A coroner has warned of the dangers of smart motorways after an eight-year-old boy was killed on the M6.
Dev Naran was in his grandfather's Toyota, which had pulled up on the hard shoulder, but the lane was being used and the car was struck by a lorry.
The boy died in the crash, between junctions five and six, in May 2018.
Coroner Emma Brown said she had written to Highways England which told her smart motorways were "significantly safer" than standard ones.
She wrote to the agency following the inquest into the death of the boy, from Leicester, which concluded on 11 October.
The lorry was travelling at 56mph (90km/h) when it hit the rear of the Toyota near Birmingham, Ms Brown said in her report.
Due to the geography of the stretch of road, she added the lorry driver "only had a very short time" to react.
Hundreds of miles of motorways in England have been made "smart", which means the hard shoulder may be used as a running lane.
In her report, Ms Brown said it was not known why Dev's grandfather had stopped on the hard shoulder which at the time was "clearly marked" as a running lane.
When a hard shoulder is in use as a lane, a speed limit is displayed above it. A red cross is used if it is closed.
Ms Brown said drivers "may become confused" despite signage. She also said Highways England had no system for automatic alerts to a stopped vehicle in a lane.
Although a radar system is being developed, it is not being considered for hard shoulder lanes.
Highways England said its "deepest sympathies" were with Dev's family but added it "cannot urge drivers strongly enough to only stop on the motorway in an emergency".
Dev's family has previously described him as "a kind and compassionate angel" who "excelled at school and wanted to become a doctor".
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