John Shepherd was left traumatised when his wife, Brenda, and two children, Richard and Lynne, were struck by a car outside Harmans Water Primary School in 1986.
But despite the tragedy, there is still no 20mph speed restriction outside the school in Wellington Drive.
Less than half of the borough's primary schools - 13 out of 27 - have a 20mph limit enforced outside their gates and no Bracknell Forest secondary schools have such a restriction.
Mr Shepherd's children - who were 11 and seven-years-old at the time - were unharmed but spent years shell-shocked, so much so that Mr Shepherd had to give up his job to look after them.
"It totally changed my life and the children were utterly traumatised," he said. "If that car had been going at 20mph my wife would almost certainly be alive today.
Mr Shepherd, a retired entrepreneur, argued that if it is not possible for a 20mph speed limit to be in place all the time that perhaps it could be in force for certain hours of the day.
Bracknell's MP Dr Phillip Lee has backed Mr Shepherd's campaign and said: "I am particularly struck that only 13 out of 27 schools in the borough have 20mph speed limits, and would certainly support a reduction around the other 14.
"Reducing speeds will reduce casualties, with research showing that for each one mph reduction, casualties drop by 5%.
"With support from Government, Bracknell Forest Council and our local community, I think we can achieve this and save lives."
However Cllr Mary Ballin, Bracknell Forest Council's executive member for transport, argued that some roads are simply "not suitable" for a 20mph limit due to their structure.
She added: "Where it's possible, the speed limits outside schools are in place."
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