Ontario has installed HOV lanes on a major highway that has a new design and different set of rules that can be confusing for some motorists seeing them for the first time.

The Department of Transportation said the newly installed HOV lanes on Highway 400 in Vaughan opened this week.

This is how they work.

Existing HOV lanes in Ontario allow vehicles to enter or exit by moving over a dotted track marker located along the HOV lane.

The driver merges out of the HOV lane and right back into the normal traffic flow.

The new design of the Highway 400 uses a dedicated transfer lane for motorists to get in and out of the HOV lane.

Motorists wishing to leave the HOV lane must merge into the transfer lane before returning to the regular traffic lanes.

Why is the government doing this?

The Department of Transportation told CTV News Toronto that the existing HOV lanes provide “satisfactory guidance” to drivers getting in and out of most traffic conditions.

But in some situations, the government says there may be operational and safety concerns when HOV rail traffic merges back into the typically slower regular traffic in general.

The newly designed lanes give motorists a chance to slow down in normal traffic before reuniting.

Highway 400 is currently the only place where these lanes exist and no changes have been made to Highway 404, Highway 403, Highway 427, Highway 410, Highway 417 and QEW.