On the eve of the annual Bike to Work Day that is forecast to draw thousands of commuters onto two wheels Friday, new research shows that the number of daily bike commuters in the District has increased sharply.

The number of everyday bike commuters in D.C. has nearly doubled since 2007, reaching 3.5 percent of commuters, the National Capital Region Transportation Planning Board said this week. In the counties surrounding D.C., the number of people who ride bikes to work remained fairly steady, a fraction of 1 percent everywhere but in Arlington.

The increase in D.C. bike commuting is evident to the eye as the bright red Capital Bikeshare bicycles seem ubiquitous and thousands of other rides take advantage of the growing network of bike lanes created by the city.

Regional bike and commuter organizations that coordinate the annual Bike to Work Day said a record 12,000 people have registered to participate in this year’s event.

“The Washington D.C. Bike to Work Day grows every year, and this year is no exception,” said Nicholas Ramfos, director of Commuter Connections.

The organizers provide stops along heavily traveled routes where riders can collect refreshments, enjoy performances by entertainers and meet elected officials who support the event.