The United States faces a major challenge in improving the traffic safety performance of our road and street network. An evaluation of historical traffic crash data shows that while substantial improvements in roadway safety have been made in the United States, especially within the last decade, the most recent data show a reversal in this trend with substantial increases in fatalities in both 2015 and 2016 from the previous several years. A review of recent data found that: • Among developed nations, the United States ranks nearly last in terms of annual traffic fatalities per 100,000 population. • A total of 35,092 people died, and hundreds of thousands more were seriously injured, in traffic crashes on roads and streets in the United States during 2015. • The economic impact of crashes in the United States in 2010 was $242 billion in costs related to medical care, emergency services, legal and court issues, insurance administration, congestion, property damage and lost wages–this was roughly equivalent to 1.6 percent of the U.S. Gross Domestic Product (GDP). This cost increased to $836 billion when quality of life considerations are taken into account. • From 1949 to 2014, the fatality rate fell from 7.13 to 1.08 fatalities per 100 million vehicle-miles of travel, even as Americans drove more and more miles. The number of traffic-related fatalities fell from a peak of 54,500 in 1972 to a low of 32,675 in 2014. However, fatalities increased by 7 percent in 2015, and were on trend for a similar increase in 2016. A renewed focus is needed in roadway safety in the United States. Improvements will be needed in every area, including infrastructure, driver education, traffic law enforcement, emergency medical services, and vehicle safety technology. Highway infrastructure investments, in particular, must play a prominent role in our national strategy to decrease traffic fatalities and serious injuries. Highway infrastructure improvements have the potential to reduce both the likelihood and consequences of crashes caused not only by the roadway environment but also by driver error. Improvements to highway infrastructure features, including the roadway, roadside, and traffic control devices, can constrain driver behavior even without the need for a conscious decision by drivers to behave differently. In addition, infrastructure improvements may provide the most certain approach to reducing fatalities and serious injuries because many have been widely implemented, providing years of performance data and allowing researchers to quantify their typical or average effects on safety. In fact, the expected safety benefits of many infrastructure treatments have been cataloged in many sources, including the AASHTO Highway Safety Manual and the FHWA CMF Clearinghouse. Methodologies for incorporating these safety benefits into the planning and design processes are implemented in safety prediction tools, such as the U.S. Road Assessment Program (usRAP) software for developing safer roads investment plans, ViDA. The report documents recent U.S. research on the effectiveness of infrastructure improvements in reducing crash frequency and/or severity. Seven case studies of actual infrastructure improvement projects are presented to illustrate the crash reduction benefits that can be attained by highway agency action. The research team was able to estimate the nationwide infrastructure safety improvement needs, and the potential benefits of addressing those needs, for several roadway types using safer roads investment plans developed for over 12,000 mi of roads and streets in the United States as part of usRAP. Specifically, sufficient data were available for the following roadway types to include them in the assessment of needs and potential benefits: • Rural two-lane undivided roads • Rural four-lane undivided roads • Rural four-lane divided roads • Rural four-lane freeways • Rural six-or-more-lane freeways • Urban two-lane undivided streets • Urban four-lane undivided streets • Urban six-or-more-lane undivided streets • Urban one-way streets • Urban four-lane divided roads and streets • Urban six-or-more-lane divided roads and streets • Urban four-lane freeways • Urban six-lane freeways • Urban eight-or-more-lane freeways The roadways in the usRAP studies were representative of the following functional classes of roadways: • Rural major and minor collectors • Rural minor and principal arterials • Rural freeways • Urban principal arterials • Urban freeways Only paved roads and streets were considered. The National Highway Traffic Safety Administration (NHTSA) Fatality Analysis Reporting System (FARS) database indicates that approximately 64 percent of traffic fatalities in the United States occur on roadways of the roadway types and functional classes considered in the study. This indicates that the estimates of highway infrastructure needs described in this study are conservative. If usRAP study data had been available for a broader range of road types and functional classes, larger estimates of highway infrastructure improvement needs would likely have been obtained. Nationwide needs for highway infrastructure improvements were estimated by scaling up the usRAP safer roads investment plans developed for the 12,000 mi of roads and streets to the national level. It was assumed that the usRAP safer roads investment plans for any given combination of roadway type and traffic volume level were representative of improvement needs for all roads of that roadway type and traffic volume levels within the functional classes studied. Cost-effective infrastructure investments (i.e., those for which the benefits exceed the costs) represent an opportunity to improve safety on U.S. highways and streets. This report makes a conservative estimate of such current infrastructure improvement needs. The estimates developed in this report indicate that current infrastructure improvement needs in the U.S. for the roadway types and functional classes listed above would cost $146 billion to address. If all of these needs were addressed, the present value of the 20- year safety benefits would be $348 billion, with a benefit-cost ratio of 2.4. In other words, benefits of $2.40 could be achieved for every $1.00 spent on infrastructure improvement. Addressing these needs could reduce 63,700 fatalities and more than 350,000 serious injuries over 20 years. The improvements considered in the safer roads investment plans include: • Adding passing lanes • Widening lanes • Widening shoulders • Widening the cross section to include a median • Adding a center two-way left-turn lane • Adding median barrier • Improving the roadside by clearing roadside objects, improving sideslopes, or installing barriers • Installing centerline or shoulder rumble strips • Adding a bicycle lane or path • Adding pedestrian facilities (refuge island, marked crossings) • Improving delineation • Adding intersection left-turn lanes • Converting an intersection to a roundabout • Providing grade separation at an intersection • Signalizing an intersection • Updating rail crossings Most of the improvements were assigned a service life of 20 years. A few of the improvements, including improving delineation and adding rumble strips, have been assigned a service life of 5 years. The investments would need to be repeated every 5 years to maintain the benefits over a full 20-year period. The initial investment to obtain the benefits of this program would be $134 billion with further investments of $6 billion every 5 years to maintain the improved delineation and rumble strips in place. The investment level of $146 billion presented above is the present value of the initial investment of $134 billion plus three $6 billion investments at 5, 10, and 15 years into the program. It should be emphasized that while the benefits of the improvement program would persist over (at least) 20 years, the identified needs exist now and most of the investment is needed now. The scale of these infrastructure improvement needs is large, but so is the scale of the traffic safety challenge to be met in the United States. Meeting the $146 billion in current infrastructure improvement needs would still reduce only 16 percent of the expected fatalities and 12 percent of the expected injuries on the roads evaluated. Given the limitations on the funds available for infrastructure investments for safety improvement, most highway agencies have preferred to focus on investments with the greatest return. As we demand higher benefit-cost ratios from our investments, both the funds needed and the benefits derived from the investment programs become smaller. If we focused only on investments with benefit cost ratios of at least 2.0, as some highway agencies prefer, the size of the infrastructure investment program would be reduced to $64 billion and the benefits of the program would be reduced by 22 percent. If we focused only on investments with benefit-cost ratios of at least 5.0, the infrastructure improvement program would be only $16 billion (i.e., just 9 percent of the $146 billion in needs noted above), but the benefits of the improvement program would be cut almost in half. Thus, a smaller improvement program would be more efficient, but would accomplish only about half as much in reducing fatalities and serious injuries. Six categories of countermeasures collectively will provide nearly 95 percent of the anticipated crash reduction from the infrastructure investment program. The safety needs and benefits assessment found that: • Almost 30 percent of the overall fatality and serious injury reduction could come from intersection improvements. The intersection improvement with the greatest potential for fatality and serious injury reduction is conversion of existing intersections to roundabouts. • Nearly 20 percent of the overall reduction in fatalities and serious injuries could come from roadside improvements. The analysis results indicate that installing roadside barriers should constitute the largest component of the improvement program, while clearing roadside objects would have the highest benefit-cost ratio. • Nearly 20 percent of the fatality and serious injury reduction could come from the addition or improvement of pedestrian facilities. The analysis results show that most of these improvements would come from providing sidewalks where none currently exist, but addition or improvement of signalized and unsignalized pedestrian crossings should also be an element of the infrastructure improvement program. • About 14 percent of the overall benefits of the recommended infrastructure investment program could come from installation of median barriers on existing divided highways. • Nearly 9 percent of the overall benefits of the recommended infrastructure investment program could come from rumble strips. The analysis indicates that shoulder rumble strips are needed at the most locations, but centerline rumble strips can have key benefits on undivided roadways. The need for centerline rumble strips may even be underestimated in the analysis results. • Finally, nearly 3 percent of the overall benefits could come from shoulder paving and widening. Current investments in highway infrastructure improvements in the U.S. are substantially lower than the identified needs. There are no comprehensive data on how much U.S. highway agencies currently spend on traffic safety improvements. FHWA provides approximately $2 billion annually to state and local agencies in the Highway Safety Improvement Program (HSIP). State and local governments also invest funds of their own in safety improvement projects, although no national estimates of state and local government expenditures on traffic safety are available. In addition, general highway improvement programs make many improvements that benefit safety as well as meeting other objectives. However, even if, as a nation, we are spending $4 or $5 billion on infrastructure improvements for safety, this is only a small portion of the identified needs. Highway infrastructure improvements can serve an important role in moving Toward Zero Deaths, but infrastructure improvement programs must begin to address a much greater portion of the identified needs. The $146 billion in identified needs do not necessarily all need to be addressed in the first year of an investment program, but these needed investments should not be deferred too long because new needs develop each year. If we continue to underinvest in infrastructure improvement, the backlog of unaddressed needs will grow rather than shrink. (Author/publisher)
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