Are front crash prevention systems less effective at preventing rear-end crashes where trucks and motorcycles are struck?

OBJECTIVE: Automatic emergency braking (AEB) and forward collision warning (FCW) are effective at preventing rear-end crashes, but they may perform better in some rear-end crash scenarios than others. The goal of this study was to estimate the effects of front crash prevention systems equipped to passenger vehicles in crashes where another passenger vehicle, a medium/heavy truck, or a motorcycle is struck and compare effectiveness by struck vehicle type. METHODS: More than 160,000 two-vehicle rear-end crashes were identified where a passenger vehicle with or without FCW and AEB was the striking vehicle and another passenger vehicle, medium/heavy truck, or motorcycle was the struck vehicle. Poisson regression was used to estimate the effect of front crash prevention by struck vehicle type on rear-end crash rates per registered vehicle year, accounting for the state and year of the crash and the make, model year, class, and engine type of the striking vehicle. RESULTS: Front crash prevention was associated with a 53% reduction in rear-end crash rates when striking another passenger vehicle, which was significantly larger than the reductions of 38% when striking a medium/heavy truck and 41% when striking a motorcycle. Reductions in rear-end injury crash rates when striking a passenger vehicle also were larger than when striking a medium/heavy truck and when striking a motorcycle. DISCUSSION: If all passenger vehicles were equipped with FCW and AEB that were as effective in crashes striking a truck or motorcycle as they are in crashes with another passenger vehicle, over 5,500 additional crashes with medium/heavy trucks and 500 with motorcycles could potentially be prevented annually in the United States above what would be expected from current front crash prevention systems. Extending front crash prevention testing in consumer information programs to include motorcycle and truck targets could encourage auto manufacturers to improve performance in these crash scenarios.

How can front crash prevention systems address more police-reported crashes in the United States?

Government and consumer-information organizations can motivate automakers to address additional crash types through front crash prevention (FCP) testing programs. This study examined the current state of crashes potentially relevant to current and future FCP systems to provide a roadmap for the next crash types that vehicle testing programs in the United States should evaluate. Crash records from 2016 to 2020 were extracted from the Crash Report Sampling System (CRSS) and the Fatality Analysis Reporting System (FARS). Crashes were restricted to ones involving no more than two vehicles where the striking or path-intruding vehicle was a passenger vehicle and a vehicle defect was not coded. Percentages of police-reported crashes, nonfatal-injury crashes, and fatal crashes were computed for different crash types and circumstances. Rear-end and pedestrian crashes evaluated in existing FCP testing programs accounted for 27% of all police-reported crashes, 19% of nonfatal-injury crashes, and 18% of fatal crashes. The remaining crash types relevant to FCP accounted for 25% of police-reported crashes, 31% of nonfatal-injury crashes, and 23% of fatal crashes. A turning passenger vehicle crossing the path of an oncoming vehicle accounted for the largest proportion of the remaining police-reported (8%) and nonfatal-injury crashes (13%). Head-on crashes accounted for the largest proportion of remaining fatal crashes (9%). Most FCP-relevant police-reported crashes occurred on roads with a posted speed limit between 30 and 50 mph. Medium/heavy trucks were the crash partner in a disproportionate number of fatal head-on and rear-end crashes and motorcycles in a disproportionate number of fatal rear-end and turning crossing-path crashes. Fatal bicyclist and pedestrian crashes were overrepresented at night. The findings from this study indicate that testing organizations should evaluate FCP performance at higher speeds; with non-passenger vehicles and vulnerable road users; during the night; and in more complex head-on and turning crash scenarios to reduce crashes of all severities. Some of these conditions are currently assessed by other testing organizations and can be readily adopted by U.S. programs or possibly addressed with new approaches like virtual testing.

Characteristics of automatic emergency braking responses in passenger vehicles evaluated in the IIHS front crash prevention program.

Researchers can estimate the potential safety benefits of front crash prevention (FCP) systems by simulating system performance in rear-end crash scenarios reported to police or captured during naturalistic driving. Data to support assumptions about FCP systems in production vehicles, particularly automatic emergency braking (AEB), are limited. This study used detailed information from the Insurance Institute for Highway Safety's (IIHS's) FCP evaluation to characterize interventions in vehicles that performed well (superior-rated vehicles) and those that did not perform as well (basic/advanced-rated vehicles) when approaching a stationary surrogate vehicle on a test track at 20 and 40 km/h, and estimated performance in similar conditions at higher speeds. Vehicle and video data from 3,231 IIHS FCP tests conducted at 20 and 40 km/h and 51 IIHS FCP research tests conducted at 50, 60, and 70 km/h with AEB responses were analyzed. Forward collision warning (FCW) and AEB time-to-collision (TTC), mean deceleration, maximum deceleration, and maximum jerk from the beginning of automatic braking to the end of braking or impact were computed for each test. Each dependent measure was modeled with test speed (20 km/h, 40 km/h), IIHS FCP test rating (superior, basic/advanced), and the interaction between test speed and rating. The models were used to estimate each dependent measure at 50, 60, and 70 km/h, and model predictions were compared with the observed performance of six vehicles in IIHS research test data. Vehicles with superior-rated systems warned and began braking earlier, had a greater average rate of deceleration, reached a higher peak deceleration, and had greater jerk than vehicles with basic/advanced-rated systems, on average. The interaction between test speed and vehicle rating was significant in each linear mixed-effects model, indicating that these differences changed with test speed. FCW and AEB in superior-rated vehicles occurred 0.05 and 0.10 s earlier, respectively, per 10-km/h increase in test speed compared with basic/advanced-rated vehicles. Mean deceleration and maximum deceleration for FCP systems in superior-rated vehicles increased 0.65 m/s2 and 0.60 m/s2 more, respectively, per 10-km/h increase in test speed than for systems in basic/advanced-rated vehicles. Maximum jerk increased 2.78 m/s3 per 10-km/h increase in test speed for basic/advanced-rated vehicles but decreased 0.25 m/s3 for systems in superior-rated vehicles. The root mean square error between the observed performance and estimated values at 50, 60, and 70 km/h indicated that the linear mixed-effects model had reasonable prediction accuracy for every measure except jerk at these out-of-sample data points. The findings from this study provide insight into the characteristics that make FCP effective for preventing crashes. Based on performance in the IIHS FCP test, vehicles with superior-rated FCP systems had earlier TTC thresholds and braked with greater deceleration that increased with speed compared with basic/advanced-rated systems. The linear mixed-effects models that were developed can guide assumptions about AEB response characteristics for superior-rated FCP systems in future simulation studies.

Increasing seat belt use in the United States by promoting and requiring more effective seat belt reminder systems.

OBJECTIVE: Federal Motor Vehicle Safety Standard (FMVSS) 208 requires every passenger vehicle to provide an auditory signal lasting 4 to 8 seconds and a visual display lasting 60 seconds when the driver is unbelted at ignition. This requirement does not increase seat belt use. This paper summarizes the latest research on using vehicle technology to increase seat belt use and existing safety standards worldwide to support the strengthening of FMVSS 208. METHOD: Studies of seat belt reminders and interlocks published in peer-reviewed journals, conference proceedings, or as technical reports were identified in online databases and reviewed along with current requirements worldwide. Results from past research were used to estimate the front- and rear-seat daytime belt use rate and the annual number of lives that could be saved by a persistent audible reminder at each seating position. RESULTS: Most motor vehicle occupants routinely buckle up. Those that do not typically forget, are going a short distance, or find belts uncomfortable. Seat belt reminders can remind or motivate occupants to buckle up. Enhanced reminders that exceed FMVSS 208 increase belt use by 6 percentage points. Reminders also can increase rear belt use, and although required throughout the world, are not required by FMVSS 208. More persistent reminders, like those required around the world, with a continuous, long-lasting audible signal increase belt use by 30% among drivers who do not routinely buckle up. If every vehicle in the U.S. had such a reminder at each seating position, then it was estimated that the daytime belt use rate in the U.S. would increase about 3 percentage points from 90.3% to 93.2% in the front row and by about 6 percentage points from 80% to 85.9% in the rear row. It was estimated that the increase in belt use from a continuous, long-lasting audible reminder could potentially save about 1,600 lives each year.Seat belt interlocks can increase belt use, but acceptance is a stumbling block. Public outcry ensued after interlocks were required in 1973, and public sentiment remains negative. Opinions toward front and rear reminders are more favorable. Furthermore, past research suggests interlocks may be no more effective for increasing seat belt use than persistent audible reminders. The effect of interlocks on rear belt use have not been explored. CONCLUSION: Persistent seat belt reminder systems that last at least 90 seconds can potentially save hundreds of U.S. motorists each year. Robust empirical evidence, successful exemplars from organizations throughout the world, and a clear public health benefit exists for strengthening FMVSS 208 to require more persistent audible reminders at every seating position.

Can the speed limit be used as a surrogate for the striking vehicle's travel speed or delta-V in police-reported rear-end crashes?

Objective: A recent study by Kidd (2022) recommended that organizations evaluating front crash prevention (FCP) systems like automatic emergency braking and forward collision warning increase speed differentials in existing test scenarios from 25 mph to 45 mph to make the tests more representative of police-reported rear-end crashes. Kidd used the posted speed limit as a proxy for the striking vehicle's travel speed prior to the crash. The current study used velocity data from event data recorders (EDRs) in rear-end crashes to evaluate this assumption. These same data were used to replicate another study (Farmer 2003) that showed the speed limit was a poor surrogate for delta-V in rear-end crashes.Method: A total of 11,199 crash records during 2017-2020 were extracted from the Crash Investigation Sampling System database. The analysis was restricted to 436 of these records that involved two vehicles with a front-to-rear manner of collision or rear-end crash configuration with EDR data from the striking vehicle. The relationships between the posted speed limit and striking-vehicle travel speed and between the speed limit and delta-V were modeled using regression.Results: On average, the speed limit overestimated striking-vehicle travel speed by 2 mph, but the relationship between the speed limit and travel speed was not linear. The speed limit reasonably approximated travel speed on roads with speed limits of 30 and 50 mph or higher. It slightly overestimated travel speed on roads with 40-45 mph speed limits and underestimated it on roads with limits of 25 mph or less. The probability that the striking vehicle's travel speed was 25 mph or less on any road was 0.09. In contrast, the probability of the striking vehicle's travel speed being 45 mph or less was 0.54 overall and 0.75 or higher for roads with a speed limit between 25 and 45 mph. As found in prior research, there was no significant relationship between the speed limit and delta-V.Conclusion: The posted speed limit was a reasonable surrogate for the striking vehicle's travel speed prior to police-reported rear-end crashes on roads with a speed limit above 25 mph. It was not a reasonable surrogate for delta-V. Travel speeds on roads with speed limits of 25 mph or less were much higher than the speed limit, which suggests that existing scenarios used to evaluate FCP system performance represent travel speeds in fewer police-reported rear-end crashes than previously thought. Increasing speed differentials in existing FCP test scenarios to 45 mph would reflect the striking vehicle's travel speed in three quarters of rear-end crashes on roads with a speed limit of 45 mph or less.

Improving the safety relevance of automatic emergency braking testing programs: An examination of common characteristics of police-reported rear-end crashes in the United States.

OBJECTIVE: Forward collision warning and automatic emergency braking (AEB) systems help prevent rear-end crashes where a vehicle strikes the rear of another. However, the benefits may be limited if the systems are stymied by common crash circumstances or only target scenarios evaluated in vehicle testing programs. This study examined the prevalence of characteristics that may limit AEB system performance in police-reported rear-end crashes and the relevance of scenarios used to evaluate these systems. METHODS: Police-reported rear-end crashes (n = 6,731,215, Crash Report Sampling System) and fatal rear-end crashes (n = 4,285, Fatality Analysis Reporting System) with a fatality in the striking or struck vehicle during 2016-2019 were analyzed. Percentages of police-reported rear-end crashes, nonfatal-injury rear-end crashes, and fatal rear-end crashes were computed to identify common crash characteristics. Roadway speed limit was used as a proxy for striking vehicle speed. RESULTS: A straight-moving vehicle striking a stopped or decelerating vehicle on roads with a speed limit of 40 km/h (25 mph) or less only accounted for 3% of all rear-end crashes, 3% of nonfatal-injury rear-end crashes, and 1% of fatal rear-end crashes. In contrast, 36% of all rear-end crashes, 36% of nonfatal-injury rear-end crashes, and 11% of fatal rear-end crashes involved a straight-moving vehicle striking a stopped or decelerating vehicle on roads with a speed limit between 56 and 72 km/h (35 and 45 mph). A medium or heavy truck was the struck vehicle in 32% of fatal rear-end crashes, and a motorcycle was the struck vehicle in 11% of fatal rear-end crashes. At least one of the following characteristics that may degrade AEB system performance was present in 14% of the rear-end crashes studied: striking vehicle turning; a struck vehicle turning or changing lanes; a struck vehicle that is not a passenger vehicle; wintery weather; wet or icy roads; or a speed limit of 113 km/h (70 mph) or higher. CONCLUSION: Circumstances shown to diminish AEB effectiveness accounted for 14% of rear-end crashes, and scenarios currently used to evaluate AEB systems accounted for 3%. Evaluating AEB systems at speeds up to 72 km/h (45 mph) and incorporating a motorcycle or medium/heavy truck target will make AEB evaluations more representative of police-reported rear-end crashes.

The effects of persistent audible seat belt reminders and a speed-limiting interlock on the seat belt use of drivers who do not always use a seat belt.

INTRODUCTION: Vehicle technologies that increase seat belt use can save thousands of lives each year. Kidd, Singer, Huey, and Kerfoot (2018) found that a gearshift interlock was more effective for increasing seat belt use than an intermittent audible reminder, but interlocks may not be more effective than persistent audible reminders lasting at least 90 seconds. METHOD: Forty-nine part-time belt users with a recent seat belt citation who self-reported not always using a seat belt drove two vehicles for 1 week each. Thirty-three drove a Chevrolet with an intermittent audible reminder followed by either a BMW with a persistent 90-second audible reminder (n = 17) or a Subaru with an incessant audible reminder (n = 16). The other 16 participants experienced the BMW persistent reminder followed by an interlock that limited speed to 15 mph during unbelted driving. These data were combined with data from 32 part-time belt users in Kidd et al. (2018) who experienced the intermittent reminder for 2 weeks or the intermittent reminder for 1 week and a gearshift interlock the next. RESULTS: Relative to the intermittent reminder, seat belt use was significantly increased an estimated 30% by the BMW persistent reminder, 34% by the Subaru incessant reminder, and 33% by the speed-limiting interlock. Belt use was increased an estimated 16% by the gearshift interlock, but this change was not significant. More participants circumvented the speed-limiting interlock to drive unbelted than the audible reminders. Responses to a poststudy survey indicated that interlocks were less acceptable than reminders. CONCLUSIONS: Audible reminders lasting at least 90 seconds and a speed-limiting interlock were more effective for increasing seat belt use than an intermittent audible reminder, but reminders were found more acceptable. Practical applications: Strengthening existing U.S. safety standards to require audible reminders lasting at least 90 seconds for front-row occupants could save up to 1,489 lives annually.

Changes in the sources of distracted driving among Northern Virginia drivers in 2014 and 2018: A comparison of results from two roadside observation surveys.

INTRODUCTION: An increase in distracted driving has been suggested as a factor contributing to the 15% increase in fatal crashes from 2014 to 2016, but objective information about the prevalence of distracted driving in recent years is incomplete or lacking. The current study replicated a 2014 observation study conducted in Northern Virginia to examine whether the prevalence of distracted driving overall and of individual secondary behaviors has changed. METHOD: Drivers of moving or stopped vehicles were observed at 12 locations across 4 Northern Virginia communities during the daytime. The presence of 12 different secondary behaviors was recorded. RESULTS: In 2018, about 23% of drivers were engaged in at least one secondary behavior, which was not significantly different from 2014. Overall phone use was not significantly different between 2014 and 2018. However, the likelihood of holding a cellphone significantly decreased while the likelihood of manipulating a cellphone significantly increased in 2018 relative to 2014. About 14% of drivers were engaged in noncellphone secondary behaviors in 2014 and 2018, which exceeded the proportion using phones in both years. CONCLUSIONS: There was no evidence that distracted driving has become more common in recent years, but the prevalence of some secondary behaviors has changed. Most concerning was the 57% increase in the likelihood of cellphone manipulation in 2018 relative to 2014, a behavior that has been consistently linked to increased crash risk; however, because the behavior is uncommon overall, the increased prevalence would be expected to only slightly increase crash rates. Practical applications: Although cellphone use was frequently observed in 2014 and 2018, collectively, other noncellphone secondary behaviors were more prevalent. Practitioners and policymakers should continue targeting cellphone use, but also must target other common secondary behaviors to fully address distracted driving.

The effect of a gearshift interlock on seat belt use by drivers who do not always use a belt and its acceptance among those who do.

INTRODUCTION: Seat belts reduce the risk of fatal injury in a crash, yet in 2015, nearly 10,000 people killed in passenger vehicles were unrestrained. Enhanced seat belt reminders increase belt use, but a gearshift interlock that prevents the vehicle from being placed into gear unless the seat belt is used may prove more effective. METHOD: Thirty-two people with a recent seat belt citation and who admitted to not always using a seat belt as a driver were recruited as part-time belt users and asked to evaluate two new vehicles. Sixteen drove two vehicles with an enhanced reminder for one week each, and 16 drove a vehicle with an enhanced reminder for one week and a vehicle with a gearshift interlock the following week. Sixteen full-time belt users who reported always using a seat belt drove a vehicle with a gearshift interlock for one week to evaluate acceptance. RESULTS: Relative to the enhanced reminder, the gearshift interlock significantly increased the likelihood that a part-time belt user used a belt during travel time in a trip by 21%, and increased the rate of belt use by 16%; this effect approached significance. Although every full-time belt user experienced the gearshift interlock, their acceptance of the technology reported in a post-study survey was fairly positive and not significantly different from part-time belt users. Six part-time belt users circumvented the gearshift interlock by sitting on a seat belt, waiting for the system to deactivate, or unbuckling during travel. CONCLUSION: The gearshift interlock increased the likelihood that part-time belt users buckled up and the rate of belt use during travel relative to the enhanced reminder but could be more effective if it prevented circumvention. PRACTICAL APPLICATIONS: An estimated 718-942 lives could be saved annually if the belt use of unbuckled drivers and front passengers increased 16-21%.

Rage against the machine? Google's self-driving cars versus human drivers.

INTRODUCTION: Automated driving represents both challenges and opportunities in highway safety. Google has been developing self-driving cars and testing them under employee supervision on public roads since 2009. These vehicles have been involved in several crashes, and it is of interest how this testing program compares to human drivers in terms of safety. METHODS: Google car crashes were coded by type and severity based on narratives released by Google. Crash rates per million vehicle miles traveled (VMT) were computed for crashes deemed severe enough to be reportable to police. These were compared with police-reported crash rates for human drivers. Crash types also were compared. RESULTS: Google cars had a much lower rate of police-reportable crashes per million VMT than human drivers in Mountain View, Calif., during 2009-2015 (2.19 vs 6.06), but the difference was not statistically significant. The most common type of collision involving Google cars was when they got rear-ended by another (human-driven) vehicle. Google cars shared responsibility for only one crash. CONCLUSIONS: These results suggest Google self-driving cars, while a test program, are safer than conventional human-driven passenger vehicles; however, currently there is insufficient information to fully examine the extent to which disengagements affected these results. PRACTICAL APPLICATION: Results suggest that highly-automated vehicles can perform more safely than human drivers in certain conditions, but will continue to be involved in crashes with conventionally-driven vehicles.

Distracting behaviors among teenagers and young, middle-aged, and older adult drivers when driving without and with warnings from an integrated vehicle safety system.

INTRODUCTION: Negative reinforcement from crash warnings may reduce the likelihood that drivers engage in distracted driving. Alternatively, drivers may compensate for the perceived safety benefit of crash warnings by engaging in distractions more frequently, especially at higher speeds. The purpose of this study was to examine whether warning feedback from an integrated vehicle-based safety system affected the likelihood that various secondary behaviors were present among drivers ages 16-17, 20-30, 40-50, and 60-70. METHOD: Participants drove an instrumented sedan with various collision warning systems for an extended period. Ten 5-second video clips were randomly sampled from driving periods at speeds above 25mph and below 5mph each week for each driver and coded for the presence of 11 secondary behaviors. RESULTS: At least one secondary behavior was present in 46% of video clips; conversing with a passenger (17%), personal grooming (9%), and cellphone conversation (6%) were the most common. The likelihood that at least one secondary behavior was present was not significantly different during periods when drivers received warnings relative to periods without warnings. At least one secondary behavior was 21% more likely to be present at speeds below 5mph relative to speeds above 25mph; however, the effect of vehicle speed was not significantly affected by warning presence. Separate models for each of the five most common secondary behaviors also indicated that warnings had no significant effect on the likelihood that each behavior was present. CONCLUSIONS: Collision warnings were not associated with significant increases or decreases in the overall likelihood that teen and adult drivers engaged in secondary behaviors or the likelihood of the behaviors at speeds above 25mph or below 5mph. PRACTICAL APPLICATIONS: There was no evidence that forward collision warning and other technologies like those in this study will increase or decrease distracted driving.

Driver trust in five driver assistance technologies following real-world use in four production vehicles.

OBJECTIVES: Information about drivers' experiences with driver assistance technologies in real driving conditions is sparse. This study characterized driver interactions with forward collision warning, adaptive cruise control, active lane keeping, side-view assist, and lane departure warning systems following real-world use. METHODS: Fifty-four Insurance Institute for Highway Safety employees participated and drove a 2016 Toyota Prius, 2016 Honda Civic, 2017 Audi Q7, or 2016 Infiniti QX60 for up to several weeks. Participants reported mileage and warnings from the technologies in an online daily-use survey. Participants reported their level of agreement with five statements regarding trust in an online post-use survey. Responses were averaged to create a composite measure of trust ranging from -2 (strongly disagree) to +2 (strongly agree) for each technology. Mixed-effect regression models were constructed to compare trust among technologies and separately among the study vehicles. Participants' free-response answers about what they liked least about each system were coded and examined. RESULTS: Participants reported driving 33,584 miles during 4 months of data collection. At least one forward collision warning was reported in 26% of the 354 daily reports. The proportion of daily reports indicating a forward collision warning was much larger for the Honda (70%) than for the Audi (18%), Infiniti (15%), and Toyota (10%). Trust was highest for side-view assist (0.98) and lowest for active lane keeping (0.20). Trust in side-view assist was significantly higher than trust in active lane keeping and lane departure warning (0.53). Trust in active lane keeping was significantly lower than trust in adaptive cruise control (0.67) and forward collision warning (0.71). Trust in adaptive cruise control was higher for the Audi (0.72) and Toyota (0.75) compared with the Honda (0.30), and significantly higher for the Infiniti (0.93). Trust in Infiniti's side-view assist (0.58) was significantly lower than trust in Audi (1.17) and Honda (1.23) systems. Coding of answers to free-response questions showed that more than 80% of complaints about Honda's adaptive cruise control were about the way it functioned and/or performed. Infiniti's side-view assist was the only one with complaints mentioning circumstances where it was used. Trust in forward collision warning, lane departure warning, and active lane keeping was not significantly different among vehicles. CONCLUSIONS: Driver trust varied among driver assistance technologies, and trust in adaptive cruise control and side-view assist differed among vehicles. Trust may affect real-world use of driver assistance technologies and limit the opportunity for the systems to provide their intended benefits.

Differences in glance behavior between drivers using a rearview camera, parking sensor system, both technologies, or no technology during low-speed parking maneuvers.

This study characterized the use of various fields of view during low-speed parking maneuvers by drivers with a rearview camera, a sensor system, a camera and sensor system combined, or neither technology. Participants performed four different low-speed parking maneuvers five times. Glances to different fields of view the second time through the four maneuvers were coded along with the glance locations at the onset of the audible warning from the sensor system and immediately after the warning for participants in the sensor and camera-plus-sensor conditions. Overall, the results suggest that information from cameras and/or sensor systems is used in place of mirrors and shoulder glances. Participants with a camera, sensor system, or both technologies looked over their shoulders significantly less than participants without technology. Participants with cameras (camera and camera-plus-sensor conditions) used their mirrors significantly less compared with participants without cameras (no-technology and sensor conditions). Participants in the camera-plus-sensor condition looked at the center console/camera display for a smaller percentage of the time during the low-speed maneuvers than participants in the camera condition and glanced more frequently to the center console/camera display immediately after the warning from the sensor system compared with the frequency of glances to this location at warning onset. Although this increase was not statistically significant, the pattern suggests that participants in the camera-plus-sensor condition may have used the warning as a cue to look at the camera display. The observed differences in glance behavior between study groups were illustrated by relating it to the visibility of a 12-15-month-old child-size object. These findings provide evidence that drivers adapt their glance behavior during low-speed parking maneuvers following extended use of rearview cameras and parking sensors, and suggest that other technologies which augment the driving task may do the same.

The effectiveness of a rearview camera and parking sensor system alone and combined for preventing a collision with an unexpected stationary or moving object.

OBJECTIVE: This study measured the effectiveness of a parking sensor system, a rearview camera, and a sensor system combined with a camera for preventing a collision with a stationary or moving child-size object in the path of a backing vehicle. BACKGROUND: An estimated 15,000 people are injured and 210 are killed every year in backover crashes involving light vehicles. Cameras and sensor systems may help prevent these crashes. METHOD: The sample included 111 drivers (55 men, 56 women), including 16 in the no-technology condition, 32 in the sensor condition, 32 in the camera condition, and 31 in the camera-plus-sensor condition. A stationary or moving child-size object was surreptitiously deployed in the path of participants backing out of a parking stall. RESULTS: A significantly smaller proportion of participants in the camera condition hit the stationary object compared with participants in the no-technology condition; however, this benefit was greatly reduced when the stationary object was partially or completely in the shade. Significantly fewer participants hit the moving object than the stationary object. The percentage of participants in the sensor, camera, and camera-plus-sensor conditions who hit the moving object was not different from the no-technology condition. CONCLUSION: The camera was the only technology that was effective for preventing collisions with the stationary object. The variation in collision outcomes between the stationary- and moving-object conditions illustrates how the effectiveness of these technologies is dependent on the backing situation. APPLICATION: This research can help the selection and development of countermeasures to prevent backovers.

Driver cellphone and texting bans in the United States: evidence of effectiveness.

Almost all U.S. states have laws limiting drivers' cellphone use. The evidence suggests that all-driver bans on hand-held phone conversations have resulted in long-term reductions in hand-held phone use, and drivers in ban states reported higher rates of hands-free phone use and lower overall phone use compared with drivers in non-ban states. Bans on all phone use by teenage drivers have not been shown to reduce their phone use. The effects of texting bans on the rates of drivers' texting are unknown. With regard to the effects of bans on crashes, 11 peer-reviewed papers or technical reports of all-driver hand-held phone bans and texting bans were reviewed. Some were single-state studies examining crash measures before and after a state ban; other national or multi-state studies compared crashes in states with and without bans over time. The results varied widely. The lack of appropriate controls and other challenges in conducting strong evaluations limited the findings of some studies. Thus, despite the proliferation of laws limiting drivers' cellphone use, it is unclear whether they are having the desired effects on safety. Priorities for future research are suggested.

Visibility of children behind 2010-2013 model year passenger vehicles using glances, mirrors, and backup cameras and parking sensors.

This study identified the areas behind vehicles where younger and older children are not visible and measured the extent to which vehicle technologies improve visibility. Rear visibility of targets simulating the heights of a 12-15-month-old, a 30-36-month-old, and a 60-72-month-old child was assessed in 21 2010-2013 model year passenger vehicles with a backup camera or a backup camera plus parking sensor system. The average blind zone for a 12-15-month-old was twice as large as it was for a 60-72-month-old. Large SUVs had the worst rear visibility and small cars had the best. Increases in rear visibility provided by backup cameras were larger than the non-visible areas detected by parking sensors, but parking sensors detected objects in areas near the rear of the vehicle that were not visible in the camera or other fields of view. Overall, backup cameras and backup cameras plus parking sensors reduced the blind zone by around 90 percent on average and have the potential to prevent backover crashes if drivers use the technology appropriately.

Drivers' attitudes toward front or rear child passenger belt use and seat belt reminders at these seating positions.

OBJECTIVE: Passengers, especially those in rear seating positions, use seat belts less frequently than drivers. In-vehicle technology can inform drivers when their passengers are unbuckled and encourage passengers to use belts. The current study collected information about drivers' attitudes toward passenger belt use and belt reminders for front passengers and children in back seats. METHODS: A national telephone survey of 1218 people 18 and older was conducted, of which 477 respondents were drivers who transport a front seat passenger at least once a week and 254 were drivers who transport an 8- to 15-year-old child in the back seat. Respondents were asked about their attitudes toward belt use by their front passengers or rear child passengers and preferences for different passenger belt reminder features. RESULTS: Ninety percent of drivers who regularly transport front seat passengers said that the passengers always use seat belts. Reported belt use was even higher among 8- to 15-year-old children in the back seat (97%). Among the drivers whose children do not always buckle up, about half said their child unbuckled the belt during the trip. Almost every full-time belt use driver (96%) would encourage front passengers to buckle up if not belted, compared to 57 percent of part-time belt users and nonusers. In contrast, nearly every driver who transports children in the back seat would encourage their belt use, regardless of the driver's belt use habits. Most drivers who transport front passengers wanted passenger belt reminders to encourage passengers to buckle up. Most of these drivers wanted a chime/buzzer or warning light or text display and wanted the reminder to last indefinitely. Most drivers who transport child passengers in the rear seat wanted the vehicle to indicate whether child passengers are unbuckled. A large majority of these drivers wanted notifications via a visual diagram of seating positions and belt use, a chime/buzzer, and a warning light or text display. These drivers also wanted the vehicle to provide belt use information until the child buckled up. CONCLUSIONS: Many drivers, especially those who always use seat belts, said they would encourage unbuckled passengers to buckle up and supported auditory and visual belt reminders for passengers, particularly for children sitting in the back seat. Front and rear passenger reminders that last indefinitely would be acceptable to most drivers who transport these passengers. An auditory alert may be especially useful to alert drivers to children unbuckling in the back seat during a trip.

Attitudes toward seat belt use and in-vehicle technologies for encouraging belt use.

OBJECTIVES: In-vehicle seat belt reminders and interlocks can encourage belt use, but widespread adoption of these features depends on the degree of acceptance among both belted and unbelted occupants. The current study collected information about attitudes toward belt use and in-vehicle technologies for encouraging belt use. METHODS: A national telephone survey of 1218 adult drivers and passengers was conducted using random samples of landline and cell phone numbers. Part-time belt users and nonusers were oversampled. All respondents were asked about frequency of belt use, buckling routines, and support for different types of belt interlocks. Part-time belt users and nonusers were queried in more depth about different types of reminders and reminder strategies. RESULTS: Almost all respondents said that they always use their seat belts (91%). Few said that they did not always (8%) or never (1%) used belts. Driving a short distance (67%), forgetting (60%), and comfort (47%) were common reasons why part-time belt users do not buckle up; comfort (77%), not needing a seat belt (54%), and disliking being told what to do (50%) were most frequently cited among nonusers. When asked about various types of belt interlocks, part-time belt users and nonusers most often said that ignition interlocks would make them more likely to buckle up (70% and 44%, respectively). However, only 44 to 51 percent of all respondents, including full-time belt users, supported using the different types of interlocks to increase belt use. A larger proportion of part-time belt users and nonusers said that they would be more likely to buckle up in response to auditory and haptic reminders than visual reminders. More than two thirds of part-time belt users and at least one third of nonusers said that they would be more likely to buckle up in response to belt reminders that become more intense or continue indefinitely; these reminders would be acceptable to about half of part-time belt users and around one fifth of nonusers. CONCLUSIONS: The Moving Ahead for Progress in the 21st Century (MAP-21) law allows the National Highway Traffic Safety Administration to strengthen minimum requirements for belt reminders or allow the use of interlocks to meet federal safety standards. Even though most people always buckle up, belt interlocks are supported by only about half of full-time belt users and by fewer part-time belt users and nonusers. Enhanced reminder systems are more acceptable than belt interlocks and are viewed as almost as effective as interlocks if persistent enough. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.