The Portsmouth-based vehicles have been custom-designed by Volvo Special Vehicles, and replace the old fleet of V40s.
The ambulance service expects the cars to cover 60,000 miles a year.
The purchase follows a seven-month trial.
Garry Allen, head of fleet and engineering for the service, said: ‘From a legal perspective we need to ensure our vehicles are fit-for-purpose and that we protect ourselves from the new legislation relating to corporate responsibility.
‘More importantly, for our own peace of mind we need to ensure that hard-working staff, often tasked with risking their lives in the name of others, are supplied with the best possible equipment on the market.’