The British Medical Association in Wales have called for a cut in speed limits along designated walk-to-school routes in Wales.
Doctors say walking to school will make children healthier
It said the move would help tackle childhood obesity by providing exercise and cut road accidents.
It called on local authorities and the Welsh Assembly Government to identify routes and introduce 20mph limits.
The assembly government said the number of children killed or seriously injured on roads had decreased in recent years.
BMA Wales Secretary Dr Richard Lewis said: "If more children are walking to school then they're going to be healthier.
"It addresses the issues of childhood obesity, and again promotes healthy lifestyles, as well as saving lives by reducing injury and death from road accidents."
Dr Lewis said the assembly government, along with other organisations, had already done a great deal of work to help slow down cars near schools.
He highlighted sustainable transport charity Sustran's "safe routes to school" initiative.
The project, which has been running for 10 years, offers free resources to help schools set up travel initiatives to promote walking and cycling over car use.
The BMA wants the assembly government, Sustrans and local authorities to work on a joint strategy to identify all major walk-to-school routes and introduce 20mph zones along them.
The call comes after a motion was passed at the BMA's annual representative meeting in June to call on Parliament to debate the merits of more extensive use of 20mph limits on roads - and covering walk-to-school routes - across the UK.
The assembly government said the number of children killed or seriously injured in 2005 was 53% lower than the average for 1994 - 98.
It said there were safe routes to school initiatives in every local authority in Wales thanks to £27m it had invested since 2000.