Chapter 3. Case Studies (continued)
District of Columbia Department of Transportation (DDOT)
The DDOT is planning a performance-based comprehensive Asset Management system for the entire city. The department has recently issued two requests for proposals for the development of such systems for tunnels and roadways and is awaiting responses. The Asset Management division of DDOT is responsible for managing the District's transportation infrastructure: pavement, bridges, sidewalk, alleys, culverts, etc. The transportation network under DDOT's management includes: 1,100 miles of streets, 229 bridges, 1,405 miles of sidewalk, 335 miles of alleys, and 17 tunnels.
At present, the agency has several stovepipe systems that are not fully integrated. A pavement management system has been used since the 1980s. A consultant developed the original system, but the agency is currently migrating to PAVER. DDOT uses the AASHTO software PONTIS for bridges, and FHWA's tunnel management system for tunnels. The agency is also developing an engineering management system for alleys and sidewalks.
There are five distinct business units (administrations) inside DDOT: (1) transportation policy and planning administration, (2) infrastructure project management administration (IPMA), (3) public space management administration, (4) traffic services administration, and (5) urban forestry. The district is divided into eight wards, and each administration has its own team for managing the corresponding works under the wards. For example, IPMA has four teams that take care of the eight wards (two wards per team).
Projects are selected based on a combination of technical need and close citizen participation (through advisory neighborhood commissions). The technical offices prepare a list of candidate projects that is shared with the planners in the wards. They review the list, share it with citizens, and provide feedback. A revised list is prepared and submitted to the director and various associate directors, who review the proposals during monthly meetings and select projects based on the technical needs and the priorities established by the District's council and mayor. There are neighborhood infrastructure oversight officers who are responsible for seeking out deficiencies in their respective areas of the city and reporting them to the appropriate administrations. Citizen-reported deficiencies are also distributed to the appropriate person or office through a centralized call center.
In the last couple of years, DDOT started a 5-year pavement restoration program. DDOT implemented the program with two indefinite-delivery-indefinite-quantity contracts: one for local streets and one for federally-owned streets. The contractors work on pavement rehabilitation projects. The Asset Management division has developed performance measures for each asset and is working on a pilot experimental total Asset Management Partnership to include all assets (e.g., signs, lights, sidewalks, etc.) in collaboration with inhouse service providers.
For the 75 miles of the National Highway System (NHS) in the District, DDOT had a 5½-year performance-based contract. The contractor was responsible for maintaining all assets within the right-of-way (ROW) except traffic signals.
The DDOT is conducting a major project to inventory all assets in its transportation system and is developing the ADA Transition Plan. The assets are categorized into 34 groups. A consultant collects the inventory data in the pilot program, and some data also are reduced from the ROW camera information collected for the pavement management system.
In addition, the DDOT collects data for several of their main assets as part of their individual management systems:
- Pavements: DDOT conducts annual condition assessment through contractors to identify different distresses on pavement for each block segment and computes a pavement condition index (PCI on a scale of 0-100) on the basis of the individual distress types. Other performance measures such as the international roughness index (IRI) also are collected. The agency is expanding its pavement data collection by changing from one lane in each direction to every traveled lane in both directions. DDOT used to collect citywide pavement data every year, but the frequency has been reduced to every other year for local pavements and every year for Federal pavements.
- Bridges: Consultants conduct annual bridge condition assessments (following the PONTIS guidelines). If the contractor identifies some critical problem that needs to be fixed immediately, the maintenance contractor will receive a task to fix the problem from DDOT. Approximately one-third of the bridges are assessed every year.
- Sidewalks and alleys: There is an ongoing effort to develop a 6-year sidewalk-and-alley rehabilitation program. Data collected include GPS, pictures, length (extension), condition, and maintenance needs, among other attributes, and sidewalks and alleys are still in the process of inventory. The project selection will be based on both DDOT assessments and requests from citizens.
Public opinion also was considered in the performance rating process. DDOT organized a tour of the transportation system every 2 weeks as part of the assessment for the NHS asset preservation contract to evaluate cleanliness. The evaluators were provided with rating manuals before the tour, and they rated the various management units-3-block segments in the inner city and 2-mile segments on the highway. The results were forwarded to the contractor to help him prepare his work plans. The public also can review the work plans and give comments and suggestions. The process enables DDOT to maintain good communication with its neighborhoods and effectively provide the needed services.
Both the Central Office and individual branch agencies (parking, street lights, signs, and bus and mass transit) collect data on the assets that are their responsibility. The Asset Management division collects more detailed performance data, whereas individual branch agencies collect data that are more related to the selection of appropriate maintenance treatments. DDOT plans to make the asset condition information easily available to the public.
Whereas some of the information is stored in a central database, most of the individual branches maintain their own databases. There is a central repository (Web portal) that was developed for the NHS that includes all documentation related to the project. DDOT is investigating the possibility of expanding it for the entire city.
Data collection methods differ from asset to asset. For sidewalks and alleys, the contractor conducts a walking, visual inspection using laptops and PDAs. Pavement data are collected using automatic data collection vans equipped with cameras. Access equipment and laptops are used to support the bridge data collection.
The data collection costs vary by asset types. For pavement, DDOT paid its contractor $193 per mile for the data collection, which includes individual distresses, ride quality (IRI), and PCI. The contract for sidewalk and alleys has a lump sum cost. The contract included the development of a rating system, a citywide inventorying, and collection of condition information.
The DDOT is trying to evaluate tradeoffs among different types of assets by participating in a pilot program that evaluates the analytical tool recently developed by NCHRP. Currently, most of the project selection is done within the individual stovepipe management systems.
The budget for bridge projects is relatively constant every year. The FHWA provides about $28 million for bridge projects. There is more flexibility with roadway project budgeting even though the district receives some Federal funds every year. The Asset Management division develops a proposal about the works to be done and submits it to the teams. The director and associate directors, in cooperation with the teams, make the final project selection decisions.
The PMS identifies appropriate treatment for each block based on distress types and severity. The system also includes a cost module that is used to calculate costs for the candidate projects. The divisions then use cost-benefit analysis and project-to-project comparisons to determine the final list of prioritized candidate projects submitted for consideration by the director.
Because the assets managed by DDOT are located within the urban area, they cannot be evaluated using the same criteria and performance measures used by other States. For example, the IRI of pavement segments near traffic lights and stop signs could easily go beyond the national threshold value. Congestion (stop/go), multiple manholes, utility cuts, reducing and picking up speed before and after traffic lights, and other urban conditions affect IRI. For bridges, functional deficiencies identified by PONTIS (i.e., geometric design problems) are often overridden because fixing these problems usually is not feasible in a congested urban area.