-vehicle alerts were activated. Consistent reductions in speeding were achieved only when teenagers received alerts about their speeding behavior, believed their speeding behavior would not be reported to parents if corrected, and when parents were being notified of such behavior by report cards. CONCLUSIONS: Electronic monitoring of teenage drivers can reduce the incidence of risky behavior, especially seat belt nonuse. More complicated behavior is more difficult to change, however. IMPACT ON INDUSTRY: Parent participation is key to successful behavioral modification, but it is yet to be determined how best to encourage such participation.

Effect of enhanced seat belt reminders on driver fatality risk.

OBJECTIVE: Enhanced seat belt reminders in automobiles have been shown to increase belt use rates by approximately 3 percentage points. The objective of this study was to estimate the effect of enhanced seat belt reminders on driver fatality risk. METHOD: Data included all passenger vehicle driver deaths and vehicle registration counts in the United States for calendar years 2000-2007. Driver fatality rates per vehicle registration per year were compared for otherwise identical vehicle models with and without enhanced seat belt reminders. RESULTS: Driver fatality rates were 6% lower for vehicles with enhanced seat belt reminders compared with vehicles without enhanced belt reminders. After adjusting for vehicle age differences, the estimated effect of enhanced belt reminders on driver fatality risk ranged from a 9% reduction for General Motors vehicles to a 2% increase for Honda vehicles. Combining all manufacturers, enhanced belt reminders reduced fatality risk by approximately 2%. Although not statistically significant, the 2% reduction in fatality risk agrees with what should be expected from a 3 percentage point increase in seat belt use rates. CONCLUSIONS: Enhanced seat belt reminders have raised driver belt use rates and reduced fatality rates, but more aggressive systems may be needed for some drivers. It can be inferred that nonfatal injury rates also have been reduced. IMPACT ON INDUSTRY: Manufacturers should be encouraged to put enhanced seat belt reminders on all vehicles as soon as possible.