Public transit operations began in Milwaukee in 1860. The service consisted of two horse-drawn cars. On June 1, 1975, Milwaukee County took over the bus system and established the Milwaukee County Transit System after taking over the assets of the Milwaukee & Suburban Transport Company, a private operator.

In 2009, Wisconsin Governor Jim Doyle proposed a three-county Regional Transit Authority that would incorporate MCTS.^[6] The proposal faced opposition from some lawmakers and the Regional Transit Authority was never created.^[7]

In late 2013 and into the early part of 2014, MCTS began debuting new technology on board buses. This included introducing real-time bus information allowing passengers to track the exact location of buses, new fareboxes and an electronic fare system by virtue of a smart card (M•CARD), and a stop announcement system complete with visual and audio information. Clever Devices is the provider of the real-time bus information and stop annunciator system, whereas the new fareboxes were provided by Scheidt & Bachmann.^[8]

In 2018, MCTS began a comprehensive study and overview of the entire fixed-route system and began the process of implementing a new system with faster service, more connections, and easier-to-understand routes. Multiple community meetings and forums were held to gather public input on the project. Before the project, only about 40% of the system was high-frequency routes, defined as routes on which buses come every 15 minutes during peak hours. The consensus from the study was that riders wanted faster service and were willing to walk an extra distance to bus stops. MCTS presented two options - transition the system to an 80-20 model, meaning 80% of the routes would be high-frequency, or a 60-40 model with 60% of the routes high-frequency, the latter being what the public ultimately decided. MCTS analyzed every bus stop in the system and removed some lightly used bus stops to speed up service.^[9] The system overhaul was implemented in three phases during 2021, starting on March 7. This first phase included modifications to several routes and introduced two new ones. The second phase, on June 6, 2021, involved changes to the PurpleLine and various numbered routes, plus four new additions. The final phase on August 29, 2021, affected the BlueLine and multiple other routes, added three new ones, and retired two lines. Ridership increased by 14% after the first phase was implemented.^[10]

Due to the COVID-19 pandemic, face masks were required on all MCTS buses. In the early stages of the pandemic, there was a passenger limit of 10 passengers per bus, which was increased to 15, but rescinded on July 1, 2021.^[11] Passengers were encouraged to limit interaction with the bus driver, exit through the back door, and to use contactless fare forms, such as the M•CARD or Ride MCTS app.^[12]

In mid-2023, MCTS transitioned from the M•CARD pass scheme to the WisGo smartcard and Umo mobile app. The M•CARD became invalid on October 1, 2023. A non-expiring stored value system replaced fixed-period passes, and the previous Go Pass and reduced fare programs were merged. Tap-to-pay validators replaced the prior method of presenting codes to transit personnel for mobile app users.^[13]

As of 2026, the system supports digital payments through various credit card and mobile payment methods. WisGo and Umo users receive free time-based transfers. Fare capping is also a core feature, limiting fares to set daily, weekly, and monthly maximums. On-board cash payments remain an option, but do not qualify for transfers or fare capping.^[14]

As part of the overhaul, the previous U-Pass system was replaced by U-Pass WisGo. This separate smartcard provides students in Milwaukee County with unlimited rides through participating universities and colleges. Commuter Value Pass (CVP) users receive a similar employer-issued WisGo card, retaining the same benefits as the original program. Both U-Pass and CVP WisGo holders may also use the Umo app.^[15][16]

Beginning in early 2012, MCTS introduced express bus routes under the brand MetroEXpress. The GreenLine, RedLine, PurpleLine, and BlueLine routes generally feature wider stop spacing and more frequent peak service compared with regular routes.^[17][18]

The East-West Bus Rapid Transit (BRT) line, now known as CONNECT 1, is a 9-mile (14 km) route serving the most heavily traveled corridor in the region. The line runs primarily along Wisconsin Avenue in Milwaukee and Bluemound Road in Wauwatosa. It connects Downtown Milwaukee and Marquette University through the city's west side to the Milwaukee Regional Medical Center.^[19] Project plans were finalized in 2018 and subsequently received federal approval.^[20] MCTS utilized a Small Starts Grant Agreement from the Federal Transit Administration, financing nearly $50 million of the $55 million project total.^[21] It also features battery-electric buses, off-board fare collection, unique signage/bus shelters, with dedicated travel lanes along portions of the route.^[22]

On March 11, 2021, MCTS announced they selected the Nova Bus LFSe+ battery-electric bus for the line, most of which are used for the service. MCTS was the first transit system in the United States to purchase the model.^[23][24] The delivery of first buses were significantly delayed due to supply chain issues, with first being delivered in October 2022. In 2023, the vehicles were temporarily pulled from service due to a battery recall. Nova Bus replaced the parts under warranty, and all were eventually returned to service.^[25][26] CONNECT 1 officially began service on June 4, 2023, operating between Downtown Milwaukee and Wauwatosa. It was the first BRT line in the state of Wisconsin joined a year later by the Metro Transit Rapid A in Madison.^[27][28] The route operated fare-free until April 2024 due to equipment issues.^[29] Two months later, the line was extended to a station within The Couture parking ramp, which is shared with The Hop and other routes.^[30][31] Estimates indicate that the line will average more than 9,500 weekday riders by 2035. These figures represent a 17 percent growth in ridership along the corridor.^{[32][better source needed]}

The freeway flyer routes, including three numbered routes, as well as the Cream Puff Line (Wisconsin State Fair service), the Summerfest Shuttle, and the Brewers Line (game day services to American Family Field), were formally discontinued toward the end of 2022 due to a projected budget shortfall in 2025.^[33] The three "UBUS" routes continued normal operations. In 2023, MCTS operated two Summerfest freeway flyer routes from the College Avenue Park and Ride lot, and the Brown Deer Road East Park and Ride lot.^[34]

MCTS also runs additional services on days when MPS is in session.

Milwaukee County, MCTS, and the Southeastern Wisconsin Regional Planning Commission (SEWRPC) engaged in a study of the 27th Street Corridor. A considerable number of jobs, shopping centers, and medical facilities are along this corridor, currently served by the PurpleLine. This project planned on enhancing transit along 27th Street by re-imagining the PurpleLine as a bus rapid transit line, which would add a second route to the CONNECT system. While the current PurpleLine is already an express route, it does not offer rapid transit service for the majority of the route, as numerous stops are 0.2 miles (1,100 ft; 320 m) apart. This was one of the aspects of transit in this corridor the project would've addressed.^[35] The project also aimed at addressing racial inequalities in the transit system, reduce reckless driving, attract new riders, and overall improve the quality of transit in this corridor.^[36]

However, in late August 2024, Milwaukee County officials recommended and later approved the shelving of the CONNECT 2 project for an indeterminate amount of time due to budgetary concerns. The pausing of the project, according to County Supervisors, will allow MCTS to remain financially solvent until 2028.^{[37] [38]}

In May 2022, Milwaukee County applied for $55.2 million in federal grants to fund 32 battery-electric and 60 clean-diesel buses, though the request was not awarded.^[44] Subsequent funding for fleet replacement included $8.4 million in state grants awarded in March 2023 for 16 battery-electric buses.^[45]

On March 19, 2025, MCTS introduced a new primary livery, replacing the blue, green, and yellow scheme used since 2010. The design uses a light blue, dark blue, and yellow pattern with stylized graphics depicting the Milwaukee Art Museum and the Hoan Bridge.^[43] Later that year, the system secured $8 million through the Congestion Mitigation and Air Quality Improvement (CMAQ) program. This included close to $6 million for 20 clean-diesel buses scheduled for delivery in 2027 and 2028.^[46] An additional $1 million in federal funding for bus replacements was announced in February 2026.^[47]

See: Milwaukee & Suburban Transport Corporation for vehicles delivered pre-MCTS era.

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• Waukesha Metro
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