Streetcars are experiencing a renaissance in American cities. After Portland and Seattle led the way in the early 2000s, eight more cities have opened streetcars since 2013, the most recent opening last week in Detroit.

Streetcars, often slow-moving trollies that share lanes with traffic, are more about spurring development in new parts of the city than providing the fastest transportation option. The trend is picking up steam and eight more cities have streetcar lines under construction or planned to break ground by 2020.

1. Oklahoma City

A rendering of the Oklahoma City streetcar, expected to open in 2018

Timeline: Under construction, projected completion late 2018

Under construction, projected completion late 2018 Route Length : 4.6 miles

: 4.6 miles Estimated cost: $131.8M

Oklahoma City residents voted in 2009 to fully fund the $131M streetcar through a citywide one cent sales tax. Construction began in January and is expected to be complete by the end of next year. The main 22-stop loop will run through the central business district, Midtown, Bricktown and Automobile Alley. A shorter 2.3-mile loop will serve just the stops in Bricktown, a former warehouse district that has transformed into an entertainment hub. The streetcars, built by Pennsylvania-based Brookville Equipment Corp., will share lanes with cars and be powered by overhead wires.

2. Milwaukee

A rendering of the Milwaukee Streetcar, which began construction in 2017

Timeline: Under construction, projected completion in 2018

Under construction, projected completion in 2018 Route Length : 2.5 miles

2.5 miles Estimated Cost: $128M

Construction on Milwaukee's streetcar began in April, and will be built in two phases. The first two miles are expected to be completed in summer 2018, with an additional half mile lakefront line opening in 2019. Half of the project's funding came from the federal government, with the rest coming from local tax increment financing districts. The streetcar will be powered by overhead wires and most of the route will share the lane with cars while a short stretch downtown will have dedicated lanes.

3. Fort Lauderdale

A rendering of the Wave Streetcar in Fort Lauderdale

Timeline: Construction to start in 2018, projected completion in 2020

Construction to start in 2018, projected completion in 2020 Route Length : 2.8 miles

2.8 miles Cost: $195M

The Fort Lauderdale streetcar, dubbed The Wave, has been in planning for more than a decade. When the project was awarded federal funding in 2012, covering roughly 42% of its costs, residents were told it would be completed by 2016. But local funding issues and design changes continue to push it back. The streetcar will share lanes with cars and be powered by overhead wires.

4. Tempe

One of three design options for the Tempe Streetcar

Timeline: Construction to start summer 2017, projected completion in 2020

Construction to start summer 2017, projected completion in 2020 Route Length : 3 miles

3 miles Estimated Cost: $186M

Tempe's streetcar received $50M in federal funding in the FY2017 budget, and construction is expected to begin June 1. The line will have 14 stops, four of which will serve Arizona State University. Tempe's streetcars will be battery powered, allowing them to operate without overhead wires.

5. Orange County

A rendering of the Orange County streetcar

Timeline: Construction to start in 2018, projected completion in 2020

Construction to start in 2018, projected completion in 2020 Route Length : 4.2 miles

4.2 miles Estimated Cost: $298M

California Gov. Jerry Brown dubbed the Orange County Streetcar a top infrastructure priority in February, which could help expedite a federal permit it needs to complete a bridge over the Santa Ana River. The 4.2-mile line will have six cars running between its 10 stations and will stop every 10 minutes during peak business hours.

6. Sacramento

A rendering of the planned Downtown/Riverfront Streetcar in Sacramento

Timeline: Construction to begin summer 2018, completed by 2021

Construction to begin summer 2018, completed by 2021 Route Length: 4 miles

4 miles Estimated Cost: $200M

Congress included $50M for the Sacramento streetcar in its FY2017 budget. More funding still needs to be raised for the project, which is still in the planning and design phase, but state officials expect it could start construction by June 2018 and be completed by June 2021. The route would have 21 stops, crossing the river from West Sacramento through downtown and passing by the state Capitol and the Convention Center Complex.

7. New York City

A rendering of New York City's planned Brooklyn Queens Connector streetcar

Timeline: Construction to start in 2019, projected completion in 2024

Construction to start in 2019, projected completion in 2024 Route Length: 14 miles

14 miles Estimated Cost: $2.5B

Mayor Bill de Blasio has been pushing a massive streetcar line that would connect Brooklyn and Queens. Several major developments would benefit from the line, which would run from Astoria to Sunset Park and fill a major gap in the subway system's service. The line would run 24 hours a day at five-minute intervals, primarily in dedicated lanes. It would cost riders the same as the subway and be integrated with MTA fare payment.

8. Washington DC Extension

The DC Streetcar currently runs on H Street NE

Timeline: Construction could begin in 2020

Construction could begin in 2020 Route Length: 1.8 miles

1.8 miles Estimated Cost: $173M

The initial 2.2-mile DC Streetcar opened in February 2016, running along the bustling H Street corridor from Union Station to Oklahoma Avenue NE. Mayor Muriel Bowser has plans for the project to run westward through downtown to Georgetown, but the next addition will extend the line east across the Anacostia River to the Benning Road Metro station. The eastern extension still has to complete its environmental review and design process, but Bowser included funding for the project in her recent budget proposal. DDOT chief project delivery officer Sam Zimbabwe said it could break ground as soon as 2020, with construction lasting 24 to 36 months.