Some excerpts from the Paper
“The functionality of traffic signs depends on their visibility and recognisibility during daytime and night-time. During the day this requires that the sign face and symbol colors are not faded in such a way that it becomes impossible to recognise the message that the sign is trying to deliver. Additionally, during night-time, the sign should be able to reflect the light from the headlights of an approaching vehicle back to the driver of that vehicle. This requires that traffic signs are maintained on a regular basis and replaced either once their visual performance begins to fall below the desired level or in case of damage to the signs (e.g. vandalism).”
“The need, on behalf of road authorities, to urgently prioritise road sign maintenance by first, establishing an inventory of signs under their jurisdiction, second, assess their retro-reflectivity and establish a work plan for the replacement of non-performing signs ”
“For example, in Croatia, an extensive survey for traffic signs took place in 2014 to assess the condition of traffic signs on the network by assessing first their retro-reflectivity, second their technical condition and third, whether they conform with national regulations in place. A total of 11717 signs were assessed over 625km performing manual measurements.
According to the survey’s conclusions, 20% or 2370 signs failed to meet basic retro-reflectivity requirements, which is practice means that they provide little or no value to users in terms of road functionality. The average life of signs was 11 years. An additional 12% or 1385 signs failed due to other parameters, bringing thus the total percentage of non-compliant signs to 32%!
“Modern technologies exist today, with further scope for development, allowing road authorities to measure the condition of their traffic signs in quick, safe and cost-effective manner. In recent years, dynamic vehicle –mounted methodologies for monitoring traffic signs have been developed replacing traditional manual inspection techniques, thus allowing authorities to obtain a clear picture of the condition of their network.”