to cover three routes: Capitol Hill station to Mount Si; Mount Baker station to the Issaquah Alps; and a shuttle from North Bend to Mailbox Peak. A fourth route, between Tukwila International Boulevard station, Renton, and Cougar Mountain, was added in 2019. Operating costs The cost per boarding for Metro was $4.10 in 2005, compared to $2.50 among the country's 15 largest transit agencies and $2.97, the national average. Metro's cost per boarding is 38% above the national average. Metro's higher-than-average cost per boarding can be at least partially attributed to its high percentage of commuter routes, which run at peak hours only, and often only in one direction at a time. As of 2011, 100 of Metro's 223 routes are peak-only. These routes require significant deadheading (particularly on the one-way routes), as well as a very large part-time labor force, both of which drive up costs. Metro's lowest-cost route overall, route 4 (East Queen Anne to Judkins Park), had a cost per boarding of only $0.46 during peak hours in 2009. By way of contrast, Metro's peak-only route with the lowest cost per boarding was route 206 (Newport Hills to International School), at $2.04. Metro's highest cost route by this measure, route 149 (Renton Transit Center to Black Diamond), had a peak time cost of $34.47 per boarding. Route 149 serves the rural southeastern corner of King County. In 2007 it cost $3.64 per boarding to deliver service in the West (Seattle) subarea, $4.79 in the South subarea and $7.27 in the East subarea of King County. At the end of 2008, the systemwide cost per boarding was $3.70. Fares King County Metro has a flat rate fare structure for all riders. In July 2018, Metro transitioned to a single adult fare of $2.75, eliminating off-peak and zoned fares. ORCA cards can also be used. Until 2018, King County Metro had two fare zones, dividing Seattle and the rest of the county, and also had a peak surcharge. Starting September 2022, 18 or younger ride public transportation for free. The King County Metro fares as of July 1, 2018 are: Fare history One-way fare (Peak, 1 Zone), with year of rate change: 2018: $2.75 (peak fares discontinued) 2015: $2.75 2012: $2.50 2010: $2.25 2009: $2 2008: $1.75 2001: $1.50 1998: $1.25 1993: $1.10 1991: $1 1989: 75¢ 1985: 65¢ 1982: 60¢ (peak fares introduced) 1980: 50¢ 1979: 40¢ 1977: