1. TESTING NIGHT VISIBILITY OF ROAD MARKINGS AS FACTOR OF ROAD TRAFFIC SAFETY

2. INTRODUCTION
Modern traffic demands the safe movement of vehicles under normal conditions and especially at night and in reduced visibility (fog, rain, sleet, etc.).
Quality and quantity of participants visual guidance in traffic directly depends on the visibility and the reflective properties of road markings are of crucial importance.
Using the latest methods and procedures of testing road markings a high and constant quality level can be achieved , and thus the security level of individual roads can be raised.

3. ROAD MARKINGS TESTING
The reflective properties of road markings are of crucial significance, and represent one of the main factors increasing the safety of participants in road traffic.
Road markings are made in accordance with the Regulations on traffic signs and equipment on roads and Croatian and EU standards.
Road markings have to respond to Guidelines and technical requirements for carrying out works on the renewal of road markings.

4. Reflection types: Diffuse reflection : Retroreflection :
Daily visibility
Night visibility

5. Night visibility: retroreflection theorya e
30m
glassbeads
Light reflection
Road markings are visible at night due to a spherical retroreflection

6. STATIC AND DYNAMIC METHODS OF TESTING DAY AND NIGHT VISIBILITY OF ROAD MARKINGS
One of the most important elements for testing the quality of road markings is testing day and night visibility of road markings. These tests can be done in two ways:
method for static test of road markings reflection (daytime and nighttime visibility)
dynamic method for testing retroreflection of road markings (nighttime visibility)

7. STATIC TEST OF REFLECTION OF ROAD MARKINGS METHOD
Static testing of road markings can be done by using the retroreflectometer ZEHNTNER ZRM Measurements are performed according to European standards EN 1436, Materials for Road markings- Characteristics required for road users.
Slika 1. Device for measuring retroreflection of road markings
ZEHNTNER ZRM 6013.

8. Static testing of day and night visibility can be done by two methods:
According to "Kentucky" method,
In the future, according to new guidelines and technical requirements of the test procedure, ie. measurement and valuation of derivative road markings shall be carried out in accordance with the German regulation ZTV M 02

9. KENTUCKY METHOD
Road

10. Microlocation measurements

11. METHOD ACCORDING TO GERMAN REGULATION ZTV M 02
The length of longitudinal markings done in one day
(km)
The length of the other markings done in one day (m2)
Number of measuring sections
< 1
< 120 1
1 - 5 2
>5 - 10
> 3
> 10
> 1200 4

12. Section of road performed with one team in one day
Measuring sections selected by the principle of coincidence
Microlocation measurements

13. DYNAMIC METHOD FOR TESTING RETROREFLECTION OF ROAD MARKINGS
Dynamic method for testing retroreflection of road markings involves the measurement of night visibility with dynamic measuring device throughout its length.
It can be performed with dynamic retroreflectometer ZEHNTNER ZDR 6020 which is installed on a vehicle measuring and thus allows continuous measurement of the night visibility (Rl) road markings while driving vehicles.
Principle of measuring visibility at night ZEHNTNER ZRM's is the same as in static measuring device, ie at measuring the night visibility of the device measures retroreflection of light rays from the study area at an angle of °, the angle of input light of 1.24 ° and at a distance of 30 m at short lights.

14. Road
Section of road performed with one team in one day
Section measured with dynamic retroreflectometer

15. Figure 2: Measurement vehicle with ZRM 6020 devices

16. The device ZEHNTNER ZDR 6020 has following features:
Measurement of road markings night visibility Rl in the day and night conditions
It is suitable for measuring all kinds of night visibility of road markings, and profiled benchmark to 9 mm
It is suitable for measuring night visibility in dry and wet conditions
Has an integrated surveillance cameras, takes pictures automatically every 25 m, and also has the ability of shooting photos manualy
It has a built-in GPS system that captures the movement of vehicles and has sensors for measuring temperature and humidity
Has the possibility of sending and processing data in a RetroGrabber software package and the ability to switch data into .xls format that allows statistical analysis of measured values

17. The ZDR 6020 Dynamic Retroreflectometer RL System consists of several elements that are necessary for operation:
Measuring head
Cockpit installation
Laptop
Carbox
Wiring of the car
Slika 3: Izgled postavljene mjerne glave na vozilo

18. The laptop is used to operate the measuring system.
The laptop is used to operate the measuring system.
With its installed Retro-Grabber software it is able to communicate with the measuring head and record measured data to its hard drive.
For measuring, the laptop needs to be in the docking station in the car.
Slika 4: Unutrašnjost mjernog vozila

19. Measurements are done in a way that the measuring vehicle moves along the road surface and reads the coefficient of road markings retroreflection along which it moves.
Before the measurements it is necessary to select the length of the measurement interval at which the device will measure the average value of each measurement section (ie the length of the measurement interval of 100 is set, this means that the device while measuring the shares for every 100 m will give an average value of visibility in this night measurement interval).
Our experience shows that the optimal length of measurement interval is 50 or 100 m.
Slika 5: Prikaz zaslona vozača u trenutku mjerenja

20. The software package that is installed on a laptop computer performs the following operations:
Collecting night visibility values obtained from the measuring head
Calculate the value of each sensor signal which is reflected by the road markings
Verification of the obtained values with regard to the set "filters“
calculating the average values obtained at set intervals
Storing calculated values in a separate file along with other information about the measured road section (images, audio, GPS recordings ...).
Slika 6: Prikaz rezultata mjerenja i kontrola
nakon mjerenja

21. The data on temperature, humidity, wind speed ...
Photos
GPS coordinates
RL values
___________
_________
_________
_________

22. CONCLUSION
Testing road markings with a measurement vehicle equipped with dynamic retroreflectometer offers the possibility of obtaining a continuous measurement results for the whole section intended to be measured, in a short time.
At the same time, the process of testing, measuring vehicle with dynamic retroreflectometer performs accurately, and disruption of traffic is reduced to a minimum (the operating speed of testing the quality of road markings is 70 km / h).
All the above suggests the possibility of systematic testing the quality of road markings on the Croatian roads and getting quality results for individual sections which represents a solid basis for the optimal maintenance plan, and savings in the maintenance of road markings.

23. CONCLUSION Tako dobiveni rezultati ispitivanja omogućuju:
učinkovitije održavanje pojedine prometnice,
pregled kritičnih mjesta,
određivanje prioriteta održavanja,
optimiziranje redoslijeda nanošenja oznaka na kolnik.
Primjenom ove mjerne metode moguće je organizirati sustav održavanja prometnica koji omogućuje konstantnu visoku razinu vidljivosti oznaka na kolniku što utječe na sigurnost vozača, posebice tijekom vožnje u nepovoljnim vremenskim uvjetima.

24. THANK YOU FOR YOUR ATTENTION!
Fakultet prometnih znanosti
Zavod za prometnu signalizaciju
Vukelićeva 4, Zagreb
Anđelko Ščukanec, Ph.D. -
Mario Šafran, Ph.D. –
Kristijan Rogić, Ph.D. –
Darko Babić, M.Sc. –
Siniša Radulović, B.Sc. –
Tomislav Rožić, B.Sc. –