A pilot project on the measurement of the night visibility (retroreflectivity) of road markings on the main roads of Estonia using a mobile retroreflectometer.

The contracting authority:

Estonian Road Administration. Tallinn

Report date:

July 2017

Participated in the work of the contract:

Mr. Tiit Kaal, Consultant: ERC Consulting Ltd. Estonia, Mr. Joe Turley CEO, Reflective Measurement Systems Ltd. Ireland

 TABLE of CONTENTS:

  1. Introduction
  2. Retroreflectivity
  3. RetroTek-M measuring system
  4. Summary of the measurements
  5. Recommendations and Proposals to ERA.
  6. Profiles of Parties involved.

1. Introduction

In early 2017, The Estonian Road Administration (ERA) issued a tender to complete a pilot survey of road marking retroreflectivity condition of all main roads in Estonia. This was the first such survey of the main road network in Estonia.

The ERA wanted to know the current condition and night visibility of horizontal line road markings on all lanes and wanted recommendations on what road asset data could & should be collected in future surveys.

ERC Consulting Ltd in collaboration with Reflective Measurement Ltd (Ireland) using the RetroTek-M technology were successful in securing the tender to commence in May 2017. This is a summarised account of the report compiled by ERC Consulting Ltd for the ERA.

The contract was completed for the ERA (Estonian Road Administration) in cooperation with the ERC Consulting Ltd. Estonia and Reflective Measurement Systems Ltd. Ireland within the framework of the pilot project on the main roads of the country using the vehicle mounted mobile RetroTek-M retroreflectometer to measure the retroreflectivity (RL) road marking measurements.

The following measurements were recorded.

  • Time and date of measurement.
  • GPS coordinates of measurements
  • Retroreflectivity RL [mcd/m2/lx]
  • The air temperature.
  • The air humidity.
  • Road video of all measurements

The road markings on all state main roads were measured for retroreflectivity (RL).

The measurement results are presented separately for each of the lines on each road with Excel files to enable the ERA review markings measured on the lanes. In addition, the measurements are recorded with GPS correlated video (in the direction of each of the separate lanes). The ERA has access to the MultiView Mapping & video analysis system where it is possible to view all the GISbased road surface recoded retroreflective results.

Figure 1. The MultiView Mapping & Video presentation of the measurements collected

 2. Retroreflectivity.

Retroreflectivity describes the ability of a surface to return light to its source. Retroreflectivity is one technology used to enhance the readability and perception of information displayed in low-light and night-time conditions. http://www.reflective-systems.com/retroreflectivity/

The road maintenance industry recognizes that legible traffic signs and quality pavement markings are important for highway safety, especially in low-light conditions and at night.

The retroreflectivity of traffic signs, pavement markings and raised pavement markers provides positive visual guidance to assist driver’s awareness of lanes and road edges. They provide critical warning, timely location and other information to drivers. The retroreflectivity of signs and road markings is critical to a safer road environment.

Figure 2. Retroreflectivity and Glass Beads used in road markings for night visibility.

As effectiveness of retroreflective materials tends to deteriorate over time, regular maintenance is important. Signs and road markings lose their colour, legibility, and retroreflectivity as a result of corrosion caused by exhaust fumes and industrial pollution, erosion caused by vehicle tyres, sun exposure, dirt, ice and wind. Regular inspection and measurement ensures that minimum acceptable standards are maintained.

Due The requirements for the measurement of the retroreflectivity le and the Road Markings are defined in the standard EVS-EN 1436:2007 + A1:2009.

 3. RetroTeK-M Retroreflectometer Measuring System.

The RetroTek technology was used to survey the Road Markings retroreflectivity. Developed by Reflective Measurement Systems Ltd. Ireland, this retroreflective system is the next generation of mobile devices for the measurement of the performance of reflective road assets including lines, markings, markers & barrier reflectors.

Figure 4. RetroTek-M system installed on vehicle in Estonia.

This technology measures the performance of up to six different road assets simultaneously across the full width of a traffic lane in one pass at all traffic speeds. The data collected include the retroreflectivity (RL) of road markings (the lines, symbols, arrows, etc.) and the existence of road markers (RPMs) and barrier reflectors.

Figure. 5. RetroTek-M collects performance data on up to 6 road assets -Road Lines, Symbols, Studs & Barrier Reflectors.

The data collected is processed in real-time with individual reports generated for each individual asset. The advantages of the RetroTek-M system are that it is easy to calibrate and operate by one person/driver and only normal driving behavior is required (precision driving close to a line, is not necessary). Provides accurate and repeatable results at all traffic speeds to comply with local speed limits without traffic disruption. It is fitted to the front of the vehicle with sufficient road clearance therefore not a safety issue for the operator/driver & other road users. Measurements for RL must be performed at night. Detailed Road Markings retroreflectivity measurements are given in electronic form over a simple Excel files, where each of the roads measured by lane are listed.

Figure 6. The various retroreflectometer devices currently available for Road Markings

RetroTek-M, the measuring system contains a sensor, which is installed in the front of the vehicle, and powered by the vehicles battery. It is operated from a laptop within the vehicle connected with an ethernet cable. The sensor measuring device includes a CPU, digital cameras, Led light source, projection optics, GPS’s, and related control circuits, including Wi-Fi and 4 g wireless mobile communication option, which allows access to update software etc.
The measuring apparatus weighs around 40kg and its source is the LED light bulb, in which life is around 15 000 operating hours. The measuring temperature is in the range of 0 ° C to + 55 ° C.

The technology has been developed to comply with CEN Standard EN 1436, standard for Road Markings and EN 1463 standard for road markers (studs)], and the ASTM Standard test method E1710.

The RetroTek-M device measurement accuracy is not affected by speed and measures the retroreflectivity values to within +/-5%, which corresponds to the industry standards set by handheld retroreflectometers.

In June 2015 StrausZert independently evaluated the RetroTek-M technology – Certificate No. 09132015-02 EN 1436. The certificate certifies the RetroTek-M mobile retroreflectometer is suitability for measuring the retroreflectivity of different types of Types of road markings including, thermoplastic, agglomerations and tapes.

The RetroTek-M, as well as the retroreflectivity (RL) of Road Markings, also measures the width of the lines and lane widths. The system also saves the time the measurement was collected, date, start and end times, the distance measured, speed, road name, lane, temperature and the humidity. The MultiView software also provides the results with GPS linked mapping & video for analysis & reviewing.

4. Summary of Measurements

The total length of main roads of the country surveyed for night visibility was 3,721.6 kilometers. Road Markings retroreflectivity condition of the road markings was graded to the threshold values below.

  • Very good – RL > 100 [mcd/m2/lx]
  • Good – RL = 80-100 [mcd/m2/lx]
  • Satisfactory – RL = 60-80 [mcd/m2/lx]
  • Bad – RL < 60 [mcd/m2/lx]

In summary, the length of main roads that needs immediate improvement was only 7.7% of the total main road network (RL value below 61 [mcd/m2/lx]), approximately 300 km. However, the relatively low value of RL value between 60-80 [mcd/m2/lx]) was 15% of the main roads (546.5 km).

 5. Recommendations & Proposals to ERA.

As a result of this pilot survey of the main roads of Estonian, measuring the retroreflectivity (RL) of road markings carried out in the year 2017, the following recommendations are suggested:

  • Road Markings retroreflectivity (RL) measurement surveys of the Estonian network should continue. The existence of the Road Markings and their compliance with international requirements is an important safety parameter that will help road users and improve road safety and have a positive socio-economic impact.
  • Measurements should start in the spring to get dry weather and as early as possible after the winter dust and grit is removed from roads. Roads must be completely dry during the surveys. During this project, the survey was to be completed from May and completed by the end of the month. This was difficult due to weather conditions as rain & humidity has adverse effect on results. It is also very difficult to plan as weather was so undependable. Suitable realistic time frame should be given for future surveys.
  • The measurement of retroreflectivity at night or during the day has little effect on the results but each has its advantages and disadvantages. At night, the surveys are generally safer and calmer, when low traffic volumes. There is much movement of wildlife and accidents can occur causing injury and damage to the system & vehicle. During the day, there is traffic congestion and a lot of other road users & slow traffic with vehicles cutting in front of the survey vehicle at slow speeds which could cause measurements to vary.
  • Road Markings performance contracts should be issued for longer terms (at least 3 -5 years). This will give the road authorities issuing the contracts the assurance of quality road markings for the duration of the contract getting the best return on their investment. This will ensure that the standards and the consistency of the performance of the road assets will be maintained by annual road asset performance measurement surveys.
  • The planning of the surveys within the framework of this project was a problem due to the of the lack of information on the number of lanes on each road network. Futuresurvey project proposals should include the number of lanes, exits & entrances, number & type and all GPS coordinates.
  • Future surveys should also include the retroreflectivity of road markings /symbols in the center of the traffic lane as this data can be collected at the same time as the road lines left & right of the lane.

6. Profiles of Parties Involved.

Estonian Road Administration.

The Estonian Road Administration (ERA) is a government agency operating within the administrative area of the Ministry of Economic Affairs and Communications. On the basis and to the extent prescribed by law, the ERA performs the implementation of state policy and development programmes, management functions, state supervision, and applies the enforcement powers of the state in the field of road management, traffic safety, public transport and the environmental safety of vehicles. One of ERA’s main functions is road management and creation of conditions for safe traffic on national roads.

Mr. Janno Sammul, Development Manager. Traffic Management Department, Estonian Road Administration (ERA) commented after the Survey contract was completed –

“ERA was very happy with the survey results and impressed with the RetroTek MultiView Cloud software with interactive data base, mapping and video analysis. It gives good overview of results and opportunity very easy to plan further road marking replacement plans.
The timescale was tight and due to weather conditions, it was very hard to keep in timescale. But despite that the delivery was enabled by the efficiency of the contractor ERC Consulting Ltd and RetroTek-M system”.

ERC Consulting Ltd

(ERC) is Estonian capital based consulting company established in 1993. Providing to our customers high level road and traffic-related consulting and R&D services. Our consultants have extensive work experience in their field of expertise, both in Estonia and elsewhere in the world. ERC Consulting Ltd has business relationships and contacts with various Estonian and international companies, consultants and experts. Included in their expertise is Pavement and traffic R&D, Pavement condition measurements & Pavement condition analysis.

“The flexibility of RetroTek has allowed ERC to meet and exceed the stringent requirements set by ERA. Its easy setup, ability to measure line retroreflectivity on both sides of a lane and then illustrate these results on the MultiView mapping & video interactive platform, made the RetroTek-M a competitive choice”
Mr. Tiit Kaal. Consultant: ERC Consulting Ltd. Estonia

Reflective Measurement Systems Ltd.

RMS Ltd based in Ireland developed the RetroTek technology in 2016. Is an Enterprise Ireland HPSU and Horizon 2020 supported and setup to provide competitive high-speed machine vision solutions for the global road maintenance industry?

Whitepaper published on 25 August 2017

 roadtraffic-technology.com website and the full pdf of the report can be downloaded from there.

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