Method of applying a thermoplastic marking to a road surface, which marking is provided with indents that during application of the marking to a road surface are used as an indicator that the thermoplastic marking has been heated to such an extent that it has become sufficiently liquefied to adhere to the road surface, the method comprising the steps of: i. heating and extruding a thermoplastic material composition comprising a) thermoplastic material constituting between 10-90% by weight of the thermoplastic material composition, b) filler material, and c) pigment, ii. extruding the thermoplastic material composition from an extruder onto a conveyor, the thermoplastic material composition having an exit temperature (T exit) of between 100-190 °C when leaving the extruder, iii. controlling a surface temperature of a first surface of the thermoplastic material composition to a temperature (T es) being 0-180 °C lower than the exit temperature (T exit) and being between 20 °C lower than the melting temperature (T m) of the thermoplastic material and 10 °C, iv. introducing by force a plurality of stamping tools into the extruded and thus tempered thermoplastic material composition to a predetermined depth (d) from said first surface of the extruded thermoplastic material composition to form indents, wherein the thermoplastic material composition is extruded to a material thickness (t) of between 1,5 and 8 mm, and wherein the stamping tools are introduced from the first surface to a depth (d) within 15-100% of the material thickness (t), v. cooling and cutting the stamped material to desired shapes for application, and vi. applying the indented thermoplastic marking material to a road surface, wherein an indication of sufficient heating of the thermoplastic marking material for it to become liquefied to adhere to the road surface provided when the indents disappear due to the flow of the heated thermoplastic material to form a smooth upper surface. i. heating and extruding a thermoplastic material composition comprising a) thermoplastic material constituting between 10-90% by weight of the thermoplastic material composition, b) filler material, and c) pigment, a) thermoplastic material constituting between 10-90% by weight of the thermoplastic material composition, b) filler material, and c) pigment, ii. extruding the thermoplastic material composition from an extruder onto a conveyor, the thermoplastic material composition having an exit temperature (T exit) of between 100-190 °C when leaving the extruder, iii. controlling a surface temperature of a first surface of the thermoplastic material composition to a temperature (T es) being 0-180 °C lower than the exit temperature (T exit) and being between 20 °C lower than the melting temperature (T m) of the thermoplastic material and 10 °C, iv. introducing by force a plurality of stamping tools into the extruded and thus tempered thermoplastic material composition to a predetermined depth (d) from said first surface of the extruded thermoplastic material composition to form indents, wherein the thermoplastic material composition is extruded to a material thickness (t) of between 1,5 and 8 mm, and wherein the stamping tools are introduced from the first surface to a depth (d) within 15-100% of the material thickness (t), v. cooling and cutting the stamped material to desired shapes for application, and vi. applying the indented thermoplastic marking material to a road surface, wherein an indication of sufficient heating of the thermoplastic marking material for it to become liquefied to adhere to the road surface provided when the indents disappear due to the flow of the heated thermoplastic material to form a smooth upper surface.