Total Traffic Fatalities Research Articles

Safety and Operational Effectiveness of Protected Only Versus Protected/Permitted Left-Turn Signal Phase

Roadway intersection fatalities account for around 24% of total traffic fatalities each year, with left-turning vehicles associated with most of these crashes. To manage left-turning movements, various left-turn signal phases like protected only (PO), protected/permitted left-turn (PPLT), and flashing yellow arrow (FYA) are currently in use. However, their overall effectiveness has not been well established. The paper evaluates the safety and operational effectiveness of PO over PPLT left-turn signal phase using sample intersections from Louisiana. A total of 151 signalized intersections with uniform left-turn signal phases at all of their approaches were selected. Crash data recorded over five years at those intersections comprising a total of 13,278 crashes, including 1,275 left-turn crashes, were collected. A crash modification factor (CMF) was developed using the negative binomial model (NBM) to assess the safety benefits of PO over PPLT. The Highway Capacity Manual 6th Edition (HCM 6) control delay field measurement technique was used for the operational analysis. The study first developed CMFs for total crashes and only left-turn crashes at various severity levels. CMF of PO over PPLT revealed that PO significantly reduced all severity levels of left-turn crashes by more than 50%, however, it was only able to reduce injury and fatal total crashes. Second, the study found average control delay at PO (50.69 s/vehicle) significantly higher than at PPLT (46.04 s/vehicle). The difference in delay was only significant during the morning peak hour. Overall, from both safety and operation perspectives, the results indicate that PO performs better than PPLT.

United States fatal pedestrian crash hot spot locations and characteristics

US pedestrian fatalities are at their highest level in nearly three decades and account for an increasing share of total traffic fatalities (16%). To achieve the vision of a future transportation system that produces zero deaths, pedestrian safety must be improved. In this study, we screened the entire US roadway network to identify fatal pedestrian crash “hot spot” corridors: 1,000-meter-long sections of roadway where six or more fatal pedestrian crashes occurred during an eightyear period. We identified 34 hot spot corridors during 2001-2008 and 31 during 2009-2016. While only five corridors were hot spots during both analysis periods, the 60 unique hot spots had remarkably consistent characteristics. Nearly all (97%) were multilane roadways, with 70% requiring pedestrians to cross five or more lanes. More than three-quarters had speed limits of 30 mph or higher, and 62% had traffic volumes exceeding 25,000 vehicles per day. All had adjacent commercial retail and service land uses, 72% had billboards, and three-quarters were bordered by low-income neighborhoods. Corridors with these characteristics clearly have the potential to produce high numbers of pedestrian fatalities. We also used hierarchical clustering to classify the hot spots based on their roadway and surrounding landuse characteristics into three types: regional highways, urban primary arterial roadways, and New York City thoroughfares. Each context may require different safety strategies. Our results support a systemic approach to improve pedestrian safety: Agencies should identify other roadway corridors with similar characteristics throughout the US and take actions to reduce the risk of future pedestrian fatalities.

Targeting Fatal Traffic Collision Risk from Prior Non-Fatal Collisions in Toronto

Research questionHow accurately can all locations of 44 fatal collisions in 1 year be forecasted across 1403 micro-areas in Toronto, based upon locations of all 1482 non-fatal collisions in the preceding 4 years?DataAll 1482 non-fatal traffic collisions from 2008 through 2011 and all 44 fatal traffic collisions in 2012 in the City of Toronto, Ontario, were geocoded from public records to 1403 micro-areas called ‘hexagonal tessellations’.MethodsThe total number of non-fatal traffic collisions in Period 1 (2008 through 2011) was summed within each micro-area. The areas were then classified into seven categories of frequency of non-fatal collisions: 0, 1, 2, 3, 4, 5, and 6 or more. We then divided the number of micro-areas in each category in Period 1 into the total number of fatal traffic collisions in each category in Period 2 (2012). The sensitivity and specificity of forecasting fatal collision risk based on prior non-fatal collisions were then calculated for five different targeting strategies.FindingsThe micro-locations of 70.5% of fatal collisions in Period 2 had experienced at least 1 non-fatal collision in Period 1. In micro-areas that had zero non-fatal collisions during Period 1, only 1.7% had a fatal collision in Period 2. Across all areas, the probability of a fatal collision in the area during Period 2 increased with the number of non-fatal collisions in Period 1, with 6 or more non-fatal collisions in Period 1 yielding a risk of fatal collision in Period 2 that was 8.7 times higher than in areas with no non-fatal collisions. This pattern is evidence that targeting 25% of micro-areas effectively could cut total traffic fatalities in a given year by up to 50%.ConclusionHighly elevated risks of traffic fatalities can be forecasted based on prior non-fatal collisions, targeting a smaller portion of the city for more concentrated investment in saving lives.

Pedestrian Crash Analysis: Urban and Rural Areas in Louisiana

Pedestrian safety remains a crucial issue, considering that pedestrian fatalities are increasing faster than motorist fatalities. In 2016, pedestrian fatalities reached nearly 6000 in the United States, which is the highest annual record of pedestrian traffic fatalities in more than two decades. In Louisiana, pedestrian fatalities reached 110 in 2015, nearly 15% of total traffic fatalities. In the same year, the pedestrian fatality rate per 100, 000 populations in Louisiana reached a higher level (2.18) than the national average (1.67). While pedestrian crashes most frequently occur in urban areas, the fatal pedestrian crash rate is 1.5 in urban areas and 3.8 in rural areas, and the rural population is only 26.8%. To reduce pedestrian crashes, this paper presents an analysis of Louisiana pedestrian crashes (2006-2015) and investigates the pedestrian safety problem. In addition, the statistical relationship between pedestrian injury severity and contributing factors, including demographics, pedestrian behavior, and the built environment for urban and rural areas, is established using multinomial logit models. Fatal and severe crashes are strongly related to the alcohol or drug use and elderly age of pedestrians, regardless of their urban or rural locations. However, the pedestrian crashes in urban and rural areas have different characteristics. Variables such as pedestrian crossing/entering road away from intersections, walking in the roadway, dark-unlighted conditions, and speed limits greater than 60 mph are significant only in rural areas but not in urban areas. The findings of this study demonstrate some unique characteristics of Louisiana pedestrian crashes, which can help select the targeted countermeasures.

Pedestrian crash analysis with latent class clustering method

Pedestrians are the most vulnerable users of the highway transportation system. While encouraging “Green Transportation”, a concerning fact emerges in the United States: pedestrian deaths are climbing faster than motorist fatalities, reaching nearly 6000 in 2016 - the highest in over two decades. In 2015, pedestrian fatalities reached 110, 14.6% of total traffic fatalities in Louisiana for that year. Consequently, the Louisiana pedestrian fatality rate (fatalities per 100,000 population) was 2.18, exceeding the U.S. average of 1.67. In an effort to effectively reduce the pedestrian crashes, this paper investigates this problem for Louisiana. However, with the heterogeneity of provided crash data, it is difficult to identify major causation that contribute to these crashes. This study will reveal the findings of the Latent Class Cluster (LCC) model, utilizing it as a preliminary tool for the segmentation of 14,236 pedestrian crashes in Louisiana, between the years of 2006–2015. Next, Multinomial Logit (MNL) models are used to identify the main factors in pedestrian crash severity, shown in the original dataset, by further analyzing the clusters previously obtained by the LCC model. The results shed lights on the crash characteristics that are not apparent without these combined data analysis methods. Certain variables that have not been identified as significant in whole data analysis are identified as significant for a specific cluster, such as pedestrian crossing and entering roads, crash hours between midnight to 6 pm, dark-unlighted conditions, dark-lighted conditions, and non-intersection locations. The study suggests that the LCC regression approach can reveal important, formerly hidden relationships in traffic safety analyses.

Association of Graduated Driver Licensing With Driver, Non-Driver, and Total Fatalities Among Adolescents.

Graduated driver licensing systems typically require an extended learner permit phase, and create night-time driving or passenger restrictions for adolescent drivers. Restricted driving might increase the use of alternative transportation to replace driving and consequently increase crashes and injuries for passengers, bus riders, pedestrians, and bicyclists. This study examined whether graduated driver licensing increases non-driver fatalities among adolescents, and whether it reduces total traffic fatalities combining drivers and non-drivers. Longitudinal analyses were conducted using data from the 1995-2012 U.S. Fatality Analysis Reporting System. Adjusted rate ratios were estimated for being fatally injured in a crash according to: (1) presence/absence of a graduated driver licensing system; and (2) four levels of graduated driver licensing systems (absent, weak, medium, strong). Analyses were conducted in 2015. Among adolescents aged 16 years, graduated driver licensing was not associated with increased passenger fatalities (adjusted rate ratio, 0.96; 95% CI=0.90, 1.03) or pedestrian and bicyclist fatalities (adjusted rate ratio, 1.09; 95% CI=0.85, 1.39), but was associated with an 11% reduction in total traffic fatalities. Among those aged 17 years, graduated driver licensing was not associated with increased fatalities as passengers, pedestrians, or bicyclists, and was not associated with reduced total traffic fatalities. In general, graduated driver licensing systems were not associated with increased fatalities as passengers, pedestrians, bicyclists, and bus riders. Graduated driver licensing systems were associated with reduced total fatalities of adolescents aged 16 years.

Are there higher pedestrian fatalities in larger cities?: A scaling analysis of 115 to 161 largest cities in the United States

ABSTRACTObjective: In 2012, 4,743 pedestrians were killed in the United States, representing 14% of total traffic fatalities. The number of pedestrians injured was higher at 76,000. Therefore, 36 out of 52 of the largest cities in the United States have adopted a citywide target of reducing pedestrian fatalities. The number of cities adopting the reduction goal during 2011 and 2012 increased rapidly with 8 more cities. We examined the scaling relationship of pedestrian fatality counts as a function of the population size of 115 to 161 large U.S. cities during the period of 1994 to 2011. We also examined the scaling relationship of nonpedestrian and total traffic fatality counts as a function of the population size.Methods: For the data source of fatality measures we used Traffic Safety Facts Fatality Analysis Reporting System/General Estimates System annual reports published each year from 1994 to 2011 by the NHTSA. Using the data source we conducted both annual cross-sectional and panel data bivariate and multivariate regression models. In the construction of the estimated functional relationship between traffic fatality measures and various factors, we used the simple power function for urban scaling used by Bettencourt et al. (2007, 2010) and the refined STIRPAT (stochastic impacts by regression on population, affluence, and technology) model used in Dietz and Rosa (1994, 1997) and York et al. (2003).Results: We found that the scaling relationship display diseconomies of scale or sublinear for pedestrian fatalities. However, the relationship displays a superlinear relationship in case of nonpedestrian fatalities. The scaling relationship for total traffic fatality counts display a nearly linear pattern. When the relationship was examined by the 4 subgroups of cities with different population sizes, the most pronounced sublinear scaling relationships for all 3 types of fatality counts was discovered for the subgroup of megacities with a population of more than 1 million.Conclusions: The scaling patterns of traffic fatalities of subgroups of cities depend on population sizes of the cities in subgroups. In particular, 9 megacities with populations of more than 1 million are significantly different from the remaining cities and should be viewed as a totally separate group. Thus, analysis of the patterns of traffic fatalities needs to be conducted within the group of megacities separately from the other cities with smaller population sizes for devising prevention policies to reduce traffic fatalities in both megacities and smaller cities.

A study on crossing speed profiles of pedestrians at signalized crosswalks

Pedestrian–vehicle conflicts are one of the most important safety concerns especially at intersections. Of total traffic fatalities, 30% and 36% are pedestrians in Qatar and in Japan, respectively (National Police Agency in Japan, 2015). Although pedestrians at signalized intersections are given priority during the green phase, turning vehicles in conflict often do not give the right of way to pedestrians but tend to compete for it. Furthermore, long crosswalks, short green times, and other reasons may cause pedestrians to rush or suddenly change their speed without paying attention to the surrounding conditions (Iryo-Asano et al. 2014). The sudden changes in pedestrian behavior while crossing cannot be predicted by the driver, which can cause severe conflicts. Therefore, the possible behavioral changes of pedestrians should be studied so that surrogate safety measures such as post-encroachment time can be quantitatively estimated to provide a reliable assessment of pedestrian–vehicle conflicts and their severities. Continuous pedestrian speed profiles were analyzed at signalized crosswalks considering the impact of crosswalk geometry and signal timing. Five signalized crosswalks at three intersections in Nagoya City were videotaped and individual pedestrian maneuvers were extracted by image processing. A stepwise speed function is proposed to identify significant sudden changes in individual pedestrian speed profiles. The locations and timings of these sudden speed change events were analyzed, and the influencing factors were statistically evaluated. Empirical analysis showed that sudden acceleration events were observed at the entrance points to the pedestrian–vehicle conflict area, which highlights the significance of these events to pedestrian–vehicle conflict analysis. More than a quarter of all acceleration events occurred just after the onset of the pedestrian flashing green signal indication. Furthermore, it is concluded that long crosswalks have higher percentage of speed change occurrence and as a result higher risk of crashes. In this regard, the application of two-stage pedestrian crossing is a potential solution to reduce crosswalk length and the possibility of having unpredicted pedestrian behavioral changes. In general, the results implied that pedestrian entering speed to crosswalk, necessary speed to finish crossing before the onset of the pedestrian red signal indication, and crosswalk length have a significant impact on pedestrian speed change choices.

Road Safety Conditions and Estimated Economic Cost of Traffic Fatalities in Medium-Size Colombian Cities

The Colombia Ministry of Transport, by Resolution 001282 of March 30, 2012, adopted the National Road Safety Plan 2011–2016, which consists of five lines of action, including institutional aspects, strategies on human behavior, strategies on motor vehicles, strategies on road infrastructure, and the attention and rehabilitation system of victims of traffic accidents, for achieving national objectives. In late 2012, the national government (through the Ministry of Transport) subscribed agreements with 10 medium-size Colombian cities to advance their local road safety plans. These 10 cities are among the 25 cities with the highest crash fatality rates per 100,000 inhabitants. The paper presents an overview of the safety conditions in the study cities, which included valuable input provided by the Municipal Road Safety Committee, coupled with data collected in field inspections, spatial analysis, and a review of secondary data sources. This analysis shows that motorcyclists are the most vulnerable road users, followed by pedestrians and cyclists. These road users accounted for between 57.7% and 98.5% of the total traffic fatalities in 2011. This statistic suggests the urgent need for government policies and actions to protect the lives of the most vulnerable road users. The investment of the cities in road safety and related projects is low compared with their gross domestic product and crash fatality costs. This analysis indicates that an effective traffic fine collection system would provide the cities with the money they need to increase their annual investment on road safety projects by 50%, 100%, or even 200%.

Attention and search conspicuity of motorcycles as a function of their visual context

Background Over the years, PTWs’ number of accidents have increased dramatically and have accounted for a high percentage of the total traffic fatalities. The majority of those accidents occur in daylight, clear weather, and at light to moderate traffic conditions. The current study included two experiments. The first experiment evaluated the influence of PTW attention conspicuity on the ability of un-alerted viewers to detect it, whereas the second experiment evaluated the PTWs search conspicuity to alerted viewers. The independent variables in both experiments included driving scenarios (urban and inter-urban), PTW rider's outfit (black, white, and reflective) and PTW distance from the viewer. Method 66 students participated in experiment 1. Every participant was presented with a series of pictures and was asked to report all the vehicle types present in each picture. Experiment 2 included 64 participants and incorporated the same pictures as experiment 1. However, in this experiment the participants were instructed to search the pictures for a PTW and to report its presence or absence as soon as they reach a decision. Results In experiment 1 the detection of a PTW depended on the interaction between its distance from the viewer, the driving scenario and PTW rider's outfit. For an un-alerted viewer when the PTW was distant the different outfit conditions affected its’ attention conspicuity. In urban roads, where the background surrounding the PTW was more complex and multi-colored, the reflective and white outfits increased its attention conspicuity compared to the black outfit condition. In contrast, in inter-urban roads, where the background was solely a bright sky, the black outfit provided an advantage for the PTW detectability. In experiment 2, the average PTW detection rate of the alerted viewers was very high and the average reaction time to identify the presence of a PTW was the shortest in the inter-urban environment. Similar to the results of experiment 1, in urban environments the reflective and white clothing provided an advantage to the detection of the PTW, while in the inter-urban environment the black outfit presented an advantage. Comparing the results of the two experiments revealed that at the farthest distance, the increased awareness in the search conspicuity detection rates were three times higher than in the attention conspicuity. Conclusions The conspicuity of a PTW can be increased by using an appropriate rider's outfit that distinguishes him/her from the background scenery. Thus, PTW riders can actively increase their conspicuity by taking into account the driving route (crowded urban/inter urban), eventually increasing the probability of being detected by the other road users. In addition, increasing the alertness and expectancy of drivers to the presence of PTWs can increase their search conspicuity.

Helmet use and motorcycle fatalities in Taiwan

Motorcycle deaths accounted for more than half of total traffic fatalities in Taiwan in 2002. This study uses the police-reported crash data from Taiwan between 1999 and 2001 to estimate the effectiveness of helmets, simultaneously taking into account of sample selection bias. Sample selection arises because helmet usage will affect the probability of death or injury, which in turn influences whether a crash is included in the data. The results show that sample selection does not seriously bias the estimate of helmet effectiveness and helmets reduce the probability of death in a crash by 40%, which is higher than what was previously found. Without helmets, the number of motorcyclists killed in 2001 would have jumped by 51%. The estimated proportion of helmeted motorcyclists has increased from 71 to 78% between 1999 and 2001, suggesting that helmet use is rising after the implementation of mandatory helmet law in 1997. Also, helmets significantly reduce the likelihood of head and neck injuries in a crash by 53%, and lead to a 71% reduction in the probability of death caused by head and neck injuries.

Pedestrian Accidents: Repeating Patterns and Litigation

Human factors analysis can be applied to pedestrian safety, but pedestrian fatalities have continued to be about 15 percent of the total traffic fatalities, many involving litigation. In some cases, pedestrian behavior is the only part of the situation that is likely to be manipulate. Fatalities are more likely at night. It does not seem likely that effective countermeasures will be introduced in the driver or the visibility environment in the near future. Efforts to encourage safe practices in walking and crossing patterns have been made with marginal effects. Litigation should recognize that drivers cannot avoid every pedestrian. The only practical approach seems to be to modify the visibility and behavior of each pedestrian. A concerted program to make every pedestrian visible by devising, distributing, and enforcing use of visibility aids seems promising. Efforts to implement such visibility improvements would recruit every agency that contacts the walking public, especially the young, old, and those using wheelchairs, bicycles, and other mobility aids.