ROMDAS

OVERVIEW OF ROMDAS

The ROMDAS system is illustrated below:

It is possible to use ROMDAS for:

• roughness surveys
• travel time and congestion surveys
• condition rating surveys
• inventory surveys
• transverse profile/rutting surveys
• as a digital trip meter
  

ROMDAS allows the use of a laptop or notebook IBM compatible PC to record the following data during a survey:

• roughness meter counts
• vehicle speeds and, optionally, acceleration
• odometer readings
• pavement condition or roadside events by observation through the PC keyboard.

The first three data items above are recorded through electronic pulses which are sent to the ROMDAS.

The basic ROMDAS hardwareconsists of:

• a hardware interface
• a digital distance/speed sensor which is spliced into the vehicle speedometer cable or attached to an electronic speedometer harness
• all necessary electrical plugs/sockets and cabling (harness)
• a test box for the interface

The hardware interface connects to a sensor on the roughness meter and to the distance/speed sensor. During the survey, the interface monitors both the distance/speed and the roughness meter. Every 0.1 s, the PC interrogates the interface and records the data. At the end of the survey the data are stored in dBASE-III compatible files.

The only permanent fixture in the vehicle is the distance/speed sensor. It is therefore practical to move ROMDAS between vehicles as long as they are fitted with a distance/speed sensor and harness. Since ROMDAS uses a portable computer as the data logger, the computer may also be used for other activities in between surveys.

A response-type roughness meter can be added to measure road roughness. ROMDAS will convert raw roughness data into calibrated roughnesses through user-supplied equations. If equations are available for different speeds, ROMDAS will apply the appropriate equation given the vehicle speed at the time of the measurement. This removes the constraint of trying to operate the vehicle at a single survey speed under all conditions. If the only requirement is a simple roughness survey, ROMDAS can be run by the driver alone, eliminating the need for an additional operator.

Travel time and congestion surveys can be conducted using ROMDAS. These will give the travel time, distances travelled and acceleration on a second-by-second basis. The system has been specifically designed to collect data for use in the World Bank's HDM-4 congestion model.

A 'Transverse Profile Logger' is available which can be used to measure the pavement transverse profile elevations using ultrasonics and to establish the rut depth. This instrument stores raw elevation data which are downloaded to the PC after the survey to calculate the rut depth under a user-definable straight edge. The transverse profile distortion is used to estimate potential causes of rutting.

A video recorder can be used to record data on the pavement right-of-way or the surface. This is connected to the computer video port through a character overlay device which superimposes the survey chainage and other basic data on the tape.

LPCD Longitudinal Profile Calibration Device is an instrument used to accurately measure the road profile