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 reactive pavement maintenance performed during the winter months when flexible and rigid pavements must be repaire...

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. Some agencies use intelligent transportation technologies to detect trucks that are driving at excessive speeds...

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 Bridge Analysis Models , from TRB's National Cooperative Highway Research Program, documents state department ...

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 , from TRB's National Cooperative Highway Research Program, seeks to address the need for more knowledge regard...

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 established, there are elements of risk involved in any temporary occupancy of a waterway for construction, includ...

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 state departments of transportation (DOT) practices related to advancing gender equity in DOT workforces.

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 to withstand adverse drainage conditions. Examples of trigger mechanisms include intense rainfall, snowmelt, s...

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 state department of transportation practices related to outsourcing post-construction stormwater BMP inspection a...

Accurate and timely moisture measurement of soils, aggregates, and recycled materials is critical to properly compacting these materials. There are numerous methods for measuring the moisture content of the soil; some are laboratory-based, and some are done in-situ. NCHRP Synthesis 612: Moisture Measurement for Pavement Foundations and Slopes , from TRB's National Cooperative Highway Research Program, documents state department of transportation (DOT) practices for field and laboratory moisture measureme...

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.