By most measures, the Hubway bike-share program has had a very successful fifth year. It celebrated its 5 millionth ride and expanded deep into East Boston, South Boston, Dorchester, and Roxbury.

But Hubway’s growth has also meant a surge in what is the bane of any user of the large black-and-silver bikes, or their friends who are waiting for them: trips that can’t ever start because a station is empty or, even worse, arriving to a destination to find all the docks full.

If users think it happens a lot, they’re right. In October alone, Hubway’s 185 stations had a staggering 14,887 instances of full or empty stations, compared to 11,863 in the same month last year, according to the data made available on hubwaytracker.com.

In a city full of clogged traffic and delayed public transit, a bike ride should be the most predictable commute next to walking. I asked some Hubway users, and Boston attorney Adam Kessel says he’d use the service “about 50 percent more” if he knew that he could rely on it between his Seaport office and connection at South Station—exactly the kind of trip that is faster on two wheels than on the crowded Silver Line.

“Being able to use it allows me to stay at work a few more minutes, so if I can’t count on it being there I have to leave work earlier,” Kessel says. “Since it started the Hubway’s usage has exploded but the supply hasn’t kept up with the number of people who want to use it.”

None of which is news to Hubway. “I would list it as one of our major challenges,” says Emily Gates, the company’s general manager. “It’s a challenge for all bike shares.”

Eric Bourassa, transportation director for the Metropolitan Area Planning Council, says maintaining serviceable “bike balances” “is something that is a big priority for the municipalities.” Bourassa’s council negotiated the current agreement between Hubway operator Motivate and the cities of Boston, Cambridge, Somerville, and Brookline. He continues: “It is generally recognized that there is a rebalancing issue.”

To counter the problem, Hubway runs four rebalancing vans that redistribute the bikes throughout the day. The contract with Hubway participants in the four adjoining cities calls for the vans to run between 6 am and 10 pm; while in some sense Hubway may be Boston’s only 24-hour public transportation network, Gates says riders shouldn’t expect to find stations balanced after the T stops running.

“We prebalance stations at night to be ready for the morning commute,” says Gates, explaining that residential neighborhoods are likely to have full docks in the morning while those near workplaces are going to start the day nearly empty. “If you find your station is full or empty depending on the time of day it may be because we’re preparing for the next [commuting period.]”

“The focus of our rebalancing is to not necessarily have each station be somewhere between empty and full,” adds Gates. “Instead it is focused on insuring that the most customers are the most satisfied with the stations that are most important to them. So, for example, if North Station were full we’d have a larger percentage of unhappy people than if Franklin Park were full.”

A look at the longest midday outages shows that outlying neighborhoods are especially hard hit. On Oct. 31 there were midday outages that exceeded three hours at three different Jamaica Plain stations and seven Allston/Brighton area locations, plus hubs in Roxbury, Savin Hill, Mattapan, Roxbury Crossing, the Fenway, Charlestown, and Somerville. With stations widely spread out in those neighborhoods, an outage means a user could find themselves walking an extra half-hour if they want to return or take out a bike.

Gates told DigBoston that Hubway gets hit with a violation each time one of its stations is empty or full for more than 180 minutes during rebalancing hours. But just like the fines imposed by the MBTA on its commuter rail provider, there’s a gap between the potential violations and the ones that are enforced and collected on.

“While our contract contains provisions for issuing fines if a station is empty or full for more than three hours, we have been working with the operator to identify creative strategies to address goals,” says Sandra Clarke, deputy director of the Cambridge Community Development Department. “For example, we sometimes use ‘valet’ services, where there is a [Hubway] staff person who can check in bikes when stations are over capacity at key hours.” Elsewhere, the valet system has also been used in Boston at North Station and before Red Sox games.

Asked about the violations, the City of Boston initially refused to say whether it had issued any fines. It took nearly two months and a DigBoston public information request for Boston Transportation Department spokeswoman Tracey Ganiatsos to confirm that the Hub had waived all fines. While the Boston contract is murky on what exactly would constitute a finable offense, if the $1,000/incident “failure to distribute bicycles” were levied every time a station was unusable for three daytime hours, the fines could quickly overwhelm the $52/dock monthly fee the city pays Motivate. (Participating cities collect usage fees and sponsorship dollars, and Ganiatsos notes that the service comes at no taxpayer cost other than the time spent by Boston Bikes staffers on coordination.)

Asked the same question about fines, Somerville’s public information office failed to respond to multiple inquiries.

The Hubway contract between the participating Greater Boston cities and Motivate expires in April 2017. A document sent to Brookline Town Meeting members from the town’s Department of Planning and Community Development notes that Hubway service took a hit after Motivate, which was formerly known as Alta, was bought by a new owner in 2014 and a former general manager was reassigned to San Francisco. According to the memo, “During the transition, all of the Hubway communities experienced a decline in service, including routine operational issues such as station rebalancing and in [the] bigger picture tasks such as timely delivery of new bicycles and stations to fuel continued system growth.”

But when the contract was up for renewal this fall, only one entity put in a bid to be the Hubway operator for the next five years: Motivate.

Looking for a fix, Hubway municipalities “are hoping to allow Motivate to pursue more funding through sponsorships,” says Bourassa of the Metropolitan Area Planning Council. “Hopefully if there is more revenue through the system there can be more staff as well as greater density of stations … Motivate will be required to improve the balancing of the bikes… [but] there is only so much they can do with four vans.”

In the meantime, Gates says frustrated users should feel free to “at any time communicate with us through our call center or send us an email, but we are monitoring [outages] so I’m not unaware that these stations are full.” The general manager adds, “We are also every day working towards better anticipation of future demand and better routing techniques with the hope of addressing not just major stations but every station.”

CORRECTION: A previous version of this story identified Sandra Clarke as the director of environmental and transportation planning for the City of Cambridge. Clarke is the deputy director of the Cambridge Community Development Department and this article has been changed to reflect that.

This article was produced in collaboration with the Boston Institute for Nonprofit Journalism.