ARAN - Automated Road Analyzer

An ARAN is a specially modified vehicle that houses an extensive set of sensors (including laser reflectometers, ultrasonic sensors, accelerometers, global positioning systems, gyroscopes, video and machine vision systems) and computers, along with other highly advanced technology subsystems. The purpose of all this technology is to provide transportation departments with information about their roadways and right-of ways, including their condition and the location of specific features and/or faults. This data is critical to the management decision process that involves billions of dollars of assets, and maintenance budgets of millions of dollars each year.

An ARAN provides information to support better management decisions by collecting consistent, accurate, data quickly and cost effectively. It is capable of measuring up to 15 different data items in a single pass, with very high accuracy. This data can be collected continuously, at traffic speeds from 15 mph up to highway speeds. Some of the information that can be collected includes:

• The ride quality of the roadway [longitudinal profile / roughness (IRI)]
• The wearing of the roadway in the wheel paths [rutting]
• The grade and cross-slope of the roadway
• Real time video imagery of the roadway pavement and right-of-way imagery
• Precise location information of specific features on or near the roadway
  (Purchase of Surveyor software required)
• Faulting of concrete pavements

The City of Tucson's Pavement Management Staff is currently working on making much of this data available as colored roadway segments on a map of Tucson that will be accessible via the internet.

The Tucson Right-of-Way Video Log ARAN

The City of Tucson's ARAN incorporates direct to disk Videologging supported by two on-board computer workstations, and Inertial Profilometry measurements, all geo-referenced by GPS and an on-board Distance Measurement Instrument (DMI).

Roadware's Surveyor software allows measurements of specific features on or near the roadway to be taken directly from video images stored on a hard disk. The City of Tucson ARAN has two Surveyor video cameras. The resolution of these full-frame cameras is maximized by digitizing the camera signals in real-time to record the digital data from each camera system directly to separate computer hard drives. Images can be captured at predetermined intervals; randomly in real-time; or continuously and are delivered on CD or Jazz cartridges. A video banner describing the roadway can be optionally burned to the images.

Additional software is used to evaluate and monitor the roadway condition and plan maintenance activities.

POS/LV Enhancements

The City of Tucson's ARAN is fitted with a POS/LV fiber optic inertial navigational system and an Ashtech Global Positioning System capable of real-time differential corrections, which records its position to sub-meter accuracy.

In 1995, Roadware Corporation introduced a highly advanced position and orientation measuring system (POS/LV) as an upgrade to its standard GYRO package. With enhanced measurement of vehicle roll, pitch and heading, other on-board systems and office applications relying on this data reflect an increase in accuracy and repeatability. The POS/LV has been completely re-engineered to provide a broader range of capabilities with improved reliability and performance. Hardware improvements include:

• A new Inertial Measurement Unit (IMU) incorporating Fiber Optic Gyros (FOG) with solid-state accelerometers for superior reliability.
• An integrated GPS receiver facilitating real-time position fill-in.
• Support for a second receiver for real-time, differential corrections.
• An enhanced navigation 'engine' that blends inertial measurements with GPS and DMI measurements for position, attitude, dynamics and velocity updates at up to 50Hz
  (3x that of the original POS/LV).
• The improved initialization algorithm no longer requires vehicle to be at rest.

Software and control improvements include:

• Support for simultaneous distance-based and time-based data streams.
• Time-based data includes geographic position and velocity, vehicle attitude (roll, pitch and heading), vehicle dynamics (accelerations and rates-of-change of attitude) and vehicle (x, y, z) velocities.
• Superior fault detection and recovery from hardware failures (the software automatically recovers from a hardware reset without necessitating a complete system reboot).
• On-the-fly configuration changes are dynamically integrated into the POS/LV hardware (in virtually any mode of operation).
• Roll, pitch calibration algorithm to zero-out subtle offsets between the measured attitude and the 'known' attitude.
• POS/LV automatically 'remembers' the vehicle's previous geographic position and can use this data to speed-up system initialization in the event that a GPS fix is unavailable.

The new POS/LV has been incorporated into the ARAN delivered to the City of Tucson.

Applications

The following list of applications illustrates the versatility and capability of an ARAN and its associated software:

• Pavement Management Systems (PMS) (map)
• Highway Performance Monitoring Systems (HPMS)
• Geographic Information Systems (GIS)
• Bridge Management Systems (BMS)
• Right-of-Way and Pavement Video Logging
• Sign/Roadside Asset Inventory
• Construction & Design
• Planning & Maintenance
• Accident Investigation/Forensics
• Safety Enhancement

For further information please contact Casey Townsend at (520) 837-6663.