Operator says traffic increased more than a third in March-June quarter.
The express lanes' Web site has added a good old-fashioned printable map to satisfy some travelers. Meanwhile, traffic increased during the year's first quarter.
Wording the signs for Virginia's high-occupancy toll lanes is complicated by legal and practical concerns.
All drivers can use the lanes for free from 12:01 a.m. this Saturday through 11:59 p.m. Sunday. No E-ZPass will be required.
On workdays, the new lanes in Virginia averaged 23,308 users, with almost 93 percent of them paying tolls, the report said.
Transurban officials urge drivers to prepare for fall opening as well.