WASHINGTON — Two months after its disastrous debut, the federal website for enrolling Americans in health insurance under President Obama's healthcare law has improved markedly, and many consumers are now likely to be able to use it to select insurance plans.

Enrollment in health plans — the most important measure — has been accelerating.

But the performance of the troubled HealthCare.gov website, which consumers in 36 states are supposed to be able to use to sign up for health coverage, still falls well short of basic standards for Internet-based commerce.

Errors on Web pages and unscheduled outages remain far more common than on commercial sites. Some consumers still run into dead ends when navigating deep into the application and enrollment process, say advocates who work with the site to enroll uninsured Americans.

Moreover, while parts of the site that consumers use function much better, the complex systems necessary for processing applications and sending consumer information to insurance companies still don't function properly, insurance industry officials say.

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Ironically, improvements to parts of the website used by consumers could exacerbate these "back-end" problems. Many companies are nervous about being deluged by bad data if consumers flood the website in coming weeks to get coverage by Jan. 1.

"It's a significant concern," said Wayne Powell, vice president of Blue Cross Blue Shield of Kansas City. "If we get a deluge, assuming the website pipeline opens up, it's going to be very challenging."

In all, it is still unclear whether the improvements in the website have fulfilled the president's pledge to get the primary gateway to the Affordable Care Act working smoothly for the "vast majority" of users by the administration's self-imposed Saturday deadline.

The administration has released little meaningful data about the site's performance, largely preventing independent assessments of whether 80% of users are now enrolling online, a goal outlined by the White House.

And administration officials won't say what percentage of consumer applications are being accurately transmitted to insurers, a key measure of the site's effectiveness.

Some insurance companies have largely abandoned plans to rely on HealthCare.gov. They are now focused on enrolling people directly through their own websites.

"That just makes for a better consumer experience," said a senior executive at another major insurer, who asked not to be identified while discussing problems with the health law rollout.

In Illinois, one of the states using the federal HealthCare.gov site, state officials have advised advocacy groups to hold off on attempts to enroll people through HealthCare.gov until later in December.

There are fewer problems with most enrollment sites operated by the 14 states that do not rely on HealthCare.gov, including California. Enrollment in many of these states surged during November.

The number of people able to get health coverage through the federal site has also ticked upward, although the administration will not release November totals until later this month. Fewer than 27,000 people chose health plans in the federal marketplace in October.

The White House hopes that 7 million people will ultimately use one of the federal or state marketplaces to get health coverage for 2014.

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According to accounts from around the country from insurers and groups that work with consumers, HealthCare.gov works far better than it did in October, when it was barely functional.

The University of South Florida, which is helping residents of that state sign up for health coverage, was able to use the website to enroll more than 71% of the people who got coverage in November, according to Jodi Ray, project director.