(B)RUSHING OVER THE CRACKS

The development of a method for rapid assessment of pavement condition without having to cone off lanes and conduct time-consuming visual inspections is described. The Highways Agency Road Research Information System (HARRIS) was produced by TRL for the Highways Agency, UK. Research at TRL indicates that much deterioration of thick flexible pavements starts as cracking at the surface and that this cracking is the major determinant of the life span of the pavement. Automatic detection of this cracking would enable rapid remedial work to be carried out. Techniques for collecting and recording detailed video images of a traffic lane were developed using specialised digital cameras. Then a variable width transverse profile bar was fitted onto the front of a specially adapted vehicle, with additional high speed texture lasers. Both surface cracking and road profile information could be collected successfully in a single survey. Lighting for image collection is provided by a bank of 26 lights that enhance the visibility of any defects present on the pavement surface, and which enable the vehicle to be used day or night. Each line-scan camera images a strip of the pavement surface that extends 1 metre in the transverse direction and 2mm in the longitudinal direction. These strips are accumulated to give a 1 metre X 1 metre image frame with a 2mm pixel resolution. For automatic crack identification the image frames are transferred to onboard digital processors and subsequent storage on hard disk. 25 laser height sensors are used to measure the road profile at about 1.5mm intervals (when surveying at 80km/h) and cover the width of a motorway traffic lane. A three-dimensional image of the pavement surface is produced from data taken at 150 or 75mm intervals. A texture depth measurement system is also described. Accurate gyros measuring roll, yaw and pitch enable the absolute profile to be determined. All the measurements taken can be accurately cross-referenced to their location using differential GPS, inertial referencing, road stud recognition and infrared reflective markers. The development of a surveying vehicle for the new TRAffic-speed Condition Surveys (TRACS) contract is described. Other uses of the equipment such as noise prediction, targeted high-resolution profile surveys, and ride quality determination are undergoing research.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/32663949
• Corporate Authors:

  UK and International Press

  Abinger House, Church Street
  Dorking, Surrey  United Kingdom  RH4 1DF
• Authors:
  • FERNE, B
  • Wright, A
• Publication Date: 2002

Language

• English

Media Info

• Pagination: p. 96-8,100
• Serial:
  • Traffic Technology International
  • Volume: -
  • Publisher: AutoIntermediates Limited
  • ISSN: 1356-9252
  • Serial URL: http://www.ukipme.com/mag_traffic.htm

Subject/Index Terms

• TRT Terms: Automatic control; Automation; Cracking; Evaluation and assessment; Flexible pavements; Freeways; Image analysis; Image processing; Lasers; Maintenance; Measurement; Numbers; Pavements; Sensors; Speed; Traffic lanes; Video cameras
• Uncontrolled Terms: Profile (Longitudinal)
• Geographic Terms: United Kingdom
• ITRD Terms: 3882: Automatic; 6750: Camera; 5211: Cracking; 9020: Evaluation (assessment); 2944: Flexible pavement; 8633: Image processing; 6772: Laser; 2825: Longitudinal profile; 3847: Maintenance; 6136: Measurement; 2752: Motorway; 6432: Number; 2955: Pavement; 6120: Sensor; 5408: Speed; 2827: Traffic lane; 8119: United Kingdom
• Subject Areas: Highways; Maintenance and Preservation; Pavements;

Filing Info

• Accession Number: 00937740
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Feb 5 2003 12:00AM