The University of Minnesota Landscape Arboretum has begun using a pair of solar-charged electric carts to take visitors on free rides around its tree, grass and flower collections.

The 11-passenger vehicles, called "circulators," made their debut over Memorial Day weekend. They are designed with roofs but no doors to allow passengers to easily hop on and off at points along the arboretum's Three-Mile Drive.

The circulators will not replace the arboretum's longer tram, which carries 42 people and offers a 45-minute narrated tour of the grounds but which does not stop along the way.

The 1,137-acre arboretum in Chanhassen receives about 330,000 visitors annually.

Arboretum spokeswoman Barbara DeGroot answered a few questions about the new circulators.

Q: Why are you using them?

A: The rides will encourage people to get out of their cars and into the greenery. They also will reduce private vehicle traffic on Three-Mile Drive, which can get congested on weekends and during the arboretum's busy spring blooming season and its dramatic fall colors.

Q: How much did they cost?

A: $31,000 each. They were funded by donations at the 2012 Arboretum Gala in the Gardens benefit.

Q: When do they operate?

A: Friday through Sunday, between 10 a.m. and 3 p.m.

Q: Are they replacing the traditional tram, with its narrated tour of the grounds?

A: No, the tram will still run its usual schedule four times a day. The tram ride costs $3 and does not stop to let people get on and off during its 45-minute drive.

Q: How are the circulators different?

A: The beauty of the circulators is they will provide free rides with "step on, step off" options at a few pre-assigned stops along Three-Mile Drive. This is especially important with the arboretum opening a new sculpture garden along the drive this summer which is sure to attract more visitors. Along the drive, families can also enjoy our maze garden, the garden for wildlife, shrub rose collection, prairie areas, shade tree collection and other features.

Q: How about accessibility?

A: The circulators are wheelchair-accessible.

The arboretum also plans to build rest stops and provide restrooms at places along the drive where the vehicles make regular stops.