The dangers of smart motorways are at risk of being overlooked because inquests are failing to record most road deaths as preventable, coroners have been warned.
Research from the charity RoadPeace found that over the last 7 years only one in 40 (2.3 per cent) road deaths were classed as avoidable by coroners.
Only 285 Preventing Future Deaths Reports were issued by coroners for road deaths since 2013, where speed limits, motorway layout and road signs could be changed as a result.
16 coroners’ courts including Buckinghamshire and North East Kent have not issued one in the last 7 years.
During this time at least 12,339 people have died on Britain's roads, including 359 children.
Smart motorways have recently come under scrutiny following the deaths of those stuck on hard shoulders that had been converted into live lanes of traffic.
In October last year, eight-year-old Dev Naran was killed on the M6 after the car he was in stopped on one of these lanes.
Two years previously Jamil Ahmed, 36, broke down on the same hard shoulder of the M6. The lane was not closed because his car was not spotted, after which he was hit and killed by a lorry.
The coroner at the time said they would issue a Preventing Future Deaths report, but due to an “administrative error” did not. One was subsequently filed in November last year.
Following the changes to inquests in 2013, there have been over 5,000 inquests by corroners which were concluded to be Road Traffic Collisions.
Victoria Lebrec, Head of Policy, Campaigns and Communications and RoadPeace told the Telegraph: "If Preventing Future Deaths reports were being used properly, and they were being issued more, it would be a good way of monitoring what initiatives are working or not working.
“There's no way of searching for how many people have died as a result of smart motorways in the last year.
“There's no way of knowing how many PFDs had been issued for a particular stretch of road, unless you were to read through all the reports.
“These are very important if there is an issue with the road such as if the speed is too high or the layout or design is not good.
“These need to be addressed, and Preventing Future Death Reports are the only opportunity really where that then happens.
“One in 40 is really, really low. We would say that every death should have one.
“Coroners need to have these have more training about the other factors which contribute to road deaths and then feel empowered to send these reports to other agencies which aren't necessarily the Transport Authority.”
The Ministry of Justice and the Chief Coroner said that current guidance for coroners was sufficient, and to ask them to issue more preventive measures would damage their independence.
A spokesman for the Chief Coroner said: “It would therefore be inappropriate for the Chief Coroner to direct coroners to issue more reports on a certain topic.”
A Ministry of Justice spokesperson said: “Coroners are independent and it is for them to decide how to conduct their investigations, based on the facts of each case.”