Article updated on July 5th.

Third Avenue slices through the heart of downtown Seattle and passes landmarks like Benaroya Hall, a world-class symphony performance space, and The Arctic Building, once home to an explorers’ club for successful returnees from the Klondike Gold Rush. At rush hour, you won’t get a chance to admire the former’s curved glass façade or the latter’s terracotta walrus sculptures from a car window, but you can on a bus- the most popular form of public transport in the city. Third Avenue becomes a four-lane transit mall with both directions for only buses during morning and evening rush, with up to 220 buses per hour passing through at peak times.

The scene on 3rd Avenue is indicative of Seattle’s transit story, where buses are the workhorse of a booming metropolitan area as it prepares to invest in higher-capacity modes. In 2012-2013, it was the fastest growing city in the U.S., a demographic trend driven by technology companies like Amazon, whose campus is adjacent to downtown. The city has come a long way from the declining 1970s, when a billboard read, “Will the last person leaving Seattle – Turn out the lights.”

But whereas the other major West Coast cities – Vancouver, Portland, San Francisco, and Los Angeles – have built light or heavy rail systems, Seattle has been the odd one out. In 1968 and again in 1970, voters rejected a 90/10 federal match for a rail system similar to Bay Area Rapid Transit. The failed initiative, known as Forward Thrust, sent the $900 million in federal dollars to Atlanta, where it became the MARTA system.

That made Seattle one of the largest all-bus transit systems in the country, until 2007 when the South Lake Union streetcar opened and 2009 when the Sound Transit light rail began. Even still, buses continue to serve as the backbone for the region’s transit, which make Seattle’s rank in the top 10 U.S. metros for transit trips per capita per year all the more impressive. In fact, between 2010 and 2014, Seattle saw the biggest jump in bus ridership of any major US city due to their investments in service improvements.

Seattle is leading the way in rethinking how to provide bus service. With calls for service being the new infrastructure, frequency is freedom, and access is everything, Seattle is making great strides in making buses easier and better to use.

“All the other cities ahead of us have big, mature rail systems,” says Seattle Department of Transportation director Scott Kubly, whose agency has benefitted from the Move Seattle property tax levy that voters approved last year. “In terms of a city that has predominantly a bus-based transit system, we’re far ahead of everybody else.”

Seattle’s buses benefit from investments in right of way with significant mileage of bus-only lanes, a large volume of queue jumps, and a fleet of all-electric buses and electric trolleybuses. They are adding different types of service, like Rapid Ride, better signage, and real time information kiosks. While the Sound Transit referendums – a third, $54-billion measure will be on the November ballot – mostly get credit for authorizing light rail construction, they have all contained funds earmarked for improvements to bus service.

“We’ve made huge investments throughout the region to provide faster, more reliable services through several hundred million in new transit centers and new HOV express ramps [buses and 2- or 3-person vehicles share these lanes],” explains Sound Transit information officer Bruce Gray. “We’ve been able to build up our ridership as we’re planning and building up our rail system.”

Indeed, in the same period of time as Seattle hit record growth rates – its highest population surge since the Klondike Gold Rush – it also saw the U.S.’s biggest bump in bus ridership. Forty-two percent of the 44,000 new workers who streamed into Seattle from 2010 to 2014 commute by bus, which means that one in five Seattleites – 78,000 people – take the bus to work.

While Sound Transit operates the country’s largest fleet of commuter buses that run between urban centers – both to/from Seattle as well as other job hubs like Tacoma, Bellevue, and Redmond, home to Microsoft – most of the buses in and around Seattle are operated by King County Metro. (Seattle and many of its outlying suburbs are part of King County.)

This year, King County Metro prepared Metro Connects, its first long range plan in over 20 years. The plan has aggressive targets to double ridership, boost connections between bus and light rail, and triple the percentage of people living within 10 minutes of frequent bus service, such as the Rapid Ride lines, which currently carry 62,000 daily riders.

“During the past year we’ve seen record investments in transit through Seattle voter funding and King County funding through better revenues and budget savings,” says King County Metro spokesman Jeff Switzer. Last year saw record ridership on the system of nearly 122 million passengers.

Voters did finally approve rail in 1996 and 2008 when they agreed to the Sound Transit I and II ballot initiatives, which has thus far built 20 miles on light rail, known as Link, with another 20 miles under construction. In March, the long-awaited Link extension opened from downtown to Capitol Hill, the city’s densest residential neighborhood, and the University of Washington, the state’s largest employer. The number of Northeast Seattle residents with access to transit every 15 minutes or less jumped from 8,700 to 28,000 after the adjustments. While Link will be a welcome addition to the transit system, it will take decades to build out to the region. In the interim, buses will continue to be the vital foundation for sustainable transportation that increases access and gives the people of Seattle freedom to travel without a car.