The focus on innovation across state departments of transportation (DOTs) continues to grow and strengthen. Unlike research activities, which have established programs and processes, innovation programs are relatively new. DOTs are focusing more directly on innovation, including that related to internal organizational excellence and external program and project development and delivery. NCHRP Synt...

State departments of transportation (DOTs) must develop long-range transportation plans (LRTPs) and State Transportation Improvement Programs (STIPs) as key products of the transportation planning process. DOTs have a long history of developing these documents through many cycles of planning. NCHRP Synthesis 631: Integrating Performance-Based Planning into Long-Range Transportation Plans and STIPs...

Per- and polyfluoroalkyl substances (PFAS) are a class of more than 6,000 contaminants of emerging concern that can harm both ecosystems and human health. These anthropogenic compounds contain carbon–fluorine bonds that make them stable and persistent in the environment, earning them the nickname “forever chemicals.” NCHRP Synthesis 630: Practices to Identify and Mitigate PFAS Impacts on Highway C...

State departments of transportation (DOTs) face considerable challenges in implementing, enhancing, or replacing their existing maintenance management systems (MMSs). These processes are not only expensive and time-consuming but also involve considerable risk, because these systems have usually been in place for many years. NCHRP Synthesis 629: Practices for Capturing and Integrating Cost Data in ...

Some state departments of transportation (DOTs) have begun to track data pertaining to ancillary assets (that is, assets other than pavements and bridges) in their Transportation Asset Management Plans. However, most DOTs do not track this information, even though they inventory and manage many of these ancillary assets. NCHRP Synthesis 628: Ancillary Asset Data Stewardship and Models , from TRB's...

Water infiltration is a common problem in tunnels. Such infiltration accelerates the deterioration of the structure and elements within and creates hazards in the form of icicles and slippery roadways. The severity of water infiltration often reflects various factors, so determining the appropriate remedy is challenging and frequently requires an extensive investigation to understand the source an...

State departments of transportation (DOTs) are required by federal law to coordinate transportation planning and programming processes with metropolitan planning organizations (MPOs) in the state. However, state DOTs and MPOs have varying coordination practices depending on their specific contexts. NCHRP Synthesis 626: Practices for Statewide and MPO Coordination , from TRB's National Cooperative ...

Alternative contracting methods (ACMs), including design-build, construction manager/general contractor, and public-private partnerships have added a wide range of options for state departments of transportation (DOTs) to consider when delivering projects. NCHRP Synthesis 625: Programmatic Implementation of Alternative Contracting Methods , from TRB's National Cooperative Highway Research Program,...

Many state departments of transportation (DOTs) are undergoing organizational changes to address climate change. Changes range from hiring additional staff to creating new offices within the organizational structure of the agency. State requirements in the form of legislation, executive orders, and climate action plans are primary drivers for state DOT involvement with climate change. NCHRP Synthe...

State transportation agencies have many tools available with which to maintain pavements proactively. These include tools such as pavement management systems to track roadway conditions and life cycle cost analysis tools. NCHRP Synthesis 623: Wintertime Pavement Maintenance Practices , from TRB's National Cooperative Highway Research Program, documents the current state DOT practices for the react...

Alternative contracting methods (ACMs) capture the delivery methods that are not design-bid-build (D-B-B), low bid, or traditional federal aid. Common ACMs used by state departments of transportation (DOTs) include design-build (D-B), construction manager/general contractor (CM/GC), progressive design-build (P-D-B), public-private partnerships (P3), and indefinite delivery/indefinite quantity (IDI...

Many state departments of transportation (DOTs) build and operate escape ramps to allow heavy trucks that cannot maintain safe speeds on steep downgrades to safely exit the highway instead of losing control and crashing. Some escape ramps use upward-sloping beds of loose aggregate to slow the vehicles, while others employ passive or active mechanical devices such as cables to slow the vehicles. So...

The design of bridges often involves the use of structural analysis models of varying degrees of complexity. A variety of analysis methods and software can be used to create and analyze these models, and the process can be quite complex, with significant amounts of input and output data. Quality assurance and quality control are two essential processes. NCHRP Synthesis 620: Quality Processes for B...

State departments of transportation undertake hundreds of construction projects each year that affect, and are affected by, streams and rivers. These projects include replacement and rehabilitation of bridges and culverts, as well as new construction and rehabilitation of highways in stream corridors. While the hydraulic design standards for the completed bridge, culvert, or highway are well estab...

Women comprise only 15 percent of the transportation workforce, and this statistic declines in executive and leadership positions and does not reflect those who may not identify as men or women. For women of color, the numbers are even more disparate. NCHRP Synthesis 618: Advancing Gender Equity in the DOT Workforce , from TRB's National Cooperative Highway Research Program, documents current stat...

Surficial slope failures in highway fill embankments are shallow landslides that occur within the embankment fill, usually affecting only a portion of the slope’s height. These failures tend to occur after a vulnerable embankment slope is subjected to a triggering event. An embankment’s failure susceptibility generally depends on factors such as slope steepness, material composition, and ability t...

The construction, maintenance, and operation of transportation infrastructure requires immense amounts of products and materials. New products, materials, engineered systems, and innovative technologies are presented to state departments of transportation (DOTs) by suppliers and manufacturers, as well as sometimes by contractors and internal DOT staff. NCHRP Synthesis 616: State DOT Product Evalua...

One tool utilized by some departments of transportation (DOTs) to improve safety performance is conducting road safety audits (RSAs), also known as “road safety assessments.” An RSA is a formal evaluation of the safety performance of an existing or future highway segment or intersection performed by an independent, multidisciplinary team. NCHRP Synthesis 615: DOT Practices on Road Safety Audits , ...

Post-construction stormwater best management practices (BMPs) are designed to reduce the amount of stormwater runoff, prevent erosion, and improve water quality by removing pollutants from stormwater. NCHRP Synthesis 614: Outsourcing Post-Construction Stormwater Best Management Practice Inspection and Maintenance Activities , from TRB's National Cooperative Highway Research Program, documents stat...

Contrast pavement markings (CPM) improve the visibility of pavement markings by providing better contrast with the pavement surface, especially on lighter-colored pavements. NCHRP Synthesis 613: Contrast Pavement Markings Practices , from TRB's National Cooperative Highway Research Program, documents current CPM practice by state departments of transportation.