What Different Types of Road Markings Are Used?
A variety of lines are used to make traffic safe and efficient. Solid lines, dashed lines, wide lines, double lines, multiple color lines and diagonal lines are some of the types of road markings used. Numbers, letters and symbols/icons may also be used to instruct drivers. The use of lines and symbols as well as the interpretation by drivers and users of course depend on the regulations in that country or region.
Road markings are an essential part of ensuring a new road to protect and guide drivers. However, signs and signals are also employed to make sure that instructions are as clear and concise as possible.
How Is the Road Line Painting Applied?
The road line painting which typically consists of thermoplastic resin is applied using specialized road marking vehicles. These vehicles distribute the paint at the right amount and at the right pace in order to ensure that the lines have the correct length and thickness. Road marking vehicles may have an internal heater to heat up the thermoplastic paint which is a solid powder at room temperature. The plastic may also be heated externally and then loaded onto the vehicle which will keep the plastic in a fluent state until applied to the road.
Even though a computer is often used to ensure a correct distribution of the paint, the manual control of the marking vehicle still requires a lot of skill and expertise on the part of the steersman. Once applied, the thermoplastic is very hard to alter or erase. The paint is very durable as it must be able to withstand many years of changing weather conditions as well as the tear from vehicles on the road.
Other types of road line paint include cold plastic paint and two-component paint. However, thermoplastic paint is most commonly used due to its durability.
What Road Marking Equipment Is Needed?
The road marking process can be divided into two types of marking; pre-marking and permanent marking. The permanent markings, using resilient materials such as thermoplastic resin, need to be 100% accurate when applied. Otherwise, removing and re-arranging painted lines will drive up costs and project execution time. This is why pre-marking is necessary.
The pre-marking process has been a manual process for a long time, requiring land surveying skills to stake out the lines using GPS rods and/or total stations. For a new highway section, many lines need to be accurately marked down to a few centimeters’ precision and sometimes even below that. A new stretch of highway including several lanes and different line types can easily take several days to set out, often leading to mental and physical fatigue for surveyors.
Once the road marking positions have been staked out by surveyors, road marking crews often need to extend the lines using strings, tape measures and spray cans so that it is absolutely clear where the permanent markings are to be painted.
Positioning and painting the pre-marked lines can also be done automatically, using a road marking robot for pre-marking. The design of the road markings (position, line type, line length, intervals etc.) is typically already determined in the design phase and is available as two- or three-dimensional data. This is very often a DWG file which contains all the necessary information to place the lines. The robot is able to use this data and mark out the lines using the attached spray can.
Efficiency and Safety in Road Construction
In order to ensure high precision and accuracy, the robot uses GPS satellite signals as well as RTK correction signals to pre-mark the lines down to centimeter accuracy. The robot can also be used with a total station for even greater accuracy. Automating the pre-marking phase can save road marking companies and land surveyors a lot of critical time and allow them to complete more work faster and in a more efficient way. Furthermore, land surveyors who need to survey the different road layers during construction can also use the robot for high-precision as-built surveys using a total station.
The road marking robot can work un-aided for 8 hours, completing up to 30 km (18.6 mi) miles in one shift. One of our road marking customer cases evaluated the speed of the robot compared to that of a road marking crew. Pre-marking 1 km (0.6 mi) took 6 man hours for the crew and only 17 minutes for the robot. This is both due to the speed and accuracy of the robot as well as the fact that locating the position of the lines AND marking out the lines is all done in one step when using a robot. This naturally leads to high efficiency gains for road marking companies who can complete the pre-marking phase much faster and allow the permanent marking to begin.
In addition, refurbishments and maintenance work on existing roads with live traffic can be a dangerous place to work for road marking crews and surveyors. Using a robot allows human personnel to be removed from hazardous work places and to control the robot from a safe distance.