Traffic Speed Retroreflectivity (TSRR)
For many years retroreflectivity of traffic signs and road markings have been measured solely by retroreflectivity meters, either by manual means or in the case of road markings by mounting a meter on the side of a vehicle. Impulse Geophysics have called on their 20 years plus experience using pavement video technology to develop a high speed retroreflectivity system that can collect data at traffic speed, at night, safely and analyse the data on the actual performance of traffic signs and road markings. The system is designed to collect information on luminance and convert this to retroreflectivity using information from a large volume of laboratory and field trial data.
The system comprises of controlled lighting alongside high resolution (4K) cameras specifically calibrated for this application. Multiple cameras are used to pick up information on all sign faces and road markings on multiple lanes in one survey pass. The night vision system is integrated with the day vision system to produce a full picture of sign and road condition. The standard sign inspections can be carried out from the day vision system – ROADSHOW
By using a video system calibrated to the human eye instead of using retroreflectivity meters, the actual performance can be measured in terms of the true sign/road markings interaction with the driver where other factors, such as sign orientation and obstructions, can be taken into consideration.
As always with video systems, they allow a greater degree of quality assurance rather than relying on discrete measures, and in this case, taken from retroreflectivity meters. The sign/ road marking images are stored and archived. With more and more traffic on the UK's roads and Hardshoulder running it is no longer possible to carry out the traditional methods due to safety concerns.
Not only is Traffic Speed Retroreflectivity (TSRR) cost effective it is inherently safe and produces consistent results to allow comparisons year on year. The system is designed to target maintenance using the intervention levels from the DMRB. Additional modules are available to look at road studs from the same night vision survey.
The resultant luminance / retroreflectivity data is stored in a geo-referenced database and outputs can be tailored to individual clients needs.