Around a third of lane one road markings on the major road network (MRN) could be classed as either defective or absent completely, a major new inspection survey has found.
The independent survey also discovered that the contrast between the vast majority of lane one markings and the pavement surface was below that required for in-vehicle sensors and autonomous vehicles.
Commissioned by leading trade body the Road Safety Markings Association (RSMA), the survey was undertaken independently by Reflective Measurement Systems Ltd of Ireland, using its RetroTek D technology, which allows data to be collected by a vehicle travelling at normal speed.
It analysed more than 2,100km of the MRN, which comprises the most vital roads, managed by local authorities, connecting major conurbations and motorways and carrying high volumes of fast-moving traffic.
Unlike the MRN, the strategic road network (SRN), managed by National Highways, operates in accordance with CS 126 - Inspection and assessment of road markings and road studs, found within the Design Manual for Roads and Bridges.
Under CS 126, anything below 80 millicandelas (mcd) retro-reflectivity is classed as a defect, because it has reached the threshold level for interventions.
The survey analysed the left (edge line) and right (centre line or lane two divide if a dual carriageway) of lane one. It found that 36.15% of the MRN markings in lane one (left) were below 80mcd and 26.40% on the right. This means in total, roughly 31.3% of the lane one road markings on the MRN could be considered defective or not present at all.
The RSMA also highlighted that ‘it is generally accepted that for machine systems within vehicles to be able to ‘read’ road markings a minimum contrast of 3:1 is required’.
The survey found 85.82% of the lane one left edge marking was below 3:1 contrast, and 72.73% below 3:1 on the right – meaning in total 79.275% was below the generally accepted level of machine reading.
Outgoing chief executive of the RSMA, Stu McInroy, said: 'We were interested in gathering data on both retroreflectivity and contrast - retroreflectivity, because it could be reducing the number of those killed and injured on our roads today, and contrast, as it will be key to successfully migrating increased levels of autonomy in vehicles from the SRN to wider subnational networks.'
While the MRN does not operate to the same standards as the SRN, part of the original intention behind the now somewhat nominal MRN was to raise standards on these local roads closer to the national level.
The RSMA has argued the same standards should be adopted on the SRN and MRN and submitted evidence to the transport select committee outlining its case.
It wrote: ‘In applying CS 126 to only the SRN an imbalance of standards and uniformity is created between the SRN and other networks.
'The RSMA has attempted to correct this imbalance through the publication of STANSPEC 2022. STANSPEC 2022 deals with the supply and installation of road markings on LA [local authority] road networks and contains the intervention and assessment aspects of CS 126, allowing for road markings to be inspected more frequently and maintained to a higher standard than they would have otherwise been. However, while this standard fills a void, it is voluntary; the RSMA has no power to force LAs to adopt it.’
The RSMA has also noted in its evidence to MPs, 'unless and until Government mandates the application of CS 126 to the MRN, the UK’s operation of increasingly automated vehicles shall remain confined to the SRN, or worse still, the absurd scenario where a semi-automated vehicles could operate in one particular county but be unable to operate once they reach a county boundary due to a lack of consistency in road marking standards'.
Mr McInroy stressed the survey sought to inform discussion around issues like whether there should be a single authority responsible for the MRN, and whether the MRN is ready in the future for increasing levels of autonomy.
'Without appropriate answers to such questions the UK public will have access to very capable vehicles but without the infrastructure which they need to operate such vehicles will be little more than expensive garden ornaments,' he said.
The RSMA hopes to publish a full report of the survey in the spring of 2024. These initial results were revealed at the RSMA's annual conference in February.
