Washington » At first glance, everything seems out of place on the map of a new interstate road system taking shape across the nation.

Interstate 95 runs down the stunning sweep of the Pacific Coast, not the congested blandness of the Eastern Seaboard. Route 1 meanders along country roads, not strip malls. And you'll get your kicks on Route 76.

Mapmakers gone wild? Not quite.

State officials and bicycle enthusiasts are stitching together more than 50,000 miles of pedal-friendly pavement to form a vast network of bicycle routes connecting byways, cities and offroad trails in a system like the one created for cars and trucks over half a century ago.

The American Association of State Highway and Transportation Officials, working with the Adventure Cycling Association and other groups, recently approved a plan, four years in the making, that lays the foundation for the network. Now it's up to each state to create the routes and put up signs.

"It's a big turning point," said Jim Sayer, executive director of the Adventure Cycling group, the authority on transcontinental bike travel.

"We're coming down out of the clouds, having created the overall national plan, and getting to the nitty-gritty of creating interstate routes on the ground. It's a great opportunity for the U.S. to establish what could be the largest bicycle route network in the world."

The effort relies on cartography instead of construction, signposts instead of earth-movers.

Working from a bewildering tangle of existing roads, planners mapped a web of corridors where the national bicycle system should go. They considered traffic volume, terrain, amenities and ways to link together lightly traveled byways, secondary roads, urban trails and already established transcontinental bicycle routes.

Each corridor on the map they approved is a broad swath 50 miles wide; the precise routes within each corridor are still to be designated, numbered and given signs.

To avoid confusion, the proposed numbering system is reversed from interstate highways. For example, Route 10 is the southernmost east-west interstate for motor vehicles; bicycle Route 10 runs east-west close to the Canadian border.

For more information on the plan, visit www.adventurecycling.org/routes/nbrn/usbikewaysystem.cfm.