The Metro is designed to provide local, point-to-point service in Paris proper and service into the city from some close suburbs. Stations within Paris are very close together to form a grid structure, ensuring that every point in the city is close to a metro station (less than ), but this makes the service slow , except on Line 14 where the stations are farther apart and the trains travel faster. The low speed virtually precludes feasible service to farther suburbs, which are serviced by the RER.