The national unit will patrol motorways and major roads from 10 bases across Scotland. There are currently about 600 road patrol constables and that number is expected to stay the same, but a third of them will make up the trunk roads team.
Mr House said: "By creating a new national roads policing unit with bases across the country, we can raise our visibility with the public across some of our busiest roads, encouraging responsible driver behaviour and tackling those who make the roads less safe for others.
"We have looked at how roads policing is resourced across Scotland and we are changing that a little bit to focus effectively on where we see casualty hotspots to make sure we are putting the resources where they need to be.
"Roads safety and roads policing is one of the biggest concerns the public have and they're quite right to because there were 176 fatalities last year on Scotland's roads, which is a lot higher figure than the homicide figure."
Mr House said the move would reinforce local policing, with divisional commanders having their own traffic unit which could be deployed quicker.