The city's most popular car sharing service is shrinking its coverage area, leaving customers in the outskirts of the city without a ride.

The Car2Go service area will shrink to 73 square kilometres from 114 effective Sept. 28, the company said.

The smaller service area covers the parts of the city where 96 per cent of Car2Go trips are taken and 92 per cent of its members live — effectively cutting service to 8 per cent of its customers.

The company says the move is designed to address shortages in the downtown core — a constant complaint from customers since the service began in 2012.

"The sheer size of Calgary's Home Area does not allow members to easily access a Car2Go vehicle, as it requires our vehicles to be spread out too thin in low demand areas where they are idle 5.5 times as long," the company said.

"We believe that this change will help ensure that our vehicles are in constant circulation, and only occupying fixed space for a limited amount of time," it added.

The Texas-based company said it would leave the door open to returning to these areas as the city continues to grow.

It is also exploring the possibility of adding designated parking spaces outside the newly-shrunken service area, it said.