Uber currently operates in four times as many cities worldwide as Lyft and is expanding rapidly. In late April 2014, it celebrated a milestone of serving 100 cities; less than eight months later, it serves about 250. Meanwhile, Lyft co-founder John Zimmer told CNBC that his company is looking to add 100 new cities worldwide in 2015, which could make it more competitive with Uber. Here is a look at the cities where these two businesses have been expanding service recently and the benefits of these services.

Uber's Global Expansion

Uber added seven global cities to its roster in the first half of December. Some new cities represent official launches of full-scale service, while others are in the test phase, called secret Uber. Ride availability is low during testing, but Uber expands to full service if the test phase is successful. Secret Ubers arrived in Medellín, Colombia on December 12 and in Bulgaria's capital Sofia on December 9. (New users in Sofia could get two free trips worth up to 30 BGN each.) In addition, the company began testing UberBLACK, its premium service, in the Bahraini cities of Manama, Muharraq, Seef, and Saar on December 15. In these markets, Uber is offering free rides worth up to SAR 80 through January 31, 2015.

Uber service officially launched in Hanoi, Vietnam on December 4 and in Monterrey, Mexico on December 12. With the official launch in Hanoi, Uber expanded service to nearly a dozen areas in Vietnam, including Tay Ho, Hoan Kiem, and Ba Dinh. In Monterrey, Uber formalized its fares, with a minimum base fare of $70 MXN, the equivalent of about US$5. Uber offered new users there a free ride worth up to $200 MXN.

Uber also began testing in Tianjin, China on December 10. People's Uber, as the service is called there, is a pilot, non-profit ridesharing service that encourages carpooling to help alleviate the city's pollution and traffic-congestion problems. The drivers are volunteers. New users could sign up for 50 yuan in free ride credits. (For related reading, see Winners and Losers in the Sharing Economy.)

Uber and Lyft in Florida

Lyft brought service to Orlando on August 1 and offered all new users two weeks of free rides. Meanwhile, Uber expanded UberX, the company's lowest-priced ride option, to cities across Florida on December 4. It offered new customers there five free rides worth up to $20 each for a week and a half. With Uber available in dozen of cities from Daytona Beach to Fort Myers to Panama City to Key West, the company says more than 82 percent of Floridians can now access its service.

Lyft and Uber at Airports

In September, Nashville International Airport authorized a pick-up zone for ridesharing, making it easier for Lyft and Uber to operate there. In October, San Francisco International Airport decided to formally allow Lyft and Uber to operate at all terminals. In November, Lyft signed a long-term agreement with Denver International Airport to become an authorized ridesharing service providing transportation to and from the airport. UberX got permission to operate at Denver's main terminal in early December, while UberBLACK had already been operating there as a commercial transportation service.

Ridesharing in San Francisco and Los Angeles

Lyft launched Lyft Line in San Francisco in August, in Los Angeles in September, and in New York City in December. This ridesharing service connects people traveling in the same direction with door-to-door service from a Lyft driver at a fixed price that is up to 60 percent less than a regular Lyft ride. Lyft Line could help reduce traffic congestion and automobile pollution while creating another low-cost transportation choice for passengers. And Lyft's new Driver Destination service, introduced at the end of November, lets drivers notify Lyft when they are taking a personal trip, such as running an errand, so they can pick up a fare headed the same direction and make some extra cash.

Similar to Lyft Line, UberPool connects passengers headed in the same direction in San Francisco and New York City. Passengers can pay up to 40 percent less than they would for UberX when using the service in San Francisco and up to 50 percent less in New York City. If no one is available to share a ride, UberPool will still give a 20 percent discount over the UberX rate in San Francisco, but passengers pay the regular UberX rate in New York City while the service is still being tested.

Benefits of Uber and Lyft Expansion

Locals, visitors, and tourists in cities where Uber and Lyft are expanding get the obvious benefits of additional transportation options that are often more convenient, nicer, and less expensive than the status quo. These services can also increase safety and comfort; customers request rides through their smartphone apps and can wait inside until their ride arrives instead of standing on the street to hail a cab. Also, ridesharing services like Lyft Line and UberPool have the potential to reduce overall traffic congestion, while also creating new opportunities for people to meet and form friendships and business relationships.

The expansions also create new job opportunities that can serve as a primary of income, a second job, or a way to offset the costs of vehicle ownership. Drivers for both services are independent contractors, so they have flexible schedules and can even work for both services. Uber's arrival created the opportunity for a full-time, salaried general manager in Sofia, while the new service in Tianjin created the need for a general manager and community manager, both full-time salaried positions located in Beijing. Both companies are hiring for other full-time positions as well. Lyft has dozens of openings for positions such as data analyst, infrastructure engineer, sales force analyst, and marketing analyst. Uber is hiring worldwide for scores of positions ranging from accounting manager to background check researcher to communications director. (For related reading, see Pros and Cons of Uber and Other E-hail Apps.)

The Bottom Line

Uber and Lyft offer customers innovative solutions to longstanding transportation problems and have created thousands of new jobs in the process. It will be interesting to see whether cities become more receptive to letting transportation network companies operate legally, what new competitors pop up, and how Lyft and Uber will continue to expand in 2015 and beyond.

Editor's note: The author of this article has no affiliation with or ownership interest in any of the companies mentioned.