A new study to be released this month by Nielsen on behalf of Syniverse, a seller of roaming software and services to 900 mobile operators, including Telefónica and Vodafone in Europe, confirmed that the fees were still an obstacle — despite price caps and text messages warning consumers that they were racking up charges.

In a survey of 13,000 consumers in 13 European countries obtained by the International Herald Tribune, the study found that on average 56 percent of cellphone users either limited the use of mobile Internet or turned off the roaming function on their devices entirely while traveling within the European Union.

Danielle Jacobs, chairwoman of the International Telecommunications Users Group, an association in Driebergen, the Netherlands, that represents telecommunications user groups in Europe, South America and Asia, said Europe’s system of roaming fees was slowing the adoption of cloud-based mobile services, especially those used by business travelers. “Intug would be very happy with the abolishment of roaming fees in Europe,” Mrs. Jacobs, who is also the chairwoman of the Belgian users’ group, Beltug, said in an interview. “The uncertainty about mobile data roaming prices and the possible bill shocks are putting the brakes on using more mobile applications.”

Mrs. Kroes’s push to eliminate the fees faces hurdles. The European Parliament must support her plan, as must the Council of Ministers, which comprises representatives of each member state and is where telecommunications companies exert greater influence because they are large employers.

Pressure for change is building in Brussels. On July 9, members of the Parliament’s Industry, Research and Energy committee voted unanimously to end roaming fees by July 2015. The full Parliament is scheduled to take up the issue in September, when Mrs. Kroes is also expected to present details of her plan to lawmakers.

One lawmaker, Paul Rübig, who was a sponsor of the original roaming price controls that took effect in 2007, said that the momentum to end roaming fees had reached a critical intensity in Brussels.

With elections for the European Parliament scheduled for May, Mr. Rübig, a representative from Wels, Austria, said lawmakers were well aware of the possible political gain from banning the unpopular fees. According to Mr. Rübig, a survey this year of voter attitudes before the E.U. election showed that the top issue for Austrian voters — more important than basic freedoms and other civil rights — was the abolition of roaming fees in the European Union.