Long-Term Pavement Performance Program, known as LTPP, is a research project supported by Federal Highway Administration (FHWA) to collect and analyze pavement data in the United States and Canada. Currently, the LTPP acquires the largest road performance database. [1] [2]
LTPP program was initiated by the Transportation Research Board (TRB) of the National Research Council (NRC) in the early 1980s. The FHWA with the cooperation of the American Association of State Highway and Transportation Officials (AASHTO) sponsored the program. The program was focusing on examining the deterioration of the nation’s highway and bridge infrastructure system. In the early 1980s, TRB and NRC suggested that a "Strategic Highway Research Program (SHRP)" should be started to concentrate on research and development activities that would majorly contribute to highway transportation improvement. Later in 1986, the detailed programs were published entitled "Strategic Highway Research Program—Research Plans".
The LTPP program collects data from in-service roads and analyzes it as planned by the SHRP. The LTPP aims to understand the possible reasons behind the poor or good performance of pavements. Hence, the effects of different parameters such as weather, maintenance actions, material and traffic on performance are studied. Data is collected in a timely manner, and then analyzed to understand and predict the performance of roads. It is worth to mention that the LTPP program was transferred from SHRP to FHWA in 1992 to continue the work.
LTPP Data is collected by four regional contractors. New data is regularly uploaded to the online platform every six months. The number of the pavement test sections monitored in the LTPP program is more than 2,500. These pavement sections include both asphalt and Portland cement concrete. Road sections are across different states and provinces of the United States and Canada.
The LTPP holds an annual international data analysis contest in collaboration with the ASCE. The participants are supposed to use the LTPP data. [3]
A road surface, or pavement, is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.
Asphalt concrete is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the beginning of the twentieth century. It consists of mineral aggregate bound together with asphalt, laid in layers, and compacted. The process was refined and enhanced by Belgian-American inventor Edward De Smedt.
A dipstick is one of several measurement devices.
Rumble strips are a road safety feature to alert inattentive drivers of potential danger, by causing a tactile vibration and audible rumbling transmitted through the wheels into the vehicle interior. A rumble strip is applied along the direction of travel following an edgeline or centerline, to alert drivers when they drift from their lane. Rumble strips may also be installed in a series across the direction of travel, to warn drivers of a stop or slowdown ahead, or of an approaching danger spot.
The Manual on Uniform Traffic Control Devices for Streets and Highways is a document issued by the Federal Highway Administration (FHWA) of the United States Department of Transportation (USDOT) to specify the standards by which traffic signs, road surface markings, and signals are designed, installed, and used. In the United States, all traffic control devices must legally conform to these standards. The manual is used by state and local agencies as well as private construction firms to ensure that the traffic control devices they use conform to the national standard. While some state agencies have developed their own sets of standards, including their own MUTCDs, these must substantially conform to the federal MUTCD.
The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program and the Federal Lands Highway Program. Its role had previously been performed by the Office of Road Inquiry, Office of Public Roads and the Bureau of Public Roads.
The National Bridge Inventory (NBI) is a database, compiled by the Federal Highway Administration, with information on all bridges and tunnels in the United States that have roads passing above or below. This is similar to the grade crossing identifier number database compiled by the Federal Railroad Administration which identifies all railroad crossings. This bridge information includes the design of the bridge and the dimensions of the usable portion. The data is often used to analyze bridges and judge their conditions. The inventory is developed with the purpose of having a unified database for bridges to ensure the safety of the traveling public as required by the Federal-Aid Highway Act of 1968. It includes identification information, bridge types and specifications, operational conditions, bridge data including geometric data and functional description, and inspection data. Any bridge more than 20 feet long used for vehicular traffic is included.
Annual average daily traffic, abbreviated AADT, is a measure used primarily in transportation planning, transportation engineering and retail location selection. Traditionally, it is the total volume of vehicle traffic of a highway or road for a year divided by 365 days. AADT is a simple, but useful, measurement of how busy the road is.
The pavement condition index (PCI) is a numerical index between 0 and 100, which is used to indicate the general condition of a pavement section. The PCI is widely used in transportation civil engineering and asset management, and many municipalities use it to measure the performance of their road infrastructure and their levels of service. It is a statistical measure and requires manual survey of the pavement. This index was originally developed by the United States Army Corps of Engineers as an airfield pavement rating system, but later modified for roadway pavements and standardized by the ASTM. The surveying processes and calculation methods have been documented and standardized by ASTM for both roads and airport pavements:
Pavement management is the process of planning the maintenance and repair of a network of roadways or other paved facilities in order to optimize pavement conditions over the entire network.
Francis Bernard Francois was an American engineer and lawyer who received recognition for his achievements in the field of engineering and policy leadership in regional government, surface transportation infrastructure and research. In 1999, he was elected to the National Academy of Engineering.
The Ministry of Highways is divided into the Operations, Policy and Programs, and Corporate Services Divisions and the Communications Branch. The ministry is the employer of over 1,476 employees diversified amongst 105 communities in Saskatchewan. The current Minister of Highways and Infrastructure is Fred Bradshaw.
The AAA Foundation for Traffic Safety is a non-profit, charitable organization based in Washington, DC, that is dedicated to saving lives through traffic safety research and education. Since its founding in 1947, the AAA Foundation has sponsored over 200 projects related to highway safety, covering topics such as distracted, impaired, and drowsy driving; road rage; graduated driver licensing; driver's education and training; and pedestrian safety. The AAA Foundation research agenda is centered on four priority areas: Driver behavior and performance, emerging technologies, roadway systems and drivers and vulnerable road users.
Victor Mendez is the former Deputy Secretary of Transportation from 2014 to 2017 and was previously sworn in on July 24, 2009, as Administrator of the Federal Highway Administration (FHWA), the 18th person to hold this position.
For concrete cracking see Crazing
Diamond grinding is a pavement preservation technique that corrects a variety of surface imperfections on both concrete and asphalt concrete pavements. Most often utilized on concrete pavement, diamond grinding is typically performed in conjunction with other concrete pavement preservation (CPP) techniques such as road slab stabilization, full- and partial-depth repair, dowel bar retrofit, cross stitching longitudinal cracks or joints and joint and crack resealing. Diamond grinding restores rideability by removing surface irregularities caused during construction or through repeated traffic loading over time. The immediate effect of diamond grinding is a significant improvement in the smoothness of a pavement. Another important effect of diamond grinding is the considerable increase in surface macrotexture and consequent improvement in skid resistance, noise reduction and safety.
The National Cooperative Highway Research Program (NCHRP) conducts research in problem areas that affect highway planning, design, construction, operation, and maintenance in the United States. Spearheaded by the Transportation Research Board (TRB), part of the National Academies of Sciences Engineering and Medicine, it is jointly supported by federal agencies, state departments of transportation, and other nonprofit organizations.
The LTPP International Data Analysis Contest or the LTPP Data Analysis Contest is an annual international data analysis contest held by the American Society of Civil Engineers and Federal Highway Administration. As the name suggests, the participants are supposed to use the LTPP data in their analysis. The winners of this data analysis contest are announced in the early January during the Transportation Research Board annual meeting.
Pavement performance modeling or pavement deterioration modeling is the study of pavement deterioration throughout its life-cycle. The health of pavement is assessed using different performance indicators. Some of the most well-known performance indicators are Pavement Condition Index (PCI), International Roughness Index (IRI) and Present Serviceability Index (PSI), but sometimes a single distress such as rutting or the extent of crack is used. Among the most frequently used methods for pavement performance modeling are mechanistic models, mechanistic-empirical models, survival curves and Markov models. Recently, machine learning algorithms have been used for this purpose as well. Most studies on pavement performance modeling are based on IRI.
Levels of service (LOS) is a term in asset management referring to the quality of a given service. Defining and measuring levels of service is a key activity in developing infrastructure asset management plans. Levels of service may be tied to physical performance of assets or be defined via customer expectation and satisfaction. The latter is more service-centric rather than asset-centric. For instance, when measuring the LOS of a road, it could be measured by a physical performance indicator such as Pavement Condition Index (PCI) or by a measure related to customer satisfaction such as the number of complaints per month about that certain road section. Or in the case of traffic level of service, it could be measured by the geometry of road or by travel time of the vehicles, which reflects the quality of traffic flow. So, levels of service can have multiple facets: customer satisfaction, environmental requirements and legal requirements.