REVIEW OF PRACTICES TO IMPLEMENT COST-EFFECTIVE ROADWAY SAFETY INFRASTRUCTURE IMPROVEMENTS TO REDUCE THE NUMBER AND SEVERITY OF CRASHES INVOLVING COMMERCIAL MOTOR VEHICLES

Chapter Five. Challenges and Conclusions

Factors Affecting CMV Safety

This report identifies safety infrastructure improvements and practices that are being deployed and show promise for improving CMV safety outcomes. The future of CMV safety may also be affected by a number of unpredictable trends:

• How freight economics and traffic will interact.
• How infrastructure safety improvements and transportation technology may change CMV safety.
• How freight planning and highway safety planning will respond to these trends.

Economic Trends

The following changes in freight demand and in trucking industry capacity are expected in the near term (1 to 3 years):

• VMT increase. As crude oil prices have declined, so too have motor fuel prices. This trend has resulted in VMT increases that resume the growth trends before the Great Recession. This means trucks will be competing with more cars on the road.
• Truck VMT growth. The National Strategic Freight Plan and many State-level freight mobility plans are estimating significant long-term growth in freight demand as the economy and population grow.⁽⁷⁾ The DOT estimates that freight tonnage moving on the Nation's transportation network will grow 40 percent in the next three decades, and the value of the freight will almost double.⁽⁷⁸⁾ This means more truck traffic can be expected to join the growing numbers of vehicles on the road.
• Constrained trucking industry capacity. The trucking industry has been wary of a significant anticipated truck driver shortage with an estimated need to fill over 2 million jobs between 2012 and 2022, fueled by changing employment demographics.⁽⁷⁹⁾ New regulations (hours of service and electronic log books⁽⁸⁰⁾) add a degree of uncertainty to the scope of this short-term issue. In addition, weak freight volumes in the recent past have led to increasing bankruptcies among smaller firms, resulting in reductions in new truck equipment orders.⁽⁸¹⁾ When the economic recovery strengthens, the ability of the motor carrier industry to respond may be limited in the near term. Driver turnover and longer use of older equipment could lead to adverse CMV safety outcomes.
• Persistent traffic congestion. Even before the passage of the FAST Act, many States were taking steps to increase transportation revenues to address network maintenance issues and relieve congestion chokepoints. Even with these new financial resources, States can be expected to struggle with stubborn congestion in urban areas. Much of this congestion will be difficult to resolve with capacity expansion because of available resources, land use conflicts, and environmental issues.

As FHWA works with States to conduct the freight planning required by the FAST Act and updates its own national strategic freight plans, FHWA can help States adopt scenario plans for these and other changes in CMV traffic that will be critical to inform State SHSPs and financially constrained freight project plans.

Changes in highway financing could also affect truck VMT and industry capacity. Many States have been experimenting with road user fees, which are highway funding mechanisms to replace or augment motor fuel taxes and vehicle registration fees. Tests of such systems have been encouraged in previous surface transportation reauthorizations, and section 6020 of the FAST Act also establishes a grant program to assist States in testing user-based alternative revenue mechanisms. Since combination trucks travel more miles per vehicle than autos or single-unit trucks, any user-based fee is likely to charge large trucks more, as is already the case with per-gallon motor fuel taxes. If new user-based alternative funding mechanisms increase the relative share of user fees paid by CMVs, the economics of longer-distance truck trips may change. This could lead to either pressure for longer combination vehicles to gain more productivity from mileage-based fees assessed on the tractor unit or more truck-to-rail diversion of intercity trips Either of these outcomes could have implications for CMV safety.

Potential Future Safety Practices

This report has described a number of roadway infrastructure safety improvements, but some incremental adjustments could increase their safety benefits. The following examples of possible alterations to current practices could be explored with existing or new technologies:

• Exclusive CMV lanes. This would be a lower-cost variant of the exclusive truck roadway described in chapter two, where the inner lane or lanes would be designated and marked for usage only by CMVs, but not separated with additional space and barrier. Unlike the truck lane restrictions described in chapter four, positioning the large vehicles on the inner lanes reduces the inefficiency and safety issues associated with the interaction of large vehicles with merging vehicles. This kind of separation may be worthwhile in certain corridors, and infrastructure improvements could be balanced against advancement in vehicle technology that reduces human error by drivers of automobiles and CMVs.
• Vehicle-specific adaptable advisory speeds. A variation on dynamic speed advisory signs described in chapter three, this could address the lower speeds that are appropriate for vehicles with higher centers of gravity. This may also potentially improve driver respect for advisory speed signing because many small passenger vehicles can safely negotiate curves at speeds significantly higher than the posted advisory speed if they have adequate tires and the pavement is not wet or icy. Similar applications may be appropriate on ramps.
• Active traffic management strategies. Dynamic lane restrictions, opening shoulders for use as travel lanes, and variable speed limits could be deployed at known bottlenecks to prevent or relieve recurring congestion. These strategies could be activated as part of a roadway segment's congestion management strategy, segregating CMV and auto traffic, opening additional "lanes" and adjusting speed limits to address safety concerns if queues build. When traffic volumes ease in the corridor, the larger vehicles could once again be allowed to use all lanes and shoulder driving would no longer be permitted.
• Size-sensitive in-vehicle warnings. Vehicle technologies are currently available that provide proximity alerts. As these systems become even smarter, they may consider additional information about the potential risk by considering the size of other vehicles along with the distance and speed to determine the appropriate safe spacing between vehicles.

Freight and Safety Planning Responses

The subject of CMV safety also raises issues beyond the scope of this report that the transportation safety community can consider as the FAST Act is implemented. Pertinent stakeholders include policy makers, modal administrations in DOT, State infrastructure owners, law enforcement agencies, industry associations, vehicle and traffic safety equipment manufacturers, and transportation research institutions. These safety issues include the following:

Freight and safety planning integration. Congress has authorized the designation of the Primary Highway Freight System and mandated State freight planning after October 2017 that will identify State-specific highway freight networks. Collection of traffic safety data on these corridors could help inform data-driven safety planning at the State level, such as during the SHSP process. In addition, as States identify projects to improve freight operations on these corridors, they should consider safety outcomes on these freight highway networks.

Truck size and weight issues. Section 32801 of the Moving Ahead for Progress in the 21st Century Act required DOT to conduct a comprehensive truck size and weight limits study. The April 2016 report addressed five core technical areas and concluded that data gaps and model limitations prevented a conclusive, bottom-line finding. Without this definitive conclusion, certain shippers and motor carriers have advocated adjustments to the Federal truck size and weight limits (e.g., longer combination vehicles within current weight limits and heavier trucks with different axle configurations) in the FAST Act authorization and annual appropriations deliberations. The CMV safety measures in this report are responsive to the current CMV fleet (even with regional size and weight variations authorized in current law). Changes to truck size and weight restrictions may alter CMV safety outcomes and require different practices.

Findings and Conclusions

Infrastructure will always be critical to the safe and efficient operation of the Nation's highway system The goal of no fatalities cannot be achieved by focusing on infrastructure alone, so Congress requires State SHSPs to address six elements of highway safety as key factors in evaluating highway projects:

• Engineering
• Management
• Operations
• Education
• Enforcement, and
• Emergency services.

States are currently deploying a number of infrastructure safety measures identified with varying degrees of demonstrated effectiveness in addressing CMV safety needs. The safety improvements and practices included are not limited strictly to pavements and bridges but also consider roadside hardware, capacity improvements, signage and markings, better work zones, and ways the infrastructure can support safety enforcement efforts. While standard safety design practices and traffic engineering work well on large portions of the systems, enhanced measures can be used in areas of greater risk. Dynamic signing, higher-performing barriers, and detection systems are examples. Technology is playing a greater part in safety every year as more concepts emerge as practical applications to provide smarter vehicles and smarter infrastructure The countermeasures described in this report fall within the engineering, management, operations, and enforcement elements.

Each State will continue to identify emphasis areas, strategies, and goals through a collaborative planning process with multiple stakeholders. Beginning in 2017, States will also establish annual targets for fatalities and injuries to measure safety performance. The CMV-related emphasis areas are already included in over half of the State SHSPs. Since 12 percent of all traffic fatalities involve large trucks and buses, State data-driven approaches may focus on many other crash and casualty issues and factors. However, with the vision of zero deaths embraced by FHWA and most State DOTs, CMV safety will continue to be part of reaching this goal.

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