With the Washington region’s population boom, more people have had to figure out how to commute in an area where the roads are infamously congested and the Metrorail system has a limited reach.

For an increasing number of commuters, the answer has been the buses crisscrossing the region’s suburbs, where city- and county-run bus systems have seen a steady rise in ridership in recent years.

But relying on buses means depending on lines that in some cases have to traverse big areas and are at the mercy of the region’s traffic.

As a result, buses operated by many of the suburban jurisdictions can be late more often than commuters would want, not unlike the buses operated by Metro.

“The morning seems really reliable, which makes sense for a bus system,” said Meaghan O’Malley, 33, of Fairfax, who started taking the Fairfax Connector last year. “They start out great, but things slow down throughout the day with breakdowns and traffic.”

Even as ridership has risen, road capacity hasn’t. But with buses seen as a way to reduce congestion by taking drivers off the road, some jurisdictions are constructing or considering new lanes meant to enhance bus service.

A five-mile stretch of bus-only lanes in Arlington County and Alexandria is scheduled to open next year. In Montgomery County, a task force has recommended a 160-mile system of express bus lanes, though a recent study said this plan is not practical.

The bus lines operated by each of the region’s suburban jurisdictions are often overshadowed by Metro’s vast system of rail and bus lines, but they are workhorses and a vital link for many commuters.

The lines in Montgomery, Prince George’s, Fairfax, Arlington, Prince William and Loudoun counties and the city of Alexandria logged more than 52 million trips last year, up from more than 49 million in 2010.

“It’s definitely decreased stress tremendously,” O’Malley said of commuting by bus. “I don’t like driving. The traffic’s horrible. . . . I personally enjoy it for my work commute.”

Only Montgomery County’s Ride On service, the suburban system with the highest ridership, logged fewer passengers in 2012 than in 2010. Ridership on Metrobus has been growing, too, to 129.9 million in 2012 from 120.2 million in 2010. Meanwhile, Metrorail’s ridership dropped to 212.1 million from 217.3 million during the same period.

Agencies have tweaked and boosted service to accommodate the growing bus ridership and to draw additional riders. OmniRide in Prince William County and Fairfax Connector began running buses in the Capital Beltway express lanes as a way to offer faster trips.

Arlington Transit increased service on some routes, including adding buses to its popular ART 41 route, which runs between the Columbia Pike and Court House areas and is responsible for about 40 percent of Arlington Transit’s ridership. OmniRide beefed up service on several routes, including a route that runs alongside Interstate 66 to and from the West Falls Church Metro station. TheBus in Prince George’s County added trips to several routes, including the one between the Greenbelt and New Carrollton Metro stations.

Traveling by bus is often cheaper than traveling by train or car, and that is often the appeal for many commuters. But for all the value in commuting, riders from across the region say that outside of the weekday rush-hour windows, lags in service can be a problem.

“The buses go to a lot of places, but during the middle of the day they only go once an hour, so you wind up waiting outside for a long time,” O’Malley said.

Kayann Dobson, who takes a Ride On bus from Silver Spring to Friendship Heights to get to her job as a cashier, said “the buses are not reliable” during these off-peak hours.

The problem is even more acute on the weekends, riders say.

“On the weekends, the buses just don’t run frequently enough to get around,” said Matt Miller, 33, of Reston. “It works really well during the week, but on the weekends it’s just not great.”

About one out of five Ride On buses was late last year, according to the county. That is similar to numbers reported by Arlington Transit and slightly better than those reported by TheBus. Metro reported that about one out of four of its buses was late last year.

Zahra Javaheri, who takes a Ride On bus a few days a week, said she has waited for 45 minutes for a bus before giving up. On occasion, she has taken buses an hour early to make sure she can get somewhere on time.

“They are not on time,” Javaheri said. “But the buses are convenient.”