New rules putting tighter speed limits on ambulances take effect on Friday, but Alberta Health Services insists the change will not negatively impact patient response times.

Currently, EMS vehicles can travel 25 per cent faster than the speed limit when responding to emergencies and transporting patients.

As of Friday, they will be limited to 15 km/h over the posted speed limit.

"We want to be very clear; changes to ambulance driving speeds are being made solely with the safety of patients, staff and the public in mind and will not put patients at risk," AHS said in a statement.

"When an ambulance is transporting a patient to hospital, a paramedic is in the back of the ambulance, with the patient, providing care. Travelling at high speeds in these situations increases the risk of collision that could be catastrophic to the patient, to staff and to members of the public."

Amanda Rayner, with the Alberta Paramedic Association, agrees that faster isn't always better.

"It's actually documented that speed does not usually come into play with a more positive patient outcome. There are so very, very few cases where getting there faster or getting them to the hospital faster would have actually prevented a certain outcome in the patient to have occurred," she said.

Rayner says ambulances are large and hard to manoeuvre — and accidents can happen.

"It's helping to mitigate the amount of potential civil and criminal liability against our paramedic professionals as they're driving the ambulance."

The union representing paramedics and AHS declined CBC's requests for an interview.