The road line painting, which typically consists of thermoplastic resin, is applied using specialised 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 fluid 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.