Buses at WMATA’s old Ballston bus yards, which has since been closed and redeveloped.

Here’s a simple fact of bus planning: You can only run as many buses during the day as you can park at night. Want to expand service but your bus parking lot is at capacity? Then sorry, too bad, can’t do it.

This simple issue drives bus operations as much as just about any other planning issue. Not only do you need big parking lots with maintenance garages attached, but they need to be geographically close to the bus routes they serve, because otherwise it costs too much to drive empty buses and drivers changing shifts back and forth from the parking depot to their routes.

In the transit supportive core of the Washington region, where bus ridership is booming and land is getting more and more expensive, the availability of bus parking is very probably the largest constraint on expansion of bus services. Multiple WMATA bus yards have been closed in recent years, claimed by high-density redevelopment near the baseball stadium and in Ballston.

So it’s a pretty big deal that last week WMATA opened a new bus storage yard, its first since 1989. The new Shepherd Parkway Metrobus Division is in Southwest DC and will house up to 250 buses, most of which will serve routes in SW and SE DC.

In the long term, improvements like this are the necessary ground work for the more interesting things that can happen later as a result, such as new bus routes, improved frequencies, and more high-capacity articulated buses. Good work, WMATA.