Drivers’ detection of roadside targets when driving vehicles with three headlight systems during high beam activation
Reagan, Ian J.; Brumbelow, Matthew L.
Accident Analysis and Prevention
A previous open-road experiment indicated that curve-adaptive HID headlights driven with low beams improved drivers’ detection of low conspicuity targets compared with fixed halogen and fixed HID low beam systems. The current study used the same test environment and targets to assess whether drivers’ detection of targets was affected by the same three headlight systems when using high beams. Twenty drivers search and responded for 60 8 × 12 inch targets of high or low reflectance that were distributed evenly across straight and curved road sections as they drove at 30 mph on an unlit two-lane rural road. The results indicate that target detection performance was generally similar across the three systems. However, one interaction indicated that drivers saw low reflectance targets on straight road sections from further away when driving with the fixed halogen high beam condition compared with curve-adaptive HID high beam headlights and also indicated a possible benefit for the curve-adaptive HID high beams for high reflectance targets placed on the inside of curves. The results of this study conflict with the previous study of low beams, which showed a consistent benefit for the curve-adaptive HID low beams for targets placed on curves compared with fixed HID and fixed halogen low beam conditions. However, a comparison of mean detection distances from the two studies indicated uniformly longer mean target detection distances for participants driving with high beams and implicates the potential visibility benefits for systems that optimize proper high beam use.
High beam headlights: self-reported frequency of use, motivations for use, and opinions about advanced headlight technology
Reagan, Ian J.; Cicchino, Jessica B.
Insurance Institute for Highway Safety
This study surveyed drivers in the Ann Arbor, Michigan, area about their use of and motivations for using high beam headlights.
Telephone surveys were conducted during summer 2015 with 604 drivers. Respondents provided information about exposure to nighttime driving, concerns about seeing and crashing at night, prevalence of high beam use on specific area roads when isolated from other traffic, factors that might influence high beam use, and knowledge of and opinions about high beam assist (also called automatic high beam headlamps).
Self-reported use of high beams varied by roadway environment, with 81% of drivers reporting they use high beams always or most of the time on winding rural roads with little or no street lighting, but only 22% saying they use them always or most of the time on city streets with little or no street lighting. The most common motivations for not using high beams were the belief that there was enough lighting in an environment or that drivers did not need them. The extra viewing distance offered by high beams and the avoidance of causing glare for other drivers were the most important factors that influenced drivers’ decisions of when to use high beams. A majority of drivers (60%) agreed that high beam assist sounded like an important safety feature, but only 43% agreed they would want the feature on their next vehicle.
A recent roadside study that observed cars driving in conditions where high beam use was appropriate found actual use to be very low (18%). The much higher rates reported by respondents in the current study indicates they overestimate how often they use high beams. Advanced headlight technologies could address the low use of high beams, but drivers may not accept them out of mistrust in automation.
The effects of rurality, proximity of other traffic, and roadway curvature on high beam headlamp use rates
Reagan, Ian J.; Brumbelow, Matthew L.; Flannagan, Michael J.; Sullivan, John M.
Traffic Injury Prevention
The few observational studies of the prevalence of high beam use indicate the rate of high beam use is about 25% when vehicles are isolated from other vehicles on unlit roads. Recent studies were limited to two-lane rural roads and used measurement methods that likely overestimated use. The current study examined factors associated with the rate of high beam use of isolated vehicles on a variety of roadways in the Ann Arbor, Michigan, area.
Twenty observation sites were categorized as urban, rural, or on a rural/urban boundary and selected to estimate the effects of street lighting, road curvature, and direction of travel relative to the city on high beam use. Sites were selected in pairs so that a majority of traffic passing one site also passed through the other. Measurement of high beams relied on video data recorded for two nights at each site, and the video also were used to derive a precise measure of the proximity of other traffic. Nearly 3,200 isolated vehicles (10 s or longer from other vehicles) were observed, representing 1,500-plus vehicle pairs.
Across the sample, 18% of the vehicles used high beams. Seventy-three percent of the 1500-plus vehicle pairs used low beams at each paired site, whereas 9% used high beams at both sites. Vehicles at rural sites and sites at the boundaries of Ann Arbor were more likely to use high beams than vehicles at urban sites, but use in rural areas compared with rural/urban boundary areas did not vary significantly. Rates at all sites were much lower than expected, ranging from 0.9% to 52.9%. High beam use generally increased with greater time between subject vehicles and leading vehicles and vehicles in the opposing lane. There were mixed findings associated with street lighting, road curvature, and direction of travel relative to the city.
Maximizing visibility available to drivers from headlights includes addressing the substantial underuse of high beam headlamps. Advanced technologies such as high beam assist, which switches automatically between high and low beam headlamps depending on the presence of other traffic, can help to address this problem.
Test track evaluation of headlight glare associated with adaptive curve HID, fixed HID, and fixed halogen low beam headlights
Reagan, Ian J.; Frischmann, Tim; Brumbelow, Matthew L.
Adaptive curve headlights swivel with steering input and are linked to reduced insurance claims and improved visual performance. This study assessed glare experienced from adaptive curve high-intensity discharge (HID), fixed (non-swiveling) HID, and fixed halogen headlights – all tested in low beam mode. Twenty participants rated glare from vehicles’ headlights using the DeBoer visual discomfort scale as a test driver drove towards them from five approaches on a test track. Participants rated the fixed halogen condition as less glaring than the adaptive curve and fixed HID conditions. There was no significant difference in ratings between the HID low beam conditions. Collapsing across roadway approaches, the mean subjective ratings for the fixed halogen, adaptive curve HID, and fixed HID low beam conditions indicated “satisfactory” levels of glare. Differences between subjective ratings were supported by illuminance data. Differences among the three low beam systems appear minor, relative to their differences from a benchmark high beam condition.
A survey of horizontal road curvature for fatal nighttime crashes
Brumbelow, Matthew L.
Proceedings of the 11th International Symposium on Automotive Lighting
Adequate vehicle lighting is an important part of minimizing nighttime crash risk. However, the location and amount of necessary lighting can differ considerably based on the specific road geometry. Information on relevant road geometry variables where crashes occur is needed in order to establish performance criteria that encourage headlight systems with real-world benefits. For the current study, 1,900 road segments where a fatal nighttime crash occurred were investigated. Using satellite imagery and coded variables for each crash, the cases were categorized as occurring on a straight road section, on or near a curve, or at a corner or intersection. For each crash occurring on a curve, the curve radius and length was measured using satellite imagery. The measures of horizontal curvature were compared for different crash scenarios. Overall, 32 percent of the analyzed crashes occurred on road sections with a curve radius less than 500 m. Sixty-two percent occurred on road sections that were straight or had a curve radius greater than 500 m, and 5 percent occurred at corners or intersections. For sections with radii below 500 m, the median curve radius and length were 228 m and 117 m, respectively. For every type of crash analyzed, straight road sections predominated, with the exception of single vehicle crashes with objects off the roadway. Just over half of these crashes occurred on sections with radii less than 500 m. These data can be used to design or evaluate headlight systems relative to the distribution of real-world fatal crash scenarios.
Consumer safety information programs at IIHS
Zuby, David S.
Proceedings of the 24th International Technical Conference on the Enhanced Safety of Vehicles (CD-ROM)
Since 1969, when the Insurance Institute for Highway Safety (IIHS) began publishing results of low-speed crash tests to highlight differences in vehicle bumpers, it has been a significant source of information about how the safety of different vehicle designs varies. Currently, IIHS maintains crashworthiness ratings covering five crash modes along with ratings of front crash prevention (FCP) systems and children’s booster seats, as well as annual updates of insurance loss reports from its affiliate, the Highway Loss Data Institute (HLDI). This report describes the experience with IIHS’s latest consumer information efforts and identifies the next areas of consumer information to come online. It presents information about the number of vehicle models and booster seats evaluated; their ratings assigned as well as media, consumer, and manufacturer response; and small overlap crashworthiness and FCP ratings. Research underpinning future rating programs addressing Lower Anchors and Tethers for Children (LATCH) and advanced head lighting systems also is summarized. Since launching its booster seat ratings, IIHS has evaluated 200 designs for their ability to adjust rear seat belt fit to booster-age children across a wide variety of rear seat belt configurations. The number of models rated Best Bet, indicating they will provide good belt fit in common passenger vehicles, has increased from a low of 10 in 2008 to 69 in 2014. Media coverage of these annual ratings announcements is estimated to average an audience of 88 million people in the United States. IIHS internet pages with booster ratings are among the most viewed, with an average of 102,800 page views monthly. IIHS began rating vehicle front crashworthiness on the basis of a 64 km/h small overlap crash against a rigid barrier in 2012. Of the 118 currently rated 2015 models, 49 are good, 25 acceptable, 23 marginal, and 21 poor. Several models have been tested in two design iterations with improved performance in the second test, indicating automakers are able to design vehicles to better protect occupants in similar crashes. It is estimated that the media coverage across all small overlap ratings announcements has achieved 1.1 billion views. Surveys of automobile dealers indicate that good ratings in this test have led to increased sales, at least in the short term. IIHS ratings of vehicle FCP systems include both warning and autobraking functions. The proportion of new models available with FCP of any kind has increased from 30 to 60 percent. The combined media coverage of three announcements featuring FCP ratings were viewed 212 million times. While not as strong as for crash test ratings, there was indication that these announcements positively affected sales of vehicles with these systems. Large audiences for IIHS consumer information programs have prompted manufacturers of rated products to make changes in ways indicated by IIHS tests. Based on this experience with current programs, there is good reason to believe that IIHS ratings of LATCH and advanced head lighting systems can also improve vehicle safety.
On-road experiment to assess drivers’ detection of roadside targets as a function of headlight system, target placement, and target reflectance
Reagan, Ian J.; Brumbelow, Matthew L.; Frischmann, Tim
Accident Analysis and Prevention
Adaptive headlights swivel with steering input to keep the beams on the roadway as drivers negotiate curves. To assess the effects of this feature on driver’s visual performance, a field experiment was conducted at night on a rural, unlit, and unlined two-lane road during which 20 adult participant drivers searched a set of 60 targets. High- (n = 30) and low- (n = 30) reflectance targets were evenly distributed on straight road sections and on the inside or outside of curves. Participants completed three target detection trials: once with adaptive high-intensity discharge (HID) headlights, once with fixed HID headlights, and once with fixed halogen headlights. Results indicated the adaptive HID headlights helped drivers detect targets that were most difficult to see (low reflectance) at the points in curves found by other researchers to be most crucial for successful navigation (inside apex). For targets placed on straight stretches of road or on the outside of curves, the adaptive feature provided no significant improvement in target detection. However, the pattern of results indicate that HID lamps whether fixed or adaptive improved target detection somewhat, suggesting that part of the real world crash reduction measured for this adaptive system (Highway Loss Data Institute (HLDI), 2012a) may be due to the differences in the light source (HID vs. halogen). Depending on the scenario, the estimated benefits to driver response time associated with the tested adaptive (swiveling HID) headlights ranged from 200 to 380 ms compared with the fixed headlight systems tested.
Perceived discomfort glare from an adaptive driving beam headlight system compared with three low beam lighting configurations
Reagan, Ian J.; Brumbelow, Matthew L.
Adaptive driving beams (ADB) avoid glare for approaching or leading drivers but otherwise provide high beam lighting. Audi's implementation uses a matrix of LED units to deactivate individual LEDs when it detects leading or approaching vehicles. A test track study measured perceived discomfort glare by having 20 participants view and rate headlight configurations from five roadway approaches. The headlight conditions included an Audi A8 with ADB, the A8 with ADB deactivated (resulting in an LED low beam pattern that met European specifications), a 2013 Mazda 3 with low beam adaptive curve HID headlights, and a 2014 Dodge Durango SUV with low beam HID headlights. Five approaches included left and right gradual and sharp curves and a straight approach. Participants rated glare comfort on a scale from 1 to 9, with higher ratings indicating more acceptable glare. Glare from the Durango was rated as less comfortable (M = 6.15) than the other three systems. The Mazda 3 (M = 6.82) received more acceptable glare ratings than the Durango. The A8 ADB (M = 7.25) received more acceptable glare ratings than the Durango and the Mazda 3 but was not rated differently from the A8 low beam LED condition (M = 7.36). Mean and maximum illuminance measures for the approach vehicles corresponded well with subjective ratings. These findings demonstrate the promise for adaptive driving beam headlight systems, and the tested adaptive driving beam system is presently available for use in the European market. However, FMVSS 108 requires discrete high and low beam settings, which does not allow adaptive driving beam systems in the United States. Measuring illuminance dynamically may provide an alternative regulatory approach.
Navigating toward zero fatalities: the role of NCAPs
Nolan, Joseph M.; Karush, Sarah
Journal of the Australasian College of Road Safety
In the nearly 20 years since the Insurance Institute for Highway Safety (IIHS) began publishing crashworthiness ratings for consumer information, great progress has been made in reducing the toll from motor vehicle crashes in the United States. The drop in deaths and injuries during that time continued a trend that began in the 1970’s. Along with important changes in people’s behaviour spurred by cultural and legislative shifts - notably a reduction in alcoholimpaired driving and wider use of seat belts - the improved safety of vehicles has been a key factor in this drop.
Effects of daytime running lights on multiple-vehicle daylight crashes in the United States
Farmer, Charles M.; Williams, Allan F.
Accident Analysis and Prevention
Involvements in multiple-vehicle daylight crashes in nine states over 4 years were analyzed for a group of passenger cars and light trucks equipped with automatic daytime running lights. On average, these vehicles were involved in 3.2% fewer multiple-vehicle crashes than vehicles without daytime running lights (P = 0.0074).
Comment on Theeuwes and Riemersma's revisit of daytime running lights
Williams, Allan F.; Farmer, Charles M.
Accident Analysis and Prevention
This article, by Williams and Farmer, comments on an article written by Theeuwes and Riersma critiquing a 1981 study on daytime running lights. They note that, in "Daytime Running Lights as a Vehicle Collision Countermeasure," Theeuwes and Riemersma (1995) provided a critique of a 1981 study on daytime running lights (DRLs) in Sweden, concluding that the data "fail to show a clear effect of DRL." The authors of this article comment on and take issue with Theeuwes and Riemersma's conclusions, and mention studies that show positive effects of DRLs in reducing crashes.
The prospects of daytime running lights for reducing vehicle crashes in the United States
Williams, Allan F.; Lancaster, Kimberli A.
Public Health Reports
Daytime running lights increase visual contrast between vehicles and their background, improving their noticeability and detectability. Seven countries require motor vehicles to have lights on during all daytime periods--Canada, Denmark, Finland, Hungary, Iceland, Norway, and Sweden. Studies from these and other countries have generally indicated that daytime running lights use is associated with small to moderate reductions in multiple-vehicle daytime crashes, especially those involving vehicles approaching from the front or side. There is evidence also that initial positive effects of daytime running lights do not dissipate over time, that is, there is little support for novelty or habituation effects. The bulk of the evidence suggests that running lights do not lead to increases in collisions involving pedestrians and pedalcyclists, allaying concerns that there would be negative consequences of making these road users relatively less conspicuous. Most of the studies have been conducted in countries located at latitudes that are to the north of most of the continental United States and that have longer twilight periods and generally lower ambient illumination. The concern has been expressed that running lights may lose their effectiveness in countries located at lower latitudes, such as the United States, because the lights will provide less of a contrast. General Motors Corporation and some other manufacturers are now providing running lights on new models with higher intensities than are used in Scandinavian countries. Findings in running lights studies suggest that their effect in the United States will be positive, and their introduction provides an opportunity to determine the effect. The costs of running lights are low, so even modest crash reductions would be cost effective.
The effect of daytime running lights on crashes between two vehicles in Saskatchewan: a study of a government fleet
Sparks, Gordon A.; Neudorf, Russell D.; Smith, Anne E.; Wapman, Kenneth R.; Zador, Paul L.
Accident Analysis and Prevention
Keeping vehicle lights on to increase vehicle conspicuity during daytime hours has been found to reduce crashes in Scandinavia and the United States. Crashes of vehicles with and without daytime running lights owned by the Central Vehicle Agency of the Province of Saskatchewan were compared to a random selection of crashes drawn from provincial crash files involving vehicles without daytime running lights for the years 1982 through 1989. Daytime two-vehicle crashes involving vehicles approaching from the front or side were reduced by about 28% for the daytime running-light equipped vehicles. A 28% reduction in daytime running-light relevant daytime two-vehicle crashes corresponds to a 15% reduction in all daytime two-vehicle crashes.
Fleet experience with daytime running lights in the United States
Stein, Howard S.
SAE Techical Paper Series 851239
Previous research in Canada, Finland, Sweden and the United States has indicated that daytime running lights (DRLs) - vehicle lights that are on during daylight hours - can reduce the frequency of daytime multiple-vehicle crashes. In this study, over 2, 000 passenger cars, vans, and pickup trucks in three fleets were modified to operate with DRLs. An inexpensive relay was installed on these vehicles to automatically turn on their front parking lights and rear tail lights with vehicle ignition. In addition, bulbs with substantially higher intensity minor filaments were installed in the front parking lights. The crash experience of these vehicles was compared to similar but unmodified vehicles in the fleets. Overall, the proportion of multiple-vehicle crashes relevant to DRLs that occurred during daytime hours was seven percent lower for the vehicles equipped with DRLs.