Past Issues of Government Technology

Full Digital Blacktop

Arkansas solves the problem of integrating video into a digital information system.

by , , / May 31, 1997 0
Two types of engineering information are widely used in highway departments: (1) video images collected through photo or video logging and (2) tabulated site data. The video images provide visual information for pavement management, highway signing and marking improvement, and accident analysis. The tabulated site data contains information on construction and rehabilitation history, pavement layer information, pavement width and type, average daily traffic, accident history and signing, and marking inventory.

Currently, analog-based video information is limited
in accessibility and usability. Simultaneous and synchronized access to both visual information and tabulated data is presently not possible. The capability of multiple-use access cannot be provided by existing systems. The analog nature of the video signals also presents difficulties in integrating the visual information with other types of data.

In 1995, recognizing the shortcomings of current photo logging systems and the potential of new technologies, the Arkansas State Highway and Transportation Department initiated a research project to develop a full-digital, networkable and MultiMedia-based Highway Information System (MMHIS). The Civil Engineering Department of the University of Arkansas, Fayetteville, received the contract to conduct this research at the Intergraph Transportation Lab, donated by Intergraph Corp. Reasearch support also came from the Mack-Blackwell Transportation Center, founded by a grant from the U.S. Department of Transportation and located at the university.

MMHIS utilizes advanced technologies in digital video, computer networking and video server to combine video and tabulated site data into a comprehensive information source. MMHIS also provides full-motion digital video at 30 frames per second and synchronized site data, instead of the still images provided by previous systems.

The highway video is presented along with the corresponding site data. Data sets shown in the table above the video present location and accurate information on the road. There are also two windows showing two graphs containing roughness and rutting data. Dynamic graphing is built into the two graphing windows, allowing the user to view the values of various attributes, such as roughness and rutting with curves, showing values for the entire road section. A vertical bar on the curves indicates the location of the road.

The following operations can be conducted with MMHIS:

Running the video. While the video is playing, information in the site data window will change accordingly. The video's play speed, the video window's size and many other factors can also be configured through the menu button next to the play/stop button.
Dragging the video to a new location of the highway. Use the mouse to drag the slider on the slider bar at the bottom of the video window.
Changing the data update rate for site data table. The fastest data update rate is every 25 meters. The actual displaying rate and quality of video motion is limited by the machine speed and the distance spacing among adjacent records in the database. Currently the database contains records for every 25 meters.
Opening another query. The user can open multiple video windows simultaneously, and windows of each query can be resized and repositioned. The system allows the running of one query's video while all the other queries' videos are frozen.
Multiple query in MMHIS. The system allows users to choose which way to proceed at intersections or exit ramps. When the vehicle approaches an intersection or an exit ramp, the highway video pauses and MMHIS displays arrows to show possible turning movements. Users can click on one of the arrows to make turns. If none of the arrows is clicked for a certain time (10 seconds), the system will take the default option of the "through movement" and the video continues.
User selectable turning movements in MMHIS hardware and software environment. MMHIS runs on IBM compatibles with an operating system of Microsoft Windows NT version 3.51 or later.
The current system also uses motion JPEG format to store and replay the highway-section videos. An MMHIS-capable computer requires a motion JPEG encoding/decoding board to work with the video files. Engineering site data are stored in Microsoft Access Version 7 format. Microsoft's Visual C++ version 4.2 is used to develop the main operating environment of the MMHIS. Open Database Connectivity drivers are used as the database interface for this system.

MMHIS provides unprecedented multimedia data viewing capabilities to highway engineers. It allows a highway agency to efficiently examine road and roadside structures without taking certain field trips. In addition, MMHIS is effective in communicating design and improvement ideas among engineers and managers and to the general public.

Additional work underway includes:

Applying more advanced video techniques to reduce the storage requirement and improving video quality, such as MPEG-2.
Further enhancing the dynamic graphing capability by providing space-time 3-D zooming functions.
Studying approaches to using 3-D terrain visualization techniques to display statewide terrain surface, so that MMHIS queries will be readily conducted on a 3-D surface map in a GIS environment.
Kelvin C.P. Wang, Robert P. Elliot and Xuyang Li are in the Department of Civil Engineering at the University of Arkansas.

PROBLEM/SITUATION: Integrating video into a
highway information system.

SOLUTION: Multimedia system which uses digital video.

JURISDICTIONS: Arkansas State Highway and Transportation Department; University of Arkansas.

VENDORS: Intergraph, Microsoft.

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