Express Drive, General Motors’ short-term car rental program for Lyft drivers, has expanded to Boston, Washington, D.C., and Baltimore.

After investing in the ride-sharing app Lyft, General Motors launched Express Drive, a short-term car rental program aimed at attracting more drivers to the Lyft service. The service initially started in Chicago in March and now has expanded to include Boston, Washington, D.C., and Baltimore.

Since launching in March, 30% of new Lyft driver applicants in Chicago request an Express Drive vehicle, according to a Lyft report. And nearly 1 million miles have been driven in Express Drive vehicles.

Initially, the Express Drive program offered Chevrolet Equinox SUVs to Lyft drivers in Chicago, but the program will be expanding the types of vehicles available, according to Lyft.

The cars will be rented out for $99 a week, but if a driver completes 65 rides or more in a week, the rental is free. Drivers will pay 20 cents a mile, but this charge will be dropped once they surpass 40 rides per week.

Click here for the full Lyft report.