National Highways has been accused of “perversely penalising” cyclists and pedestrians after it was revealed that a number of shared-use paths have been closed due to heavy pollution on adjacent roads.

According to a report on road.cc contributor Laura Laker’s Potholes and Pavements Substack, a shared cycling and walking path beside the A3 in Guildford was closed earlier this summer, with new signs installed prohibiting people riding bikes or on foot, along with diversion signs.

“Hostile” paving, which amount to bumpy stones, was also introduced on the narrow pavement, which runs alongside a 50mph dual carriageway, with cyclists now forced to use the road or undertake a lengthy detour.

According to Laker’s report, the 1.4-mile-long path was closed by National Highways because air quality levels on the A3 exceeded legal annual thresholds, and because the path was within 15 metres of the offending dual carriageway, its users were being exposed to dangerously high levels of pollution.

By closing the path, and stopping cyclists and pedestrians from riding or walking beside the road, the A3 is now, ironically, compliant with the existing regulations. National Highways says the shared path will stay closed until the levels of pollution drop below the legal annual limit for nitrogen dioxide (40µg/m3 NO2), which they predict will happen between 2030 and 2035.

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Local cyclist Steve Cromwell told Laker that the entrances to the path – which he nonetheless described as “not pleasant, nor is it well used as it doesn’t really connect to much” – are now marked by plastic wands, though it appears that cyclists and pedestrians are continuing to use the path, with wheel marks visible in the sand poured over the new stones, according to a photo taken by Cromwell and published by Laker.

Cromwell pointed out that a new kerb drop was installed on a traffic-free section of the diversion put in place from the A3, which he says has made the path easier to use. However, on 17 July, a 19-year-old was killed by a hit-and-run driver while walking along the A3 at night, on a section where the path was closed.

This is not the first time National Highways has closed a cycle path in a bid to limit exposure to overly high pollution levels. In February 2025, the government-owned agency moved a ‘cycle collection point’, where cyclists are picked up by a bus to cross the Dartford tunnel at junction 31 of the M25, and shut the safe cycle path leading to it.

National Highways said at the time that the road will not comply with legal NO2 limits until 2030. Cyclist Terence Hughes told Laker that the new collection point on London Road, West Thurrock, forces people on bikes to navigate a series of busy roads “which can only be accessed by more busy roads”.

London Road, Thurrock
London Road, Thurrock (Image Credit: Google Maps StreetView)

“And when I say busy, I mean loads of HGV traffic,” he said. “The path to the old crossing point connected directly with NCN13 and provided a safe, off-road route. The new crossing point and the ‘alternative routes’ that they mention are on busy roads and I cannot imagine any but the most risk-tolerant cyclist using them.

“So we’ve traded a short section beside a very polluted road for longer sections on still polluted roads but with much more road danger.”

According to emails seen by Laker, during the National Highways’ air quality audit, proposals to introduce barriers, clean air zones, and tunnels were dismissed, with the path’s closure the only option considered viable.

“An alternative, new cycle route was not considered as part of this project,” Connect Plus, the contractor that manages the M25 and the Dartford-Thurrock River Crossing, said in an email.

“As stated previously, there are a number of alternative routes available to cyclists who had previously accessed the collection point, one specific route has not been recommended for use.”

Diversion signage for cyclists, funded by National Highways, was finally installed by the local council in June 2026, around 15 months after Hughes first contacted the agency with his concerns.

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Asked about both the A3 in Guildford and the A282 in Thurrock by Laker, National Highways said in a statement: “The path beside the A282 was a permissive path owned by National Highways, this means there is no automatic right of use.”

It continued: “National Highways has a legal duty to consider measures where annual average nitrogen dioxide (NO₂) concentrations exceed the legal limit. Any changes have been limited to specific sections where pollutant concentrations exceed legal thresholds and where reducing public exposure was considered necessary.

“We recognise that changes to walking and cycling routes can affect local communities and have sought to minimise impacts wherever possible. At both the A3 in Guildford and A282 in Thurrock, a range of potential interventions were assessed before a preferred solution was identified.”

However, Transport Action Network’s director Chris Todd said: “It’s perverse that people who want to walk and cycle are penalised because the motor traffic is too polluting.

“We shouldn’t forget that these are legal limits (air pollution) that should have been met 16 years ago. That’s a failure of central government primarily but National Highways is not without blame.

“As all people using these roads are still being exposed to illegal levels of pollution, why is it that only people walking and cycling are prevented from using the road?”

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National Highways recently told the Transport Select Committee it “works with partners, mayoral strategic authorities, and local authorities to ensure that our network does not act as a barrier to active travel and that it connects and integrates with other networks.

“We see active travel as a core part of how the [Strategic Road Network] SRN can serve and support communities.”

Earlier this year, a report by Breathe Cities named London among 19 global cities, across nine countries, which have slashed levels of two airway-aggravating pollutants by more than 20 per cent in the last 15 years, a “remarkable reduction” in air pollution driven by policy interventions such as cycling infrastructure, the increased use of electric vehicles, and the implementation of London’s Ultra Low Emission Zone (ULEZ), restricting the use of high-polluting cars, the group said.

According to the report, Breathe Cities’ findings demonstrated that large-scale reductions in air pllution can be achieved by promoting active travel, the group acknowledging that “most leading cities have taken major steps to reshape urban space in favour of clean mobility” by expanding cycling networks and pedestrianised zones, while “reallocating road space away from private vehicles”.