Around half of British road markings are barely visible, a new survey has found.
Markings on Scottish and Welsh roads were particularly bad, the survey by the Road Safety Markings Association (RSMA) indicated.
The association looked at 483 miles of British roads, including major English roads managed by the Highways Agency and local authority routes.
The survey showed that 50.6% of road markings were barely visible, with 23% of roads falling into the "emergency repairs" bracket.
Fewer than 7% of markings scored the highest rating. This compared with a survey 12 months earlier on the UK's most dangerous roads which showed that 23% of centre lines qualified for the highest rating.
Among English roads in the latest survey where markings were barely visible were stretches of the M1, M6 and M18. Barely visible marking were also found on stretches of the M9 and M90 in Scotland and on the A465, A487, A4112 and A4143 in Wales.
RSMA national director George Lee said: "These findings are shocking. We could see a clear, direct correlation between deadly roads and deadly road markings when we examined the 10 most dangerous roads identified by the Road Safety Foundation. Now, just a simple cross-section of roads - arguably representative of the entire network - shows a level of deterioration that defies belief."
He went on: "We recognise that the UK is currently under huge financial pressure, but road markings are widely recognised to provide the best, most simple navigation aid to drivers, and to be the most cost-effective road safety measure and it is time we gave drivers the vital clues they need to use our roads."
Road safety minister Mike Penning said: "Simple measures - such as good road markings - can make a massive difference to road safety and I urge highway authorities to consider this carefully as they continue to strive to reduce deaths and injuries on their roads.
"The Highways Agency conducts annual surveys on England's motorways and all-purpose trunk roads, including on the M1, M6 and M18, to assess the condition of road markings. Where deterioration in the level of reflectivity is identified, remedial action is undertaken to ensure that journeys can be made safely and reliably."