Prüf-, Überwachungs- und Zertifizierungsgemeinschaft

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1 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation Berlin, 17 th July 2015 Test Certificate No regarding the suitability of the RetroTek-M Mobile avement Retroreflectometer for measuring the coefficient of retroreflected luminance R L of the surfaces of road markings (This test certificate comprises 13 pages and an appendix of 2 additional page) 1 Originator The order to draft the report was given by Reflective Measurement Systems Ltd. Rear 45 Terenure Road East, Terenure, Dublin 6, Ireland. 2 Brief Determination of the suitability of the RetroTek-M Mobile avement Retroreflectometer with 30 m geometry (referred to below as RetroTek-M ) for measuring the coefficient of retroreflected luminance R L of the surfaces of road markings by way of two different comparative measurement series. 2.1 Comparison with measurements from a portable measuring device Determination of the accuracy of the RetroTek-M by comparing the R L measurements from the RetroTek-M with those obtained with the portable (handheld) retroreflectometer LTL-XL on a road marking test field. The retroreflectometer LTL-XL, manufactured by DELTA Light & Optics, was approved by Strausert e.v. with test certificate of 14 th September 2010 as a measuring device to measure the night-time visibility R L and day-time visibility Q d of road markings. 2.2 Comparison of measurements at different speeds Determination of the dependence of the R L measurements from the RetroTek-M on the speed of the device on a road carrying traffic. 3 Tested measuring device The technical data of the RetroTek-M is determined using the originator's information and a visual inspection. Fleyer Strasse 204, Hagen, Germany strauszert@ivst.de Tel: , Fax:

2 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation The system operates using a pair of digital CMOS cameras and a projected LED light source. It acquires images at a rate of 20 image sets per second. The image sets are used to calculate the range to the objects being measured so the distance can be used in calculating the R L measurement. The system uses a LED with a colour temperature of about 3000 K projected across a 6 m wide area at a range of 15 m for measurement. The system thresholds the primary image and locates the road lines in this. It measures the intensity of the road lines, or sections of them. It measures the range of the line segments using stereo from a 60 cm span stereo camera pair. The system is calibrated for the lighting intensity variation across the field of view. Using the sample intensity, the range and the X position in view and a general calibration factor, it is calculated the R L of a sample. This can be done for any position in the calibrated area of approximately 5 m x 3 m at a distance of 15 m from the master camera. Special features of the system: The system can simultaneously measure road markings on the left and right sides of a lane. The system can measure continuous as well as dashed road markings at the same run. The maximum width for measuring both sides of a lane is about 4 m. The measurements must be performed in darkness. The technical data of the RetroTek-M is provided in table 1. 2

3 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation Measuring geometry 30 m, according to CEN-geometry (EN 1436) Observation angle EN 1436: 2.29, ASTM E 1710: 1.05 Illumination angle EN 1436: 1.24, ASTM E 1710: Depth of measuring field 3.0 m (from 13.5 m to 16.5 m in front of the receiver) Width of measuring field 5.0 m Measuring distance in front of 15 m the measuring head Mounting height of light outlet approximately 32 cm Mounting height of receiver approximately 60 cm Measuring speed minimum no limit Measuring speed maximum 120 km/h Measuring range R L mcd m -2 lx Measuring range line width Full line width, up to 30 cm; typically 15 cm Driver display 7" Touch-Screen icture interval 50 msec, typically 1.35 m at 27 m/sec Light source LED lamp, 90 Watts continuous, colour temperature ca K Working life of the lamp operating hours Lens focal length 20 mm Output results format CSV files Connection to laptop Gigabit Ethernet Image output Monochrome image stream with superimposed graphics Operating temperature 0 C to 55 C (32 F F) Storage temperature -15 C to 60 C (5 F F) Humidity non condensing Dimensions (L x W x H) 34 x 76 x 49 cm Weight measuring head 40 kg Standards EN 1436 (R L ), ASTM E 1710 (R L ) Table 1: Technical data of the RetroTek-M according to originator s declaration 4 Measurement location 4.1 Comparison with measurements from a portable measuring device The measurements were taken in a darkened hall at the originator s office. 4.2 Comparison of measurements at different speeds The measurements to chapter 2.2 were taken on the motorway M3 between junction 4 (at Clonee) and junction 5 (near Dunboyne) in both directions of travel. GS coordi- 3

4 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation nates for start of loop: , ; for loop turn point: , ; for end point: , The lane width at the test site is about 2.8 m to 3.0 m. The outside lane is dashed, the dash length is at 2 m. The inside lane is continuous. The line widths vary from 15 cm to 22 cm. 5 Test procedure Date of measurement: 15 th June Road conditions: Road and marking surface were dry and clean. 5.1 Comparison with a portable measuring device In the darkened hall, R L was measured from 20 test samples of type I or type II. Definition of type I and type II road markings according EN 1436: Type II road markings are road markings with special properties intended to enhance the retroreflection in wet or rainy conditions, type I road markings do not necessarily have such special properties. The test samples were new, not overrun. In table 2 the material and the dimensions of the samples is described. T: C: Ag/dot: Ag/irr: Ta/lb: Ta/d: thermo plastics (extrusion) cold plastics (2 component material) marking consisting on agglomerates with regular arranged dots marking consisting on agglomerates with irregular arranged elements tape with large beads diamond pattern 4

5 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation Sample no. colour type material dimension (m x m) 1 White I T 1.22 x White I T 1.22 x White I T 2.0 x White I T 2.0 x White I T 2.0 x White I T 2.0 x Yellow I T 2.0 x Yellow I T 2.0 x Yellow I T 1.22 x Yellow I T 1.22 x White I T 2.0 x White I T 2.0 x White I C, Ag 1.5 x White II C, Ag/dot 1.5 x White II C, Ag 1.5 x White II C, Ag/dot 1.5 x White II Ta/d 2.0 x Yellow II Ta/lb 2.0 x Yellow I Ta 2.4 x Yellow II Ta/d 2.0 x 0.15 Table 2: The analysed samples 10 readings were taken for each sample (from the beginning to the end of the sample in equal distances) with the LTL-XL. The arithmetic average value of these 10 readings is shown in column 2 of table 3 as average LTL-XL. Then each sample was positioned in a distance of 15 m in front of the RetroTek-M. The RetroTek-M was mounted on a car according to the dimensions given in table 1. Each sample was arranged successively in three lateral positions: In the line of driving direction (centre) and with an offset of each 1.6 m to the left and to the right hand side. The readings, shown in the columns 3 to 5 in table 3, represent the mean values of R L over the whole area of each sample. In column 6 is shown the average for the readings of the three positions, called as average RetroTek-M. In Column 7 is given the arithmetic average of the averages of the LTL-XL and RetroTek-M values (average of column 2 and 6), called as common average value CA. In column 8 are reported the values Diff RetroTek-M, calculated by the formula Diff RetroTek-M = 100 % (average RetroTek-M - CA)/CA 5

6 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation Figure 1 in the appendix illustrates the measured values for the LTL-XL, the RetroTek-M and the common average values CA values R L (mcd m -2 lx -1 ) average RetroTek-M common Diff RetroTek-M (%) LTL-XL average sample centre left right average RetroTek-M value CA Mean value of all samples Mean absolute deviation Table 3: Measurement results, sorted by ascending R L values for the LTL-XL and the RetroTek-M and the Diff RetroTek-M The measured values for the average RetroTek-M and the CA values provided in table 3 were used to perform a linear regression analysis: R L (RetroTek-M) = CA r² =

7 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation NOTE 1: It is a matter of discussion, if it is reasonable to compare the results taken with the handheld LTL-XL and the RetroTek-M, averaged over the three lateral positions: Driving at night, the real illumination and observation geometry is a very complex threedimensional geometry. In contrast to that the geometry defined in the EN 1436 is a simplified geometry which represents the situation of a motorcyclist driving along a (longitudinal) marking. Therefore one could call the EN 1436 geometry as two-dimensional motorcyclist geometry. This kind of geometry is realised in the LTL-XL and other handheld instruments. The same geometry is also working if the readings are recorded with the RetroTek-M for each of the three described sample position. Therefore it is justified to compare the readings of the LTL-XL with the average of the readings for the three sample positions, measured with the RetroTek-M (see also note 2 at chapter 6.1). 5.2 Comparison of measurements at different speeds Between two junctions on M3 (see chapter 4.2), continuous measurements of R L were taken with the RetroTek-M at four different speeds. In the measurement runs, every effort was made to keep the speed as constant as possible. The nominal and the real mean speeds are given in table 4. nominal speed 50 km/h 70 km/h 90 km/h 110 km/h real mean speed 52.6 km/h 71.1 km/h 93.9 km/h km/h Table 4: Nominal and real speed of the four runs Within the test site a stretch of m was chosen and the measurements were averaged out over a distance of 100 m. These mean values are indicated as M 50, M 70, M 90 and M 110 for the four speeds. For each run therefore 2 markings x 2 directions x 20 values M V = 80 values are available. Tables 5 to 8 show the mean values M V (columns 2 to 5), the resulting overall mean M derived from columns 2 to 5 (column 6) and the percentage variance of the values calculated at the four speeds from the overall mean 100 % (M V -M)/M (columns 7 to 10). For the two means series M V with the largest difference in mean values of all samples (recorded in the last line of tables 5 to 8) the regression line was calculated and shown under each table. Figure 2 in the appendix illustrates as example the results of table 5. 7

8 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation measurement M V : R L mean over 100 m for speed in km/h overall mean M 100 % (M V -M)/M interval M 50 M 70 M 90 M 110 M 50 M 70 M 90 M ,8 70,4 71,3 68,2 69,9-0,18 0,68-2,47 1, ,7 65,7 65,9 65,7 65,8-0,08-0,08-0,08 0, ,1 59,0 59,1 57,2 59,1 3,38-0,17-3,21 0, ,0 62,1 61,6 60,2 61,5 0,85 1,02-2,07 0, ,1 61,2 67,2 59,0 62,4-0,44-1,88-5,41 7, ,0 62,7 62,0 61,6 62,3 1,08 0,60-1,16-0, ,3 57,8 59,5 57,7 58,3-0,04-0,90-1,07 2, ,6 61,7 62,4 62,2 62,2 0,60-0,84-0,04 0, ,2 66,4 67,9 64,0 66,1 0,11 0,42-3,21 2, ,3 56,3 56,1 55,0 56,2 2,00 0,22-2,09-0, ,9 58,6 59,8 59,6 59,2-0,55-1,06 0,63 0, ,2 60,1 62,5 60,6 61,1 0,16-1,64-0,82 2, ,7 59,2 58,7 56,7 58,6 1,92 1,07-3,20 0, ,3 48,8 48,3 48,2 49,2 4,37-0,71-1,93-1, ,6 62,1 61,6 62,5 61,7-1,78 0,65 1,30-0, ,3 58,7 57,7 60,1 58,7-0,68 0,00 2,39-1, ,2 57,4 57,3 57,5 57,6 1,04-0,35-0,17-0, ,1 56,1 55,2 56,8 55,6-2,61 0,99 2,25-0, ,1 64,5 62,9 64,9 63,9-1,17 1,02 1,64-1, ,5 84,0 83,4 83,5 83,1-1,93 1,08 0,48 0,36 Mean value of all samples Mean absolute deviation 61,8 61,6 62,0 61,1 61,6 1,25 0,75 1,29 1,78 Table 5: R L values depending on speed, mean M V over 100 m and the values 100 % (M V -M)/M for the run going north, left marking Linear regression for the means M V with the largest difference in mean values of all samples (recorded in the last line) = M 90 - M 110 : M 90 = M 110 r² =

9 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation measurement M V : R L mean over 100 m for speed in km/h overall mean M 100 % (M V -M)/M interval M 50 M 70 M 90 M 110 M 50 M 70 M 90 M ,3 86,9 86,8 88,5 87,4-0,09-0,54-0,66 1, ,1 88,1 89,3 89,4 88,7-0,70-0,70 0,65 0, ,5 94,1 95,4 95,8 95,0-0,47-0,90 0,47 0, ,8 105,2 105,2 106,4 105,4-0,57-0,19-0,19 0, ,2 105,8 106,0 106,5 105,9-0,64-0,07 0,12 0, ,1 100,4 103,0 101,7 101,6-0,44-1,13 1,43 0, ,9 89,0 89,1 89,6 89,2-0,28-0,17-0,06 0, ,1 90,6 90,1 92,2 90,8-0,72-0,17-0,72 1, ,4 95,7 95,8 97,8 96,2-0,81-0,49-0,39 1, ,0 84,0 83,8 84,1 84,0 0,03 0,03-0,21 0, ,1 91,2 91,3 91,8 91,4-0,27-0,16-0,05 0, ,0 91,9 91,2 92,9 91,8-0,82 0,16-0,60 1, ,2 93,0 93,7 94,0 93,5-0,29-0,51 0,24 0, ,6 90,8 91,1 91,5 91,0-0,44-0,22 0,11 0, ,8 97,8 98,1 98,3 98,3 0,56-0,46-0,15 0, ,3 100,2 100,1 100,7 100,3-0,02-0,12-0,22 0, ,5 103,4 104,2 103,1 103,6-0,05-0,14 0,63-0, ,7 102,7 102,7 104,2 103,3 0,36-0,60-0,60 0, ,6 107,6 107,0 109,2 107,6-0,93 0,00-0,56 1, ,7 114,4 125,1 116,4 117,7-2,51-2,76 6,33-1,06 Mean value of all samples Mean absolute deviation 96,6 96,6 97,5 97,7 97,1 0,55 0,48 0,72 0,78 Table 6: R L values depending on speed, mean M V over 100 m and the values 100 % (M V -M)/M for the run going north, right marking Linear regression for the means M V with the largest difference in mean values of all samples (recorded in the last line) = M 70 - M 110 : M 70 = M 110 r² =

10 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation measurement M V : R L mean over 100 m for speed in km/h overall mean M 100 % (M V -M)/M interval M 50 M 70 M 90 M 110 M 50 M 70 M 90 M ,8 63, ,8 62,9-0,20 0,28 0,12-0, ,8 72,0 73,2 72,8 72,7 0,14-0,96 0,69 0, ,9 73,8 74,6 74,3 74,7 1,67-1,14-0,07-0, ,1 73,9 74,3 75,0 74,3-0,30-0,57-0,03 0, ,6 75,8 75,7 76,7 76,2 0,52-0,52-0,66 0, ,0 78,6 78,6 79,0 78,8 0,25-0,25-0,25 0, ,1 80,4 80,2 79,5 80,3 1,00 0,12-0,12-1, ,8 80,1 78,5 78,0 79,1 0,88 1,26-0,76-1, ,9 77,9 78,3 78,5 78,2-0,32-0,32 0,19 0, ,2 87,3 88,5 88,0 88,3 1,08-1,08 0,28-0, ,3 94,6 97,4 97,1 96,1-0,83-1,56 1,35 1, ,3 84,0 86,5 84,7 85,6 1,96-1,90 1,02-1, ,5 77,0 78,1 79,3 78,2 0,35-1,57-0,16 1, ,0 77,9 78,1 79,0 78,5 0,64-0,76-0,51 0, ,5 87,0 87,3 87,0 86,7-1,38 0,35 0,69 0, ,4 92,9 96,1 93,4 93,5-2,19-0,59 2,84-0, ,2 88,4 91,1 88,1 89,5 0,84-1,17 1,84-1, ,4 93,8 98,4 96,6 95,6-2,25-1,83 2,98 1, ,5 94,3 93,3 93,2 93,8 0,72 0,51-0,56-0, ,8 103,6 102,1 102,1 102,7 0,15 0,93-0,54-0,54 Mean value of all samples Mean absolute deviation 83,4 82,8 83,7 83,3 83,3 0, ,78 0,70 Table 7: R L values depending on speed, mean M V over 100 m and the values 100 % (M V -M)/M for the run going south, left marking Linear regression for the means M V with the largest difference in mean values of all samples (recorded in the last line) = M 70 - M 90 : M 70 = M 90 r² =

11 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation measurement M V : R L mean over 100 m for speed in km/h overall mean M 100 % (M V -M)/M interval M 50 M 70 M 90 M 110 M 50 M 70 M 90 M ,8 66,6 66,7 66,8 66,7 0,11-0,19-0,04 0, ,2 73,8 73,2 74,1 73,6-0,51 0,31-0,51 0, ,9 84,8 84,3 84,8 84,5-0,65 0,41-0,18 0, ,4 94,8 94,8 94,4 94,6-0,21 0,21 0,21-0, ,8 98,4 99,5 98,0 98,4-0,64-0,03 1,09-0, ,6 105,6 107,3 105,9 106,1-0,47-0,47 1,13-0, ,2 107,7 108,2 108,1 107,8-0,56-0,09 0,37 0, ,3 116,7 117,2 117,8 117,3 0,04-0,47-0,04 0, ,4 108,2 107,6 109,0 108,1-0,60 0,14-0,42 0, ,1 115,6 113,7 113,5 114,2-0,11 1,20-0,46-0, ,9 125,4 124,5 125,3 124,8-0,70 0,50-0,22 0, ,3 122,6 119,9 120,3 121,3 0,85 1,09-1,13-0, ,6 113,8 114,0 112,2 113,4 0,18 0,35 0,53-1, ,3 110,8 110,4 110,5 110,3-0,86 0,50 0,14 0, ,2 111,0 110,7 111,1 111,0 0,18 0,00-0,27 0, ,9 107,2 106,8 106,8 106,9-0,02 0,26-0,12-0, ,6 118,8 118,9 119,1 118,9-0,21-0,04 0,04 0, ,8 117,2 116,7 117,4 117,0-0,19 0,15-0,28 0, ,5 112,5 113,3 112,9 113,3 1,06-0,71 0,00-0, ,5 125,5 125,5 126,3 124,7-2,57 0,64 0,64 1,28 Mean value of all samples Mean absolute deviation 106,3 106,9 106,7 106,7 106,6 0,54 0,39 0,39 0,46 Table 8: R L values depending on speed, mean M V over 100 m and the values 100 % (M V -M)/M for the run going south, right marking Linear regression for the means M V with the largest difference in mean values of all samples (recorded in the last line) = M 50 - M 70 : M 50 = M 70 r² = In table 9 are listed the highest positive and negative deviations 100 % (M V - M)/M of M V for all runs and all markings. 11

12 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation Table Maximum 100 % (M V -M)/M next worse Table 9: Highest positive and negative deviations 100 % (M V -M)/M for all M V 6 Assessment of the measurement results 6.1 Assessment of comparison measurements with a portable measuring device Table 3 shows that the measured values of the RetroTek-M differ from the common average value of both measuring systems (LTL-XL and RetroTek-M) at most with % / %. According to the validation process of the Federal Highway Research Institute (BASt) for road markings and measuring devices a variation of about ± 7.5 % can appear in at most 5 % of all comparative values, the RetroTek-M results are complied with this regulation. Averaged over all 20 samples, both measuring systems provide practically identical measured values: LTL-XL: mcd m - ² lx -1 ; RetroTek-M: mcd m -2 lx -1 ; the coefficient of determination r² amounts to This confirms that the measuring system RetroTek-M provides, within the scope of an acceptable measuring accuracy, the same measured values of the coefficient of retroreflected luminance R L as a portable, handheld measuring device. NOTE 2: In note 1 (chapter 5.1) was stated that it is justified to compare the readings of the LTL-XL with the average of the readings for the three sample positions, measured with the RetroTek-M. But additional calculations (not reported in this certificate) have shown that even at the comparison of the readings of the LTL-XL with the readings of the RetroTek-M, taken for each sample separate position, the limit of 7.5 % is undercut in all cases. 6.2 Assessment of comparison of the measurements at different speeds Tables 5 to 8 indicate that the measured values, averaged over a length of 100 m, are nearly identical at the four measuring velocities. The investigation of the percentage deviation from the common average value (see table 9) reveals that only in one case of the 320 measurement values (red marked in table 5 and 9) = 0.3 %, the measurement value exceeds the limit of 7.5 %. Therewith BASt regulation is fulfilled (also for this test in at most 5 % of all comparative values a variance of more than ± 7.5 % is allowed). The coefficients of determination for the difficult measuring conditions in moving traffic are acceptable. 12

13 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation The coefficient of retroreflected luminance R L can be detected with a good measuring accuracy by the measuring system RetroTek-M, independent of the measuring velocity. 7 Overall assessment The deviations of the measurement results specified under section 5 for comparison measurements are low overall, especially considering that the difficult measuring conditions (different measuring areas, uneven marking surface, non-homogenous structure of the marking surface, non-homogenous bead distribution) cause inaccuracies that are not attributable to device inaccuracy. By meeting the conditions specified in section 6, the RetroTek-M Mobile avement Retroreflectometer is hereby deemed to be well suitable for the dynamic measurement of the coefficient of retroreflected luminance R L of road markings according to the measuring geometry and measuring conditions given in the European Standard EN 1436 and delivers the same results as a portable retroreflectometer. The measuring results are independent of the measuring speed and are not influenced by the kind and form of the road markings. (Dr. H. Meseberg) Chairman of Strausert e.v. This test certificate has been issued to the best of my knowledge and belief. 13

14 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation Appendix R L (mcd m -2 lx -1 ) average LTL-XL average RetroTek-M Common average value CA samples Figure 1: Measured values R L for the LTL-XL, the RetroTek-M and the common average value CA (red line) for 20 test samples 14

15 rüf-, berwachungs- und ertifizierungsgemeinschaft Construction roducts Regulation 90 R L (mcd m -2 lx -1 ) km/h 70 km/h 90 km/h 110 km/h mean m interval Figure 2: Measured values R L for the RetroTek-M at the M3 averaged over 100 m for four different speeds, and the average for all speeds (red line). Run going north, left marking 15