To many local travelers, commuting is a zero-sum game. If somebody else is winning, they must be losing.

M Street bike lane Some drivers find new bike lanes threatening to their space, but they don’t like it when cyclists fail to use them. (Robert Thomson/Washington Post)

Very recently, some of the D.C. area’s travelers have been attempting to calculate the personal additions and subtractions involved in sharing the roads and sidewalks.

I can’t spot anything really new in this dust-up among car drivers, bicyclists and pedestrians. I’m familiar with all the challenges that each category of traveler hurls at the others. What bothers me is the categories.

They bother me because improvements in the convenience and safety of getting around everyday are more likely to occur when governments need to respond to a constituency of travelers. And the D.C. region lacks a broad constituency of travelers to apply pressure for those improvements.

By contrast, parents and teachers form powerful and long-lasting communities of interest to press for more resources.

There’s no broad constituency of travelers. There are drivers, cyclists, pedestrians and transit users all pressing for particular improvements, sometimes successfully, but often not so successfully. They may be represented by groups that can lobby officials long-term. Or they may come together temporarily to advocate for some particular project or program. But the constituencies are often narrow, and often focused on blocking something they think is bad rather than creating something they think is good.

There’s not enough alliance among travelers to upgrade traffic and transit services and too much traveler versus traveler to block changes that might benefit everyone. We see bus riders vs. drivers in the debate over whether to create bus lanes on 16th Street NW in the District. It was bike riders vs. drivers in the debate over creating a bike lane on King Street in Alexandria. It was drivers vs. cyclists and walkers in the debate over safety improvements along the George Washington Parkway.

With the Silver Line about to open, we don’t see Metro riders banding together to protect their interests. We see Blue Line riders vs. Orange Line riders vs. these new people coming down the Silver Line.

Somehow, our ability to form alliances on education or health care or environmental protections breaks down when we talk about improving the transportation system. To many people, there is no transportation “system.” There’s a line from Point A to Point B — the line each of us travels every day. We share the line only grudgingly, and sometimes angrily.

Here’s a reading list of writers who have participated in the recent debate about us vs. them.