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Archived Data User Services (ADUS)

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Types of Data Collected by TMC's
Rationale for Archiving Data
Potential Benefits
History
Assessment
ADUS Standards
Case Studies
Information on Traffic Data Collection
References

TYPES OF DATA COLLECTED BY THE TMC

Traffic management centers collect traffic and incident information about the transportation network; this data is then combined with other operational and control data in order to manage the transportation network and to produce traveler information. Archiving this data is an effective way of making it available for operators who want to make improvements to their particular transportation system.

The data TMCs collect typically includes:

Vehicle traffic volumes
Traffic incidents (time sequence of events, location, cause, number of lanes blocked, etc)

It may also include:

Vehicle speeds
Travel time and delay distribution
Current and scheduled work zones (location, number of lanes closed, scheduled duration, etc)
Vehicle emissions
Vehicle classification (percent trucks)

RATIONALE FOR ARCHIVING DATA

Archiving these data provides a cost-effective way to obtain data that can be used by transportation planners, designers, and researchers alike for many purposes. Data can be used for facility planning and design, developing control strategies, congestion tracking, emissions modeling, deployment of response personnel, and schedule of maintenance and construction. Traffic management centers in particular can use archived data to analyze performance measures, determine the optimum ways of managing crises, and ultimately develop other means of operating the transportation system at its maximum efficiency.

POTENTIAL BENEFITS

Huge volumes of data are available at relatively low costs.
Allows for better long-term transportation management and planning.
The detailed nature of ITS-generated data allows for more accurate analysis and makes possible those applications that were previously too costly to undertake.
Removes temporal sampling bias from estimates.
Allows for the study of continuous variability in system performance and response.
Improves the evaluation of ITS deployment.
Promotes integration of ITS with traditional information systems.
Encourages the use of data for multiple purposes.
Mutual interest in data generated by ITS will stimulate cooperation among stakeholders, which could lead to the "main streaming" of ITS into standard transportation practice, particularly among transportation planners.

HISTORY

The need for archived data was initially expressed in the mid-90s at the Highway Performance Monitoring System Steering Committee on August 7, 1996 and later at a conference in Irvine, CA in March 1997. In January 1998, the FHWA sponsored a meeting to discuss the uses of archived data, the end result of which was a decision to revise the National Architecture to include a new user service, namely the Archived Data User Service (ADUS). In September 1999, ADUS was officially added to the Architecture. In May 2000, the FHWA developed an ITS Data Archiving Five-Year Program Description, which explains the need for a Federal program that addresses the archiving and multi-agency use of data generated from ITS applications.

ASSESSMENT

Development of Archived Data Services

Archived data services is relatively new and only a few state DOTs and associated transportation organizations have begun to implement this service as part of their daily operations. Those DOTs and TMCs that regard archived data as valuable for future planning and operations improvements have implemented their archiving systems to varying extents. The Metro District Transportation Management Center in Minneapolis, MN has been continually archiving traffic data since 1984 and has used it extensively for traveler information purposes, whereas the Dallas, TX DOT has archived only a few types of data somewhat intermittently. Another approach to archiving data was taken by the TransPort program in Oregon, where a specific type of data (i.e. loop data) was archived — in an experiment independent of the ODOT’s normal operations— in order to prove the utility of archiving data for future applications. TransPort installed 10 mainline inductive loop detector stations and associated on-ramp detectors at 10 eastbound on-ramps along an 11-mile corridor along eastbound US 26 in Portland. Vehicle counts, occupancy and speeds were archived, and it was determined that such simple, directly measurable variables would be useful in setting standards and determining widely-applicable performance measures. Still other DOTs nationwide are archiving several types of data simultaneously, but most have not gathered a substantial amount of data over a long enough period of time to use for noteworthy planning and operations improvements. However, the value inherent in having such archived data is widely recognized and its planning and operational benefits highly anticipated. Those DOTs and transportation agencies that are archiving data have determined that most data users prefer to access the data in an online format or on CD-ROMs.

The State of ADUS Today

Although archived data user services are potentially a rich resource for improving many transportation decisions, most notably for enhancing transportation planning and operations, not many regions are employing ADUS, mainly because this service requires a significant amount of institutional evolution, particularly in terms of infrastructure investments. Although ADUS is new to the ITS Architecture, it is expected that more and more TMCs will recognize the value of implementing a performance measurement system based on archived traffic data.

Implementation and Operational Barriers

The reluctance to share data among jurisdictions will continue to hinder full ADUS implementation.The lack of ADUS standardization for both data
Data quality and accessibility slows the integration of different information from multiple sources.
More efficient data checking methods are needed to ensure accuracy, and reliability, absence of bias, and validity of estimation methods.
Organizations like the TMC generally do not have the staff needed for both incident management and data archiving.
Data ownership, maintenance, or control issues may become problematic.
The planning community is not progressing as rapidly as the transit community on ADUS. This is because the entities that produce the desirable planning data (e.g. the TMCs) are organizationally separate from the data users (e.g. the planners).
TMCs are not collecting data explicitly on ITS Safety issues; those who are interested in safety have to find their own ways to relate ITS-generated data to the topic of highway safety.
Many agencies that collect data on incidents withhold safety data in order to honor privacy and liability issues.
It is unclear which entity should bear the cost of the various ADUS applications; whether it should be borne by the data user or provider (TMC) is still a major barrier to implementation. Currently, there are some data users who obtain data by paying the data producers directly; alternatively, there are some data brokers who make the data available to interested users at a cost.

Costs

Costs for implementing ADUS are needed to:
Articulate and communicate the needs for archived data
Save the data
Re-format the archived data into a user-friendly format
Re-vamp the existing software to accommodate archived data
Address data quality issues
Make archived data accessible in a timely manner
Integrate the archived data with non-ITS data to meet broader data needs
Reconcile data incompatibilities among different data sources
Forge mutually beneficial partnerships among data-producing agencies and data users

ADUS STANDARDS

The purposes of having standards for ADUS are to:

Define and promote the interfaces necessary to implement ADUS in the field.
Ensure consistent deployment of ADUS nationwide.
Eliminate duplicate data collection and storage.
Coordinate with other ITS data dictionary efforts that are relevant to ADUS.
Reconcile differences between the data definitions in pre-existing ITS data dictionaries and those of ADUS stakeholders.

Standards for ADUS are still under development, but it is important to note that any standards developed should take into account that the standards for each ITS entity will effect ADUS. Close coordination between ADUS and each ITS user service is thus essential. Aimed at creating “open” protocol standards that will serve the transportation information network and be adaptable to different communications architectures, the National Transportation Communications for ITS Protocol (NTCIP) is currently developing standards that will facilitate the use of ITS devices for data collection.

Below is a diagram of the various ITS Sources that interact with an archived data management system:

“Standards Will Promote the Development of Interfaces for Archived Data Management Systems” From the Strategic Plan for the Development of ADUS Standards, May 2000.

The diagram below illustrates the flow of data from its collection stage to its archiving stage:

"ADUS Standards Take Many Forms and Support the Various Process of the Data Stream" From the Strategic Plan for the Development of ADUS Standards, May 2000.

CASE STUDIES

Collected from studies by the Texas Transportation Institute, Cambridge Systematics, and PATH.

Dallas, Texas

Hampton Roads, Virginia

Montgomery County, Maryland

Portland, Oregon

Dallas, Texas
Daltrans is a component of the Dallas office of the Texas DOT that collects traffic information from intelligent transportation system. The Dallas district office currently operates closed circuit TVs (incident detection and management), changeable message signs (traffic control), online and media outlets (en-route and pre-trip traveler information), and lane control signs (traffic management). Daltrans currently collect video from CCTVs, incident information, current and scheduled work zones, and point data (volume, occupancy, and speed) from video.