Undercounting of large trucks in federal and state crash databases: Extent of problem and how to improve accuracy of truck classifications

Objective: Prior research suggested that single-unit trucks are undercounted when using vehicle body codes in the Fatality Analysis Reporting System (FARS). This study explored the extent of the misclassification and undercounting problem for crashes in FARS and state crash databases.

Methods: Truck misclassifications for fatal crashes were explored by comparing the Trucks Involved in Fatal Accidents (TIFA) database with FARS. TIFA used vehicle identification numbers (VINs) and survey information to classify large trucks. This study used VINs to improve the accuracy of large truck classifications in state crash databases from 5 states (Delaware, Maryland, Minnesota, Nebraska, and Utah).

Results: The vehicle body type codes resulted in a 19% undercount of single-unit trucks in FARS and a 23% undercount of single-unit trucks in state databases. Tractor-trailers were misclassified less often. Misclassifications occurred most frequently among single-unit trucks in the weight classes of 10,001–14,000 pounds.

Conclusions: The amount of misclassification of large trucks is large enough to potentially affect federal and state decisions on traffic safety. Using information from VINs results in more complete and accurate counts of large trucks involved in crashes. The National Transportation Safety Board recommended actions to improve federal and state crash data.     

Do speeding tickets reduce the likelihood of receiving subsequent speeding tickets? A longitudinal study of speeding violators in Maryland

OBJECTIVE: Speeding tickets are the most commonly used tool to deter speeders, yet little is known about how speeding citations affect individual drivers' behavior over time. This study examined the effects of being cited for speeding and types of legal consequences on drivers' subsequent speeding citations, which are an indicator of speeding behavior. METHODS: A cohort of 3,739,951 Maryland licensed drivers were identified and followed for one year. Drivers were categorized by whether or not they received a speeding citation in May 2002. Among those cited for speeding in May 2002, drivers were grouped by type of penalty (fines and points; probation before judgment [PBJ, which results in fines but no points]; or no legal consequences). The relative risks (RR) and 95 percent confidence intervals (CI) of receiving a speeding citation during follow-up were compared between drivers ticketed and not ticketed in May 2002, as well as among different penalty groups. Cox proportional hazards regression modeling was used to adjust for potential confounders, including age, gender, alcohol-impaired driving, and residence. Kaplan-Meier survival functions were used to examine timing of violations. RESULTS: Young drivers and male drivers were more likely to receive a speeding citation. Drivers who received a speeding citation in May 2002 had almost twice the risk of receiving a speeding citation during follow-up, compared with those not cited for speeding that month (RR 1.6, 95% CI 1.52-1.68). Overall legal consequences had no significant effect on the risk of receiving a repeat speeding citation relative to ticketed drivers who escaped those consequences (RR 0.98, 95% CI 0.84-1.15); however, stratified analyses showed a significant decrease in repeat citations among females (RR 0.75, 95% CI 0.63-0.90) and drivers who received PBJ (RR 0.81, 95% CI 0.67-0.96). Kaplan-Meier curves showed that the study group of speeders had a significantly shorter time between May 2002 until receipt of a speeding citation than controls. Among penalty groups, significantly shorter times until receipt of another citation were observed among drivers escaping consequences or receiving fines/points compared with drivers receiving fines/PBJ. CONCLUSIONS: Drivers who receive speeding citations are at increased risk of receiving subsequent speeding citations, suggesting that speeding citations have limited effects on deterrence in the context of the current traffic enforcement system. When comparing different penalties, PBJ is associated with a reduced rate of recidivism more than stronger penalties; however, it is unclear whether the reduction primarily is attributable to the penalty itself or to characteristics of drivers receiving PBJ. Increasing drivers' perceptions that they are at risk of being caught speeding may improve the effectiveness of speeding law enforcement.     

Driver mortality in frontal crashes: comparison of newer and older airbag designs

In 1997, the National Highway Traffic Safety Administration amended its requirements for frontal crash performance under Federal Motor Vehicle Safety Standard 208 to temporarily allow 30 mi/h (48 km/h) sled tests with unbelted dummies as an alternative to 30 mi/h head-on rigid-barrier vehicle tests. This change permitted automakers to reduce airbag inflation forces so that they would be less likely to injure occupants who are close to airbags when they first deploy. Most vehicle models were sled-certified starting in model year 1998. Airbag-related deaths have decreased since 1997; however, controversy persists about whether reduced inflation forces might be decreasing protection for some occupants in high-severity frontal crashes. To examine the effects of the regulatory changes, this study computed rate ratios (RR) and 95% confidence intervals (95% CI) for passenger vehicle driver deaths per vehicle registration during 2000-2002 at principal impact points of 12 o'clock for 1998-99 model year vehicles relative to 1997 models. Passenger vehicles included in the study had both driver and passenger front airbags, had the same essential designs during the 1997-1999 model years, and had been sled-certified for drivers throughout model years 1998 and 1999. An adjustment was made for the higher annual mileage of newer vehicles. Findings were that the effect of the regulatory change varied by vehicle type. For cars, sport utility vehicles, and minivans combined, there was an 11 percent decrease in fatality risk in frontal crashes after changing to sled certification (RR = 0.89; 95% CI = 0.82-0.96). Among pickups, however, estimated frontal fatality risk increased 35 percent (RR = 1.35; 95% CI = 1.12-1.62). For a broad range of frontal crashes (11, 12, and 1 o'clock combined), the results indicated a modest net benefit of the regulatory change across all vehicle types and driver characteristics. However, the contrary finding for pickups needs to be researched further.     

超微气泡富氧+生物活化技术在黑臭水体治理中的工程应用

针对当前黑臭河道治理工作中出现的黑臭反复,长效性难保持问题,以某内源污染严重的重度黑臭河道为例实施原位生态修复。第1阶段采用超微气泡富氧（移动式曝气船+定点式曝气设备）和生物活化技术进行水体和底质修复,削减内源污染,改善生境;第2阶段应用定点式曝气设备、生态浮岛、水生植物净化、水生动物多样性调控进行生态修复,营造健康稳定的生态系统。经过近4个月的治理,治理区水质由重度黑臭稳定达到GB 3838—2002《地表水环境质量标准》Ⅴ类水标准,水体COD、NH₃-N和TP含量分别为28.79,0.36,0.19 mg/L,去除率分别达到45%、98%和85%以上,治理后水体澄清,可见多种水生动物和沉水植物,河道底质呈现自然泥土色泽,在未进行清淤处理的情况下即达到了泥水共治的效果,水环境质量得到显著提升,实现了长效治理。     

Persuasion and licensure: a randomized controlled intervention trial to increase licensure rates among Maryland motorcycle owners

OBJECTIVE: This study aimed to determine whether a persuasive educational intervention could increase licensure among motorcycle owners. Unlicensed motorcycle operators appear to be disproportionately involved in police-reported motorcycle crashes in Maryland, accounting for about 27% of motorcycle operators in police-reported crashes, although unlicensed owners comprise 17% of primary motorcycle owners. METHODS: A randomized controlled trial was conducted among unlicensed owners. Linking Maryland records of registered motorcycles with license files, 8,499 unlicensed owners who had no licensed co-owners were identified. Half were randomized to receive a persuasive educational mailing in early June 2005 from Maryland Motor Vehicle Administration (MVA). Motorcycle licenses can be attained by passing an accredited motorcycle training class or passing knowledge and skills tests administered by the state driver licensing agency. Licensure rates and motorcycle class enrollment were followed for 6 months post-intervention. RESULTS: As of December 16, 2005, 280 intervention group owners had obtained Class M motorcycle licenses and 158 had obtained Class R motorcycle learner's permits. The comparison group obtained 209 M licenses and 122 R permits. The overall success rate in the intervention group, defined as obtaining Class M or R, was 10.4% compared with 7.9% in the comparison group (licensure ratio (LR) = 1.33; 95% confidence interval (CI) = 1.16-1.52). The intervention was most successful among men, whose LR for obtaining M licenses was 1.45 (95% CI = 1.21-1.75). LRs were higher among owners ages 40-48 and 49+ receiving the intervention compared with younger groups. Motorcycle training class enrollment rates were higher in the intervention group, particularly among those taking a course for riders with intermediate skills (enrollment ratio = 2.24; 95% CI = 1.41-3.55). CONCLUSION: The intervention appeared to increase licensure, yet the licensure rate remained low among the intervention group. Potential risks and benefits of increasing the percentage of motorcyclists who are licensed need to be studied.     

三唑酮在设施栽培土壤及大白菜中的消解动态及残留

为评价三唑酮在大白菜施用后的环境安全性,建立了GC测定蔬菜及土壤中三唑酮残留的方法,进行露地与设施栽培条件三唑酮在大白莱和土壤中的消解动态和最终残留研究.在大白菜和土壤中的最低检测质量分数均为0.001 mg/kg,三唑酮的平均加标回收率为81.5％～110.6％,变异系数为1.32％～6.04％.消解动态试验为2倍推荐使用剂量施药1次,三唑酮在设施栽培大白菜的半衰期分别为2.72～3.30 d和3.21～3.35 d;露地栽培为2.35～2.87 d和2.30～3.12 d.设施栽培大白菜中三唑酮残留量与用药量正相关,随着施药量的增加,消解速度减慢,残留量相应增大.研究可为制定三唑酮设施栽培大白菜上最大残留限量和合理使用准则以及风险评估提供科学依据.     

Does the Maryland graduated driver licensing law affect both 16-year-old drivers and those who share the road with them?

PROBLEM: To assess effects of the 1999 Maryland graduated driver licensing (GDL) law on both 16-year-old drivers and other road users. METHOD: Calculation and comparison of crash involvement rates and non-fatal injury rates pre-GDL (1996-1998) and post-GDL (2001-2003) by type of road user, per population, and per licensed driver, with adjustment for trends among 30-59-year-old drivers. RESULTS: Post-GDL, prevalence of licensure decreased 24% among 16-year-olds, and rates of 16-year-old drivers involved in crashes significantly decreased per 16-year-old population (corrected rate ratio (RRc) 0.82; 95% CI (0.71, 0.96)). A significant decrease also was observed for non-fatal injuries per 16-year-old population among 16-year-old drivers involved in crashes (RRc 0.63; 95% CI (0.41, 0.98)). Similarly, decreases, albeit not statistically significant, were observed among their passengers and other vehicle occupants. Per 16-year-old licensed driver, a slight non-significant increase was observed in crash involvement rates; non-fatal injury rates per 16-year-old licensed driver suggest decreased risk (non-significant) among 16-year-old drivers, their passengers, and other vehicle occupants. SUMMARY: Maryland's GDL delayed licensure and reduced crashes and non-fatal injuries among 16-year-old drivers per population. Trends in injuries among other road users involved in crashes with 16-year-old drivers were suggestive of a benefit from GDL, although observed decreases were not significant. Per licensed driver, findings were not significant, but suggested little change in crash involvement and decreased non-fatal injuries. Because one-third fewer 16-year-olds were licensed post-GDL, these results may suggest a selection effect in licensure. IMPACT ON INDUSTRY: Because Maryland had nighttime restrictions for new drivers before 1999, this study suggests other components of GDL are beneficial for drivers and possibly for other road users. States with weak GDL laws should strongly consider revising them.