Halifax Harbour Bridges is wondering if it's time to toss away change and switch to a cashless toll system.

The bridge authority is considering taking out toll booths and gates at the Macdonald and MacKay bridges, and replacing them with a gantry. The gantry would detect MacPasses and take photos of vehicles that don't have them. Those drivers would receive bills in the mail.

"We know that the infrastructure at the toll plazas is getting old," said Alison MacDonald, a spokesperson for Halifax Harbour Bridges.

"The decision that needs to be made is: do we replace the infrastructure as it is with gates and toll plazas or do we do like every other toll facility in North America is doing and that is going cashless?"

MacDonald says the bridge commission is also considering a system with at least one cash lane.

Upgrades are necessary whether they remove the toll booths or not, she said, adding that the switch to gantries won't save money but is considered to be safer.

"You wouldn't have people working in the lanes anymore," she said as an example.

"You have people in their vehicles that might get stuck behind a gate not going up, sometimes they back up in their lane, they get out of their car, so there are safety issues with the current system."

Any decision to remove the cash is still at least a year away.

Even if Halifax Harbour Bridges decides to install gantries, the Nova Scotia Utility and Review Board would have to approve any system that takes photos of licence plates.

MacDonald said 75 per cent of all crossings on across the two bridges already use a MacPass, and at rush hour that increases to 85 per cent.