The design of Auckland's Southern Motorway is in the spotlight, after yesterday's horror crash at Bombay

Three people died and three others were seriously injured in the four-vehicle collision, which witnesses say started when a truck ploughed across a median barrier.

Samoan media report the three dead were seasonal workers heading to Auckland to fly home.

Local Councillor Andy Baker says safety could be improved more.

Baker says something like a gravel pit could slow down vehicles that veer off the road.