Three-dimensional (3D) highway design models serve as a building block for the modern-day digital jobsite. The technology and associated practices leverage digital and geolocated information for more effective planning and construction of transportation projects compared to the traditional two-dimensional design process. With 3D modeling software, design and construction teams can better communicate with stakeholders and among themselves using visualizations where “a 3D picture is worth a thousand words.” Delivery teams can develop, test, and revise project options virtually throughout the design and construction phases before costly and time-consuming problems are encountered in the field. Important project design features can be viewed geospatially from multiple perspectives, and checks can be done to detect design flaws and potential clashes before construction begins.
In addition, 3D model data allows for automation of tasks such as estimating. For construction, the model data can be transferred to automated machine guidance systems that work with global positioning (GPS/GNSS) to improve the operation of construction equipment such as bulldozers, graders, excavators, and pavers. The combination of 3D modeling and GPS machine control helps agencies complete highway projects efficiently with improved quality and safety.
For more information: https://www.fhwa.dot.gov/construction/3d/
Highway agencies are using ABC to significantly decrease the time needed for bridge planning and construction, reducing traffic delays and road closures and lowering project costs. ABC planning and construction methods, designs, and materials can produce safer, more durable bridges with longer service lives than conventional bridges. These technologies include the geosynthetic reinforced soil-integrated bridge system, prefabricated bridge elements and systems, and slide-in bridge construction.
- Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS): GRS-IBS bridges employ a simple design that can be adapted to suit environmental or other needs and modified easily in the field to adjust to unexpected site conditions. Once built, GRS-IBS bridges are durable and easy to maintain. The construction creates a smooth transition from the roadway to the bridge, alleviating the bump normally caused by differential settlement between the bridge abutment and the approaching roadway. Decreasing the impact loads normally caused by the bump reduces maintenance needs. GRS-IBS bridges can be designed for a wide range of loading conditions, such as in seismic areas and rapidly changing water elevations.
For more information: https://www.fhwa.dot.gov/engineering/geotech/
- Prefabricated Bridge Elements and Systems (PBES): PBES are bridge components constructed offsite then brought to the project location, ready to erect. With traditional bridge construction, foundations for piers and abutments must be built first. Pier columns and caps must be built before beams and decks are placed. With PBES, these components can be fabricated concurrently and shipped in as needed. In addition, traditional onsite construction exposes work crews to moving traffic and to working over water or near power lines. Using PBES shortens onsite construction time so that fewer workers need to be exposed to traffic control. It results in durable bridges that can be built faster, more safely, and with fewer traffic delays.
For more information: https://www.fhwa.dot.gov/bridge/abc/
- Slide-In Bridge Construction (SIBC): SIBC is a cost-effective technique for deploying PBES and quickly replacing an existing bridge. A new bridge is built on temporary supports parallel to an existing bridge. During construction, traffic continues uninterrupted on the existing bridge. Once construction is complete, the road is closed temporarily and the existing bridge structure is demolished or slid out of the way. The new bridge is slid into place, tied in to the approaches, and opened to traffic.
For more information: https://www.fhwa.dot.gov/construction/sibc/
Innovative solutions gathered during the procurement process can turn challenging highway projects into more successful ones for both contractors and public agencies. ATCs are frequently used with design-build contracting, but have also been used with traditional design-bid-build (D-B-B) contracts under FHWA’s Special Experimental Projects (SEP) 14 initiative. Incorporating ATCs into the D-B proposal or D-B-B bidding process allows contractors the opportunity to provide agencies with ideas for advancing new technologies and construction methods that can lower costs, reduce risks, increase quality, and accelerate schedules. Some have likened ATCs to value engineering change proposals, which are submitted during procurement rather than after contract award.
During a competitive procurement process with ATCs, companies may propose confidential suggestions for modifying a contract requirement. ATCs offer design and construction options that are equal to or better than the owner’s base design and construction criteria for a project. If the ATC concept is acceptable to the owner, it may be incorporated as part of the proposing D-B team’s technical and price submittal, or a contractor’s traditional bid for D-B-B. By submitting confidential ATCs that support cost and time savings, innovative contractors can gain a competitive edge during the bidding or proposal process. The solicitation of contractors’ ideas during procurement promotes competition that enables agencies to choose design and construction solutions offering the best value to the public.
For more information: https://www.fhwa.dot.gov/construction/cqit/atc.cfm
CM/GC is an alternative contracting method (ACM) used by many State highway agencies to accelerate project delivery and reduce costs and risks for project owners. CM/GC is an ACM to the traditional design-bid-build or design-build (D-B) methods, and it offers certain benefits over those approaches. In CM/GC, the owner hires a contractor to act as a consultant during the design phase (CM). The CM will offer suggestions to the owner’s designer (internal or hired consultant) based on industry experience with innovations, successful construction practices, constructability issues, cost projections, and project schedule. When the owner and the contractor determine enough design is complete and critical risks addressed, the owner will work with the contractor (GC) to establish a price for the construction contract. The owner may bid the project in the open market if an acceptable price cannot be established.
Use of CM/GC offers the potential for lower project costs primarily because risks are identified early in project development before construction begins. The process also encourages the owner and contractor to form a more effective project management team to look at all options, including use of innovative techniques or approaches, to reduce time and cost. The combined knowledge of the owner, designer, and contractor fosters a partnership that can result in improved project designs, greater cost certainty, and optimized construction schedules.
D-B is an alternative contracting method (ACM) for improving project delivery that is now used by the majority of State highway agencies, especially for shortening overall completion time and gaining early “cost certainty.” In D-B, the project owner typically hires a design-build firm, which enhances communication and sharing of expertise between the designer and contractor. Various D-B options are commonly used for public-private partnerships (P3s), where special public and private sector funding can be leveraged to advance important projects or for operations and maintenance. D-B is an ACM to the traditional design-bid-build or construction manager/general contractor (CM/GC) methods, and it offers certain benefits over those approaches. Progressive D-B is an emerging form of D-B that offers an option to the CM/GC ACM.
Using the design-build (D-B) ACM, an agency identifies what it wants constructed, accepts proposals, and selects a D-B team to assume the risk and responsibility for the design and construction phases. Often, alternative technical concepts (ATCs) are solicited by the owner to allow proposers the opportunity to bring innovative ideas to the project’s design or construction that can save money, time, or increase safety. The design and construction phases can be coordinated and overlapped effectively by the team to provide efficiencies and reduce the overall delivery time. The D-B process provides the contractor with flexibility in selecting the design, materials, and construction methods. The contractor also works closely with the designer, sharing expertise to reduce the risk of design errors that can add to project costs and delays. This collaboration between the designer and contractor allows for greater innovation and can improve project quality.
For more information: https://www.fhwa.dot.gov/construction/cqit/desbuild.cfm
Geographic information system (GIS) tools at Federal, State, and local agencies are often housed separately, which can make project coordination challenging. Geospatial data collaboration helps agencies save time on highway projects by making tools, data, and maps available on the Web. This shared access can improve the efficiency of working relationships among agency stakeholders, simplify data distribution among project participants, and enhance or streamline information flow for environmental and other processes. It can also reduce the time required to assemble and manage data, automate repetitive analyses, and improve the quality and timeliness of decision-support documents.
For more information: https://www.gis.fhwa.dot.gov/gdc.aspx
Maintaining the appropriate amount of pavement friction is critical for safe driving. In locations where drivers may brake excessively, for example around curves, on steep grades, and near intersections, the road surface can become prematurely polished due to extensive braking, reducing pavement friction and allowing vehicles to skid when drivers apply their brakes. Wet road surfaces can further reduce pavement friction and cause drivers to lose control, resulting in skidding or hydroplaning. These locations make up a small percentage of U.S. highways, but a high percentage of crashes occur on them.
HFST are high-quality aggregates that can be applied to existing or potential high-crash areas to immediately and dramatically reduce specific crash types and the related injuries and fatalities. HFST restore or maintain pavement friction, helping motorists keep better control in dry and wet driving conditions. While the initial costs are higher than conventional pavement, the long-lasting durability of HFST, combined with its targeted use in critical locations, makes the product a low-cost option over its life cycle.
For more information: https://safety.fhwa.dot.gov/roadway_dept/pavement_friction/high_friction/
The IQED strategy promotes effective practices for simplifying and expediting the development of the National Environmental Policy Act (NEPA) documents required for construction projects. The approach centers on telling the project’s story while keeping the NEPA document brief and ensuring it meets legal requirements. The result is NEPA documents that are more effective at disclosing the information used in making project decisions to the public and participating agencies. This, in turn, helps project proponents accelerate project delivery and achieve better environmental outcomes. It also helps agencies increase efficiency and effectiveness during NEPA document production by reducing the amount of work and resources required. Stakeholders benefit as well from documents that are easier to read and understand.
For more information: https://www.environment.fhwa.dot.gov/nepa/documentation.aspx
Pavement is typically designed to bear traffic for at least 20 years with regularly scheduled maintenance. When pavement begins to crack and crumble prematurely, one potential cause is the pavement and base layer not being compacted properly, and therefore lacking a uniform thickness, during construction. Intelligent compaction (IC) is a modern approach to compacting pavement materials that enhances pavement quality, uniformity, and long-lasting performance.
IC uses vibratory rollers equipped with accelerometers, a continuous measurement system, Global Positioning System-based mapping, and an onboard computer reporting system so operators can monitor the compaction process in real-time and provide corrections if needed. IC rollers compact with greater efficiency with fewer passes than traditional modern vibratory rollers, producing time, cost, and fuel savings. Continued use and improvement of IC technology will produce better quality roadways and allow agencies to operate more efficiently.
For more information: https://www.fhwa.dot.gov/pavement/ic/
Fatal and injury crashes often occur at or near intersections as motorists, pedestrians, and bicyclists cross paths or change direction. Innovative intersection and interchange geometrics can accommodate traffic volumes efficiently while reducing or altering conflict points to allow for safer travel. These effective alternatives to traditional designs include modern roundabouts, diverging diamond interchanges, and intersections with displaced left-turns or variations on U-turns.
- Roundabouts and Mini-Roundabouts: Roundabouts are a type of circular intersection where traffic travels counterclockwise around a center island. Vehicles entering the roundabout yield to traffic already circulating. FHWA has identified roundabouts as a Proven Safety Countermeasure due to their ability to substantially reduce the types of crashes that result in injury or loss of life.
- Diverging Diamond Interchange (DDI): DDIs eliminate the signalized left-turn phase within an interchange by shifting the crossroad traffic to the left side of the roadway between the ramp terminals.
- Displaced Left-Turns (DLT) or Variations on U-Turns: With DLTs, motorists cross opposing lanes at an intersection away from the main intersection. They then travel on a road parallel to the main road until they turn left with the through traffic at the main intersection. Similarly, designs that are variations on U-turns require motorists to make a U-turn maneuver at a one-way median a distance away from the main intersection, rather than a direct left-turn at the main intersection.
For more information: https://safety.fhwa.dot.gov/intersection/
When cities, counties, and other local public agencies (LPAs) use Federal funds for transportation projects, they must follow all of the applicable Federal laws and regulations attached to the Federal aid. State departments of transportation (DOTs) oversee the LPA program and work with agencies to help them use Federal-aid effectively. Many DOTs use one or more of the following strategies to address common challenges with locally administered Federal-aid project delivery:
- Certification and qualification programs. State DOTs can develop certification or qualification programs to verify an LPA is staffed and trained to manage one or more areas of Federal-aid project delivery. This allows DOT staff to focus resources on non-certified LPAs that may need a higher level of assistance.
- Consultant services flexibilities. State DOTs can adopt a variety of practices for using consultant services on local programs and projects. These include establishing procedures to help LPAs procure and manage consultant services effectively, developing contracting options for LPAs, and using consultants at the State level to manage local programs.
- Stakeholder partnering. This form of program-level partnering involves bringing together representatives from a State’s DOT, LPAs, and FHWA division office on one committee that meets regularly to identify and launch training and process improvements in Federal-aid project delivery.
For more information: https://www.fhwa.dot.gov/federalaid/lpa/
Traffic incidents, including crashes, disabled vehicles, and debris on the road, create unsafe driving conditions; put motorist and responder lives at risk; and account for a large percentage of traffic delays. Congestion from incidents can result in secondary crashes, further increasing risk and delays and interrupting freight movement. To help reduce the time it takes to clear traffic incidents, FHWA, in cooperation with the second Strategic Highway Research Program (SHRP2), offered the first national traffic incident management process and training program. This unique training for first responders—including those from police, fire, emergency medical, public safety, and transportation disciplines—focuses on safe, quick clearance at traffic incident scenes that protects motorists and responders while minimizing the impact on traffic flow. FHWA also offers a train-the-trainer course, in cooperation with SHRP2, for equipping experienced responders to train other responders.
For more information: https://ops.fhwa.dot.gov/eto_tim_pse/about/tim.htm
While environmental requirements for transportation projects are typically accomplished on an individual basis, many projects have common components or actions that are appropriate for review at a programmatic level. PAs can streamline the process for handling commonly encountered project actions and types. These interagency agreements set procedures for consultation, review, performance, and compliance with one or more Federal laws and can also address Tribal, State, and local laws. Using PAs, agencies can increase efficiency and provide appropriate consideration for the environment, which leads to better project delivery with enhanced environmental outcomes.
PAs may be developed on a watershed, landscape, ecosystem, State, regional, or national scale. They are part of a larger collection of programmatic approaches (including regional permits, programmatic consultations, landscape-scale approaches, etc.) to environmental process reviews, data collection, and regulatory compliance, including performance standards and adaptive management. FHWA has promoted PAs through initiatives such as EDC, Eco-Logical, and the Red Book and through regular environmental program implementation. PAs have also been promoted through Federal legislation, including the Fixing America’s Surface Transportation Act (FAST Act) Section 1304(k).
For more information: https://www.environment.fhwa.dot.gov/env_initiatives/initiatives_home.aspx