Temporal factors in motor vehicle crash deaths.

OBJECTIVE: To summarize fatal motor vehicle crash deaths in the United States by time of day, day of week, month, and season, and to determine why some days of the year tend to experience a relatively high number of deaths. METHOD: Crash deaths were identified and categorized using the Fatality Analysis Reporting System. Days of the year with relatively high crash deaths were compared to the two days that occurred exactly one week before and one week after. RESULTS: On average, motor vehicle crashes in the United States result in more than 100 deaths per day, but there is much day-to-day variability. During 1986-2002 the single day fatality count ranged from a low of 45 to a high of 252. Summer and fall months experience more crash deaths than winter and spring, largely due to increased vehicle travel. July 4 (Independence Day) has more crash deaths on average than any other day of the year, with a relatively high number of deaths involving alcohol. January 1 (New Year's Day) has more pedestrian crash deaths on average, plus it has the fifth largest number of deaths per day overall, also due to alcohol impairment. On other days the high numbers of deaths are likely due to increases in holiday or recreational travel. CONCLUSION: Every day of the year results in many crash deaths, but certain days stand out as particularly risky. The temporal and geographic spread of crash deaths, as well as the view of driving as a routine task, inures the public to this continuing problem. Innovative strategies are needed both to raise awareness and to work toward a solution.

Effectiveness of Ford's belt reminder system in increasing seat belt use.

OBJECTIVES: The study investigated the effectiveness in increasing seat belt use of Ford's belt reminder system, a supplementary system that provides intermittent flashing lights and chimes for five minutes if drivers are not belted. METHODS: Seat belt use of drivers in relatively new cars with and without the reminder system was unobtrusively observed as vehicles were brought to dealerships for service. RESULTS: Overall use rates were estimated at 71% for drivers in vehicles without the reminder system and 76% for drivers in vehicles with belt reminders (p<0.01). CONCLUSIONS: Seat belt use is relatively low in the United States. The present study showed that vehicle based reminder systems can be at least modestly effective in increasing belt use, which may encourage further development of such systems.

New evidence concerning fatal crashes of passenger vehicles before and after adding antilock braking systems.

Fatal crash rates for passenger cars and vans were compared for the last model year before four-wheel antilock brakes were introduced and the first model year for which antilock brakes were standard equipment. A prior study, based on fatal crash experience through 1995, reported that vehicle models with antilock brakes were more likely than identical but 1-year-earlier models to be involved in crashes fatal to their own occupants, but were less likely to be involved in crashes fatal to occupants of other vehicles. Overall, there was no significant effect of antilocks on the likelihood of fatal crashes. Similar analyses, based on fatal crash experience during 1996-98, yielded very different results. During 1996-98, vehicles with antilock brakes were again less likely than earlier models to be involved in crashes fatal to occupants of other vehicles, but they were no longer overinvolved in crashes fatal to their own occupants.

Effect of Florida's graduated licensing program on the crash rate of teenage drivers.

On 1 July 1996, Florida instituted a graduated licensing program for drivers younger than age 18. For the first 3 months, holders of learner's licenses are not allowed to drive at all between 19:00 and 06:00 h; thereafter, they may drive until 22:00 h. Learner's licenses must be held for 6 months prior to eligibility for the intermediate license. Sixteen-year-old intermediate license holders are not permitted to drive unsupervised from 23:00 to 06:00 h, 17 year-olds from 01:00 to 06:00 h. All drivers younger than 18 have strict limits on the number of traffic violations they can accumulate and, effective 1 January 1997, all drivers younger than 21 are subject to a zero tolerance law for drinking and driving. Florida crash data for 1995-1997 were obtained and compared with similar data from Alabama, a state that borders Florida but does not have graduated licensing. For 15, 16, and 17 year-olds combined, there was a 9% reduction in the fatal and injury crash involvement rate in Florida during 1997, the first full year of graduated licensing, compared with 1995. On a percentage basis, crashes declined most among 15 year-olds, followed by 16 year-olds and then 17 year-olds. Reductions were not seen among Alabama teenagers nor among 18 year-olds in Florida.

Visual perception and working memory in schizotypal personality disorder.

OBJECTIVE: Patients affected by schizophrenia show deficits in both visual perception and working memory. The authors tested early-stage vision and working memory in subjects with schizotypal personality disorder, which has been biologically associated with schizophrenia. METHOD: Eleven subjects who met DSM-III-R criteria for schizotypal personality disorder and 12 normal comparison subjects were evaluated. Performance thresholds were obtained for tests of visual discrimination and working memory. Both form and trajectory processing were evaluated for each task. RESULTS: Subjects with schizotypal personality disorder showed intact discrimination of form and trajectory but were impaired on working memory tasks. CONCLUSIONS: These data suggest that subjects with schizotypal personality disorder, unlike patients affected by schizophrenia, have relatively intact visual perception. Subjects with schizotypal personality disorder do show specific deficits on tasks of comparable difficulty when working memory demands are imposed. Schizotypal personality disorder may be associated with a more specific visual processing deficit than schizophrenia, possibly reflecting disruption of frontal lobe systems subserving visual working memory operations.

Relationship of head restraint positioning to driver neck injury in rear-end crashes.

Insurance claims were examined for evidence of neck injuries to drivers of passenger cars struck in the rear. Neck injury rates were significantly lower for male drivers, elderly drivers, and drivers in less severe crashes. Even after accounting for differences in driver demographics and crash severity, neck injury rates were significantly lower for drivers of cars with head restraints that were more likely to be behind the heads of motorists.

Changes in motor vehicle occupant fatalities after repeal of the national maximum speed limit.

Trends in motor vehicle occupant deaths over 8 years were studied for 24 states that raised interstate speed limits and seven states that did not following the 1995 repeal of the US National Maximum Speed Limit. Fatalities on interstates increased 15% in the 24 states that raised speed limits. After accounting for changes in vehicle miles of travel, fatality rates were 17% higher following the speed limit increases. Similar increases were reported following the 1987 speed limit increases on rural interstates. Deaths on roads other than interstates were essentially unchanged.

Evaluation of red light camera enforcement in Oxnard, California.

Red light cameras are increasingly being used to supplement police efforts to enforce against noncompliance with traffic signals--a substantial contributing factor in urban motor vehicle crashes. Camera enforcement is intended to modify driver behavior through both general deterrence and punishment of individual violators. A before/after quasi-experimental design with controls was employed to evaluate the influence of a red light camera enforcement program on red light violation rates in the city of Oxnard, CA. A total of 14 intersections (nine camera sites, three non-camera sites, and two control sites) were studied. Overall, the red light violation rate was reduced approximately 42% several months after the enforcement program began. Increases in driver compliance with red lights were not limited to the camera-equipped intersections but spilled over to nonequipped intersections as well. Results of public opinion surveys conducted approximately 6 weeks before, 6 weeks after, and 6 months after the camera enforcement program began indicated that nearly 80% of Oxnard residents support using red light cameras as a supplement to police efforts to enforce traffic signal laws.

Fatal crashes of passenger vehicles before and after adding antilock braking systems.

Fatal crash rates of passenger cars and vans were compared for the last model year before four-wheel antilock brakes were introduced and the first model year for which antilock brakes were standard equipment. Vehicles selected for analysis had no other significant design changes between the model years being compared, and the model years with and without antilocks were no more than two years apart. The overall fatal crash rates were similar for the two model years. However, the vehicles with antilocks were significantly more likely to be involved in crashes fatal to their own occupants, particularly single-vehicle crashes. Conversely, antilock vehicles were less likely to be involved in crashes fatal to occupants of other vehicles or nonoccupants (pedestrians, bicyclists). Overall, antilock brakes appear to have had little effect on fatal crash involvement. Further study is needed to better understand why fatality risk has increased for occupants of antilock vehicles.

Two-vehicle side impact crashes: the relationship of vehicle and crash characteristics to injury severity.

Injury type and severity among front outboard occupants of passenger vehicles struck in the side by another passenger vehicle and recorded in the United States National Accident Sampling System Crashworthiness Data System were examined in relation to the location of impact, the angle of impact, occupant gender and age, seat belt use, the weight and body style of the side-impacted vehicle, and the weight and body style of the striking vehicle. Elderly occupants were three times as likely as younger occupants in similar crashes to be seriously injured. Serious injuries were also more likely for occupants seated on the struck side and occupants of lightweight passenger vehicles. After accounting for vehicle weight differences, struck-side occupants of cars were still much more likely to be seriously injured than struck-side occupants of light trucks. However, among occupants seated on the side of the vehicle opposite the impact, the likelihood of serious injury was higher for those seated in light trucks.

Effectiveness estimates for center high mounted stop lamps: a six-year study.

The center high mounted stop lamp is a supplemental brake light mounted at the height of the rear window that has been required on all new cars sold in the U.S. starting with the 1986 model year. It was intended to reduce the number of rear-end collisions by improving the braking signal recognition of following drivers. Insurance claims for vehicle damage were used to compare the rear-end collision rates of model year 1985 and model year 1986 cars over calendar years 1986-91. After adjusting for the difference in vehicle ages, model year 1986 cars were found to have experienced 5% fewer rear-end collisions than would have been expected without the center high mounted stop lamps.

Effects of exercise training modality on glucose tolerance in men with abnormal glucose regulation.

To determine the effects of exercise training modality on glucose tolerance in men with untreated abnormal glucose regulation, 26 untrained men (age 54 +/- 9 years; mean +/- SD) with either non-insulin-dependent diabetes mellitus (N = 8), impaired glucose tolerance (IGT) (N = 12) or hyperinsulinemia with normal glucose tolerance (N = 6) were studied before and after 20 wk of either strength training (ST) (N = 8), aerobic (treadmill walk/jog) training (AT) (N = 8), or no exercise (control group; N = 10). Plasma concentrations of glucose and insulin were measured after a 12-14 hr fast and during a standard oral glucose tolerance test (OGTT) before and after training. The ST program significantly reduced total plasma glucose area (mmol.l-1.120 min-1) under the OGTT curve (1348 +/- 251 vs 1190 +/- 329, p < 0.05), and plasma glucose levels (mmol.l-1) at 60 min (p < 0.05), 90 min (P < 0.05), and 120 min (p < 0.05) after glucose ingestion. Strength training also lowered the total plasma insulin area (pmol.l-1.120 min-1) under the OGTT curve (60082 +/- 25467 vs 46727 +/- 11273, p < 0.05) as well as plasma insulin levels (pmol.l-1) at fasting (p < 0.05) and at 90 min (p < 0.01) and 120 min (p < 0.05) after glucose ingestion. All men with IGT (four in each training group) normalized their glucose tolerance following the training. There were no significant differences in OGTT results between ST and AT and no changes were observed in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)