The text of this article taken from the Estonian Highways magazine TeeLeht was written by Tiit Kaal of ERC Consulting who has used the RetroTek-M mobile retroreflectometer to assess the retro-reflectivity of road marking on the Estonian road network 2017 and 2018. This is a translated version of the text and the full version in Estonian can be read on page 28 and 29 of the magazine which can be read HERE.
Tiit Kaal: It is difficult to renew road markings on time without adequate data on their condition
Tiit Kaal from ERC Consulting Ltd, who measured the retroreflectivity of road markings on main state roads and basic roads in Estonia, considers the project to be necessary, as good quality road markings are an important tool for ensuring road safety in our Nordic country climate.
How did the measuring take place?
Konesko AS built a frame to attach in front of the car, so the RetroTek-MTM measuring device could be attached onto with bolts. We installed the device onto the frame with the help from the representatives of the device manufacturer, we also made the necessary pre-measure calibration operations with them. When installing the device, it was necessary to follow the instructions very precisely – the device had to be at a certain distance from the car’s centre, at the correct height from the road and at a right angle. The device was pretty heavy – about 50kg, but the mass is necessary for the device to be as stable as possible during the measurement. The advantage of the measuring device that we rented from the Irish was that we were able to measure both the right and left lines of the lane, and do it at a normal driving speed. However, I had to keep the speed a little below the limit, in order to avoid unnecessary overtaking, as it would have distorted the measurement results. The measurement process in itself is automated and does not require much human intervention.
How many kilometres did you collect?
Under the terms of the contract, the retroreflectivity of all longitudinal lines on main state and basic roads had to be measured. There are 1609 km of main roads in Estonia, and we accumulated well over 3500 km measuring all the lanes. In addition, we had to measure the road markings on turning lanes, which made the total distance covered to 15 000 km. There are 2412 km of basic roads in Estonia and the measured kilometres ended up being just under 5000. We didn’t have to measure the turning lanes on basic roads.
The device could only be used during the night. How did you work in this mode?
Last year I started measuring at the end of April, as soon as the weather allowed it, and the work lasted until mid-June. I got used to nightshifts fairly fast. I simply had to take into account that as the summer came closer, the shorter the nights. On the Tallinn-Tartu-Võru-Luhamaa road, I could only measure one end before the sunrise, and then had to wait until the next night to continue.
Since we had some experience working with the device last year, we got the measurement system set up this year early and started with the work in April according to the terms of the contract. The spring was quite variable and rainy, yet we finished with the measurements in the middle of May, thus the rapid shortening of the night did not affect us much this time.
Did you encounter any problems while using the device?
There were no major problems and the device worked this whole time without any issues. The weather caused some difficulties as you can only measure on dry roads. On some nights, a thick mist caused issues as the lights and camera on the device don’t have any windscreen wipers. Additionally, the devices was sensitive to insects, so from time to time it was necessary to stop and clean the glass surfaces. Fortunately, the nights were fairly cool so the insect problem wasn’t that big.
How does the device output measurements?
Measurement results can be issued at different measurement points through data processing done at the office. Our project presented the results in 100-meter-increments (similar to other road surface condition data). For each measured 100 m section of the measured lane, the measurement time (date and time), coordinates (to get a good overview of the status of road markings in the map application), the retroreflectivity value on the left and right line marking, air temperature and humidity, and the driving speed were provided. All measurement results were linked to the official road address which allows the data to be entered into the road register.
What is the condition of road markings on main and basic roads in Estonia?
The assessment depends on the set requirements. The light reflection requirements for road markings used in Estonia had so far not been established, but at the beginning of the project the specified condition classes were determined. Based on that, about ¾ of the measured road markings on main state roads corresponded to the condition class agreed upon beforehand. On the other hand, based on the limit values used in Finland, about 50% of the road markings on main roads would need immediate update. We do not have the results from the measurements done on basic roads as the data processing is still ongoing but it’s safe to say that the condition on those roads is probably a grade worse than compared to main roads.
It is worth noting that modern road marking materials can be very effective: on freshly repaired road section of road no.10 near Kuressaare, the RL value was in parts well over 300 mcd/m2/lx. It would be interesting to find out how the marking has lasted throughout use.
On the main roads it was noticeable that there was a surprising amount of road sections without any road markings. Those road sections were under repair works in 2016 and apparently winter came along before the line markers made their way there. Due to our climate this situation is likely to be inevitable but it is still problematic in terms of road safety. In addition to the lack of lines on roads, these road sections endanger road users as the texture and grip properties are not completely developed. The Road Administration should find a sensible solution for the temporary marking of lanes if the markings cannot be printed on roads on time.
On the basic roads it was noticeable that lots of road sections didn’t have any type of road markings, and even some signposts were missing. Road users who make the transition from well-marked roads to roads without any markings can feel a bit uncertain. It was also noticeable that road marking depends on the area. There are places where moving from one region (care district, county etc.) to another and the road marking switches from only being on the edges of the road, to being only in the middle, even though the characteristics of the road haven’t changed.
Is this kind of work necessary from the perspective of a consultant?
In reality, we did not have a precise overview under what state the road markings on our roads are and where it needs renewal. The more data you collect, the more detailed overview will be generated. As we have long dark periods with bad visibility, the lines on the roads help road users to better control their vehicles and stay safe. It is only positive that this type of project took place and it should definitely be continued.
It is also possible to save a lot of money as the measurement results show where and when the road markings need to be renewed. The whole process becomes systematic and can be monitored and scheduled in time. When measuring the road markings with a handheld unit at single points of the road or simply by eye, you cannot get a precise overview of the state of the markings, and the danger of using markings that are in poor condition is very big.
It’s like many years ago when the road repair works were decided by driving people along the road and then they discussed based on the feel whether a specific road should go under repair works or not. Now that we have accurate and objective numerical values, we can plan roadworks much more precisely. That can also be seen from the results – the overall condition of roads is improving everywhere every year. We can plan work early and, if necessary, apply lightweight (read: cheaper) repairs to ensure a proper condition of the road.
Therefore, it is important that the road marking measurement data is entered in the road register database and in addition, data on the type of markings, their characteristics and time of instalment are also there.
A third independent party could also take continuous measurements of road markings reflectivity, as it is the case, for example, with the checking of condition of new pavements. This would ensure homogeneous condition of road markings across the entire road network.
What was most surprising during this project?
Answered by Tiit’s wife Luule Kaal who is working as a consultant in ERC Consulting Ltd.
In the beginning when Tiit arrived home early in the morning after working during the night, he spoke excitedly that he saw this or that wild animal. After a couple of weeks he said “there are a lot of wild animals”. And after that “it’s a damn zoo!” Only once when he saw a bear he got excited again. We can draw one conclusion from this: since we rarely drive during the night we do not think about the danger of wildlife running in front of our vehicles. Therefore, we should be careful and not rush when driving at night. The traffic may be light at night time but the wildlife in Estonia plays its part.