Road Markings/Centre Line
| Centre Lines | |||
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| White lining at the former end of the A9 dual carriageway at Luncarty | |||
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| To : | present | ||
| Variants : | Dashed White, Single White, Double White | ||
Roads with enough width for more than a single lane for traffic predominantly have a Centre Line separating traffic flows. In the UK there are three basic sets of lines used, with some variations.
Dashed White Lines
The Dashed White Line is used to identify the centre of the carriageway and permits overtaking. However, the use of these lines does not indicate that it is safe to overtake. Different lengths and spacings of the dashes are used to indicate potential hazards, and the lines can also be used to surround central turning lanes and other features on single carriageway roads. On dual carriageways and motorways, similar lines are used as lane dividers.
Single White Lines
The term Single White Line is a bit of a misnomer, as it is in fact two parallel lines used to identify the centre of the carriageway. One of these lines is solid and the other dashed, allowing overtaking in a single direction only. They are regularly used on the changeover from Dashed to Double White Lines, and also on sections of S3 carriageway to only permit overtaking uphill for instance.
Double White Lines
The Double White Line is used to identify the centre of the carriageway and bans overtaking. They are widely used on bends, blind summits, to protect junctions and in many locations where there have historically been accidents.
Textured Centre Lines
Centre lines were originally all painted in smooth white paint which made little or no impact on the driver other than visually. However, in recent years textured paints have been developed which provide both an audio clue and vibration to the vehicle to identify their presence. These painting techniques were first used on Verge Lines, but have since been refined for use on centre lines. The texture therefore warns drivers that they have crossed the centre lines, and it the transgression was accidental, they are easily alerted and return to the correct lane. In certain vehicles, drivers have commented that the steady vibration is actually quite a pleasant sensation, encouraging them to run a tyre along the textured line when it is safe to do so!
Although this texturing is highly effective when first laid, it does seem to survive to different extents in different locations. While some sites still seem to be effective after a year, others have been worn down considerably after just a few months, substantially lessening the effect on the driver.
Implementation
The first identified use in Scotland was on the A87 climbing up from Invergarry village to the Glen Garry viewpoint. They were painted in 2017 or 2018 and appear to have been a trial by Transport Scotland, although no details of the trial have been found so far. It was evidently deemed successful, however, and from summer 2020, all resurfacing projects in Transport Scotland's North West area, and most in other areas have had the new textured lines installed upon completion. This applies to verge lines as well as centre lines. In most instances where the white lining has been replaced without resurfacing, textured lines have also been used.
| Road Markings/Centre Line | ||||||||||||
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