'Pollution tunnels' could be used on motorways in England to cut levels of dangerous pollutants near residential areas.
Highways England said that it had previously performed tests on such a system on the M62 near Manchester in 2015, using a nitrogen dioxide absorbent polymer to soak up toxic gases.
The chemical compound is one of the leading causes of lung disease and in a release yesterday Highways England said it was looking into whether the system was cost-effective enough to go nationwide.
The agency did admit though, that the benefits of the system on air quality were "still to be fully understood" following the experiment two years ago.
It said: "The results from the monitoring of such trials will help us understand if this has been a success with the potential to implement barriers on our network. We are also investigating if we can reduce the costs to construct a canopy, which is a tunnel-like structure designed to prevent vehicle emissions reaching our neighbours."
A spokesperson admitted: "The best solution to accommodating the extra traffic on our roads, without negatively impacting on air quality, is cleaner low-emission vehicles. In the meantime, we are investing £100 million to test new ideas including less-polluting fuels and road barriers which can absorb harmful emissions."
The document also said Highways England will be installing electric charging points around the country "to ensure that 95% of our network will have a charging point every 20 miles."