BAR HARBOR — Acadia National Park visitors will be allowed to ride motorized electric bikes on carriage paths beginning this weekend.

Park officials announced Thursday that Acadia will abide by an Interior Department directive to treat e-bikes like regular bicycles. But the park is limiting trail access to pedal-assisted e-bikes with a top speed of 20 mph.

Supporters say e-bikes are great for older riders who might not otherwise be able to ride.

But critics say they’re too fast and could startle horses. They also say the Rockefellers, who donated the carriage roads, didn’t want motorized vehicles on them.

The new rules apply to 45 miles of carriage paths managed by the park but not 12 miles of paths on private land.