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WMATA’s board put off approving a headway policy in July, amid criticism that it set too low a bar. The board will take up the issue this fall. It’s good for Metro to define a specific headway policy, as many other transit systems do, but that policy needs to be clearer so that elected officials, taxpayers and riders know for sure what level of service their money buys.

Today, Metro’s only headway policy is in the annual budget. The budget lays out the normal headway for each train line during rush and mid-day non-rush. The board approves the budget in June, and the staff writes the normal service schedule based on it. For rush periods, the minimum headway is not usually enough for the number of riders, so Metro adds trains and adjusts to meet the demand.

However, the annual budget doesn’t specify the policy for headway before the peak period starts. It doesn’t define when in the day the peak period headway applies. It also doesn’t mandate any headway in the evening and at night. For example, Metro currently schedules trains every 20 minutes at night, but the budget only lists a maximum 15-minute headway.

Also, the headway policy is not part of the draft budget the board circulates to riders for public comment. It’s only after the final budget is published, long after approval, that people can see Metro’s policy.

Metro is trying to fix this by writing down a headway policy for board approval. Like the budget, though, the first version of the policy did not have enough detail. Metro staff proposed a maximum headway of 15 minutes during rush, and 30 minutes otherwise. They said verbally that the policy would apply to service during scheduled track maintenance, but there was nothing in the draft that made this explicit.

Some staff tell me that the suggested 15-minute headway during rush hour could have been anticipating service changes when the Silver Line opens. We don’t really know, and Metro hasn’t specified their plan for Silver Line service. If Metro plans to only provide service every 15 minutes during rush to any part of the system after that, riders and policymakers should have that discussion more openly than as part of a vague maximum headway policy.

What would make a better headway policy?

A good headway policy would have two key elements.

First, it would specifically delineate the minimum headway for regularly scheduled service, for all times of day and all lines. That way, board members and the public will know what level of service we are paying for. The annual budget should incorporate the headway policy, with a draft available by March when the budget comes up for debate.

Second, it would establish a minimum headway policy for planned maintenance. Metro won’t be planning maintenance during peak periods, so a peak headway policy doesn’t make sense here. The policy would be useful in deciding what kind of shutdown to use for track maintenance. If single tracking causes the planned maintenance headway to be too long, it would be better to completely shut down the segment and use shuttle buses.

With these elements in the policy, everyone can have clear expectations, and the General Manager can handle the details of how and when to provide regular service and scheduled maintenance within well-defined parameters.

Michael Perkins blogs about Metro operations and fares, performance parking, and any other government and economics information he finds on the Web. He lives with his wife and two children in Arlington, Virginia.