Jessica B. Cicchino

Effectiveness of forward collision warning and autonomous emergency braking systems in reducing front-to-rear crash rates

The objective of this study was to evaluate the effectiveness of forward collision warning (FCW) alone, a low-speed autonomous emergency braking (AEB) system operational at speeds up to 19mph that does not warn the driver prior to braking, and FCW with AEB that operates at higher speeds in reducing front-to-rear crashes and injuries. Poisson regression was used to compare rates of police-reported crash involvements per insured vehicle year in 22 U.S. states during 2010-2014 between passenger vehicle models with FCW alone or with AEB and the same models where the optional systems were not purchased, controlling for other factors affecting crash risk. Similar analyses compared rates between Volvo 2011-2012 model S60 and 2010-2012 model XC60 vehicles with a standard low-speed AEB system to those of other luxury midsize cars and SUVs, respectively, without the system. FCW alone, low-speed AEB, and FCW with AEB reduced rear-end striking crash involvement rates by 27%, 43%, and 50%, respectively. Rates of rear-end striking crash involvements with injuries were reduced by 20%, 45%, and 56%, respectively, by FCW alone, low-speed AEB, and FCW with AEB, and rates of rear-end striking crash involvements with third-party injuries were reduced by 18%, 44%, and 59%, respectively. Reductions in rear-end striking crashes with third-party injuries were marginally significant for FCW alone, and all other reductions were statistically significant. FCW alone and low-speed AEB reduced rates of being rear struck in rear-end crashes by 13% and 12%, respectively, but FCW with AEB increased rates of rear-end struck crash involvements by 20%. Almost 1 million U.S. police-reported rear-end crashes in 2014 and more than 400,000 injuries in such crashes could have been prevented if all vehicles were equipped with FCW and AEB that perform similarly as systems did for study vehicles.

Trends in older driver crash involvement rates and survivability in the United States: An update

OBJECTIVE Previous research has shown that fatal crash involvement rates per licensed driver aged 70 and older declined significantly more per year in the United States than rates for middle-aged drivers aged 35-54 during 1997-2008, and per vehicle mile traveled from 1995-1996 to 2001-2002. Analyses of police-reported crash data during 1997-2005 indicated that the greater declines for older drivers were due to decreases in crash involvement and in the risk of dying in the crashes that occurred. The current study examined if trends in crash rates, crash involvements, and survivability persisted into more recent years. METHODS Trends for drivers 70 and older were compared with trends for drivers aged 35-54 for U.S. national fatal passenger vehicle crash involvements per 100,000 licensed drivers during 1997-2012 and for U.S. national fatal passenger vehicle crash involvements per vehicle miles traveled in 1995-1996, 2001-2002, and 2008. Using police-reported crash data during 1997-2008 from 20 U.S. states, trends in involvement rates in non-fatal crashes of various severities per 100,000 licensed drivers and changes in the odds of death and the odds of death or serious injury in a crash were compared between older and middle-aged drivers. RESULTS During 2007-2012, declines in national fatal crash involvement rates per licensed driver were similar for drivers 70 and older and middle-aged drivers (18 percent each). However, when considering the entire study period, fatal crash involvement rates continued to reflect a substantially larger decline for drivers 70 and older than for middle-aged drivers (42 vs. 30 percent per licensed driver during 1997-2012, 39 vs. 26 percent per vehicle mile traveled from 1995-2006 to 2008). When analyses of police-reported crash data were extended through 2008, non-fatal injury crash involvement rates per licensed driver declined more for older than for middle-aged drivers (39 vs. 30 percent), and unlike in prior research, average annual declines were significantly larger for drivers 80 and older. Property damage-only crash involvement rates similarly declined significantly more for older than for middle-aged drivers (15 vs. 3 percent). Drivers 70 and older in 1997 were 3.5 times more likely than middle-aged drivers to die in a crash, and this ratio declined to 3.2 by 2008. CONCLUSIONS Although declines in fatal crash involvement rates in recent years have not differed between older and middle-aged drivers, this did not undo earlier gains for older drivers. The recent slowing in the relative magnitude of the decline for older drivers may be related to the differential effect of the U.S. recession on fatal crash involvements of drivers in these age groups. The decreased likelihood of being involved in a crash of any severity and increased survivability when a crash occurred held when examining data through 2008, and for drivers 80 and older, significant declines in crash involvement relative to middle-aged drivers extended to non-fatal injury crashes.

Experiences of Model Year 2011 Dodge and Jeep Owners With Collision Avoidance and Related Technologies

Objective: Crash avoidance technologies have the potential to prevent or mitigate many crashes, but their effectiveness depends on drivers’ acceptance and proper use. Owners of 2011 Dodge Charger, Dodge Durango, and Jeep Grand Cherokee vehicles were interviewed about their experiences with their vehicles’ technologies. Methods: Interviews were conducted in April 2013 with 215 owners of Dodge and Jeep vehicles with adaptive cruise control and forward collision warning and 215 owners with blind spot monitoring and rear cross-path detection. Results: Most owners said that they always keep each collision avoidance technology turned on, and more than 90% of owners with each system would want the technology again on their next vehicle. The majority believed that the systems had helped prevent a collision; this ranged from 54% of drivers with forward collision warning to more than three-quarters with blind spot monitoring and rear cross-path detection. Some owners reported behavioral changes with the systems, but overreliance on them is not prevalent. Reported use of the systems varied by the age and gender of the driver and duration of vehicle ownership to a greater degree than in previous surveys of luxury Volvo and Infiniti vehicles with collision avoidance technologies. Notably, drivers aged 40 and younger were most likely to report that forward collision warning had alerted them multiple times and that it had prevented a collision and that they follow the vehicle ahead less closely with adaptive cruise control. Reports of waiting for the alert from forward collision warning before braking were infrequent but increased with duration of ownership. However, these reports could reflect confusion of the system with adaptive cruise control, which alerts drivers when braking is necessary to maintain a preset speed or following distance but a crash is not imminent. Conclusions: Consistent with previous surveys of luxury vehicle owners with collision avoidance technologies, acceptance and use remains high among owners of more mainstream vehicles. Varying experiences with the technologies by driver age and gender suggest that safety benefits are not uniform for all drivers, and differential benefits may become increasingly apparent as collision avoidance technologies become available to a more heterogeneous population of drivers. The potential for overreliance on the technologies should continue to be monitored, especially as drivers gain more experience with them.

Prevalence of Driver Physical Factors Leading to Unintentional Lane Departure Crashes

ABSTRACT Objective: Some lane-keeping assist systems in development and production provide autonomous braking and steering to correct unintentional lane drift but otherwise require drivers to fully control their vehicles. The goal of this study was to quantify the proportion of drivers involved in unintentional lane drift crashes who would be unable to regain control of their vehicles to inform the design of such systems. Methods: The NHTSAs National Motor Vehicle Crash Causation Survey collected in-depth, on-scene data for a nationally representative sample of 5,470 U.S. police-reported passenger vehicle crashes during 2005–2007 that occurred between 6 a.m. and midnight and for which emergency medical services were dispatched. The physical states of drivers involved in the 631 lane drift crashes in the sample, which represented 259,034 crashes nationally, were characterized. Results: Thirty-four percent of drivers who crashed because they drifted from their lanes were sleeping or otherwise incapacitated. These drivers would be unlikely to regain full control of their vehicles if an active safety system prevented their initial drift. An additional 13% of these drivers had a nonincapacitating medical issue, blood alcohol concentration (BAC) ≥ 0.08%, or other physical factor that may not allow them to regain full vehicle control. When crashes involved serious or fatal injuries, 42% of drivers who drifted were sleeping or otherwise incapacitated, and an additional 14% were impacted by a nonincapacitating medical issue, BAC ≥ 0.08%, or other physical factor. Conclusions: Designers of active safety systems that provide autonomous lateral control should consider that a substantial proportion of drivers at risk of lane drift crashes are incapacitated. Systems that provide only transient corrective action may not ultimately prevent lane departure crashes for these drivers, and drivers who do avoid lane drift crashes because of these systems may be at high risk of other types of crashes when they attempt to regain control. Active lane-keeping assist systems may need to be combined with in-vehicle driver monitoring to identify incapacitated drivers and safely remove them from the roadway if the systems are to reach their maximum potential benefit.

Effects of lane departure warning on police-reported crash rates

OBJECTIVE To evaluate the effects of lane departure warning (LDW) on single-vehicle, sideswipe, and head-on crashes. METHOD Police-reported data for the relevant crash types were obtained from 25 U.S. states for the years 2009-2015. Observed counts of crashes with fatalities, injuries, and of all severities for vehicles with LDW were compared with expected counts based on crash involvement rates for the same passenger vehicles without LDW, with exposure by vehicle series, model year, and lighting system standardized between groups. For relevant crashes of all severities and those with injuries, Poisson regression was used to estimate the benefits of LDW while also controlling for demographic variables; fatal crashes were too infrequent to be modeled. RESULTS Without accounting for driver demographics, vehicles with LDW had significantly lower involvement rates in crashes of all severities (18%), in those with injuries (24%), and in those with fatalities (86%). Adding controls for driver demographics in the Poisson regression reduced the estimated benefit of LDW only modestly in crashes of all severities (11%, p < 0.05) and in crashes with injuries (21%, p < 0.07). CONCLUSIONS Lane departure warning is preventing the crash types it is designed to address, even after controlling for driver demographics. Results suggest that thousands of lives each year could be saved if every passenger vehicle in the United States were equipped with a lane departure warning system that performed like the study systems. PRACTICAL APPLICATIONS Purchase of LDW should be encouraged, and, because drivers do not always keep the systems turned on, future efforts should focus on designing systems to encourage greater use and educating consumers about the benefits of using the systems.

Buick Lucerne Drivers’ Experiences With Rear Parking Sensors

Objective: Rear parking sensors may have the potential to reduce property damage caused by some low-speed backing crashes, but their effectiveness depends on drivers’ acceptance and proper use. This study examined owners’ experiences with Buick Lucerne models with a rear parking sensor system. Methods: Mail surveys were conducted in May 2013 with 426 owners of model year 2010–11 Buick Lucerne sedans equipped with the optional Ultrasonic Rear Parking Assist feature. Results: Respondents were primarily older drivers, with 95% older than 60 and 70% older than 70. Nearly all owners reported that they always leave the system on, do not find it distracting, and would want it on their next vehicle. Slightly more than half (56%) said they had heard an alert and noticed something behind their vehicle they did not expect, which most commonly was a person or animal. Owners who said their behavior had changed while using the system mostly reported positive changes (e.g., increased alertness or confidence). In addition to an audible alert, systems on 2010 models provide information on the distance to rear objects via lights located near the rear windshield; 26% of owners with these systems reported never seeing the lights illuminate while backing up, and the percentage increased with age. Conclusions: Acceptance of the system was high, which is consistent with prior research on early adopters of rear parking sensors. Few owners reported problems using the system, and most problems were likely not attributed to age-related impairments, with the exception of those who did not see the 2010 models warning lights. Use and acceptance of collision avoidance technologies should continue to be assessed among drivers of all ages as the systems become more widely available.

Survey about pedestrian safety and attitudes toward automated traffic enforcement in Washington, D.C.

Objective: Pedestrians represent more than one third of all traffic deaths in Washington, D.C. The District plans to expand its long-standing automated traffic enforcement program in 2013 from speed and red light cameras to cameras to enforce pedestrian right-of-way laws at crosswalks and stop sign laws. This study collected information on the opinions, behaviors, and knowledge of D.C. residents related to camera enforcement and pedestrian safety issues. Methods: A telephone survey of 801 adult D.C. residents was conducted in November 2012 with approximately equal numbers of respondents in each of D.C.s eight wards. Quotas were used to ensure that the sample was representative of the demographic characteristics of adults in each ward. For analyses combining responses across the wards, data were weighted to correspond with the demographic characteristics of adults in the city. Results: Most respondents believed that drivers speeding, running red lights, running stop signs, and not stopping for pedestrians are serious threats to their safety. Respondents strongly supported the speed and red light camera programs, with 76 percent of respondents favoring speed cameras and 87 percent favoring red light cameras. Support was more limited for the camera enforcement that was not yet in place at the time of the survey, with 50 percent of respondents favoring stop sign cameras and 47 percent of respondents favoring crosswalk cameras. Twenty-four percent of respondents had not driven a car in D.C. in the past month, and higher proportions of these nondrivers favored speed cameras (90%), stop sign cameras (67%), and crosswalk cameras (59%) than respondents who drove in D.C. in the past month. Respondents who supported camera enforcement cited safety as their main reason. More than 9 in 10 respondents knew that D.C. law requires drivers to stop for pedestrians crossing the street in marked crosswalks at intersections without traffic signals and midblock, but only 54 percent knew that drivers must stop for pedestrians crossing the street at intersections without marked crosswalks. Conclusions: Most residents supported speed cameras and red light cameras, but support was lower for stop sign and crosswalk cameras. Emphasizing the safety benefits of stop sign and crosswalk cameras and documenting the extent of safety problems at stop signs and crosswalks may increase support for these new forms of camera enforcement. Communities considering automated enforcement should take into account the opinions of pedestrians, even though they are not subject to camera citations.

Effects of rearview cameras and rear parking sensors on police-reported backing crashes

ABSTRACT Objective: The objective of this study was to examine the effectiveness of rearview cameras, rear parking sensors, and both systems combined in preventing police-reported backing crashes. Methods: Negative binomial regression was used to compare rates of police-reported backing crash involvements per insured vehicle year in 22 U.S. states during 2009–2014 between passenger vehicle models with backing technologies and the same vehicle models where the optional systems were not purchased, controlling for other factors affecting crash risk. Rearview cameras were examined from four automakers, rear parking sensors from 2 automakers, and both systems combined from a single automaker. Results: Rearview cameras reduced backing crash involvement rates by 17%. Reductions were larger for drivers 70 and older (36%) than for drivers younger than 70 (16%); however, estimates for older and younger drivers did not differ significantly from one another. The Buick Lucernes rear parking sensor system reduced backing crash involvement rates significantly by 34%, but the reduction for Mercedes-Benz vehicles fit with a sensor system was small and not statistically significant. When averaged between the 2 automakers, effects were significantly larger for drivers 70 and older (38% reduction) than for drivers younger than 70 (1% increase); effects were significant for older but not younger drivers. Backing crash involvement rates were 13% lower among Mercedes-Benz vehicles with a rearview camera and parking sensors than among vehicles without, but this finding was not significant. Discussion: Rearview cameras are effective in preventing police-reported backing crashes. Effects of rear parking sensors are less straightforward; it is unclear whether the Buick Lucerne systems benefits are due to the older age of its drivers, characteristics of the vehicle or system, or a combination. Systems may be especially beneficial to older drivers who might have limitations that make backing challenging. Although effect estimates did not differ significantly between older and younger drivers for both system types, the magnitude of the differences was large and the pattern of results was consistent across 6 of the 7 systems examined. When rear visibility systems become required equipment on new passenger vehicles in 2018, rearview cameras can be expected to prevent 1 in 6 backing crashes reported to police that involve equipped vehicles.

Effects of blind spot monitoring systems on police-reported lane-change crashes

Abstract Objective: The objective of this study was to examine the effectiveness of blind spot monitoring systems in preventing police-reported lane-change crashes. Methods: Poisson regression was used to compare crash involvement rates per insured vehicle year in police-reported lane-change crashes in 26 U.S. states during 2009–2015 between vehicles with blind spot monitoring and the same vehicle models without the optional system, controlling for other factors that can affect crash risk. Results: Crash involvement rates in lane-change crashes were 14% lower (95% confidence limits −24% to −2%) among vehicles with blind spot monitoring than those without. Discussion: Blind spot monitoring systems are effective in preventing police-reported lane-change crashes when considering crashes of all severities. If every U.S. vehicle in 2015 were equipped with blind spot monitoring that performed like the study systems, it is estimated that about 50,000 crashes could have been prevented.

Driver Acceptance of Adaptive Cruise Control and Active Lane Keeping in Five Production Vehicles

Little is known about how consumers interact with driving automation technology that controls steering, speed, or headway in production vehicles. Forty-eight Insurance Institute for Highway Safety employees used a Honda Civic, Infiniti QX60, Toyota Prius, or Audi A4 or Q7 as a personal vehicle for up to several weeks and completed surveys about their experiences. Agreement about whether adaptive cruise control (ACC) or active lane keeping (ALK) improved driving experience varied significantly among vehicles. The Q7’s ACC improved the driving experience significantly more than its ALK. The Civic’s ALK improved the driving experience more than the Q7’s system, but this effect only approached significance. Drivers were most comfortable using systems on free-flowing interstates and least comfortable using ACC in stop-and-go traffic and ALK on curvy roads. The findings show a range of qualitative differences in driving automation technologies and that use of current technologies likely is limited to low-demand conditions.