The number of connected cars on the world's roadways will increase at a 57 percent compound annual growth rate to total 420 million by 2018, according to a new report from the think tank IDATE.

In 2013, the number of connected vehicles produced totaled just 45 million.

Currently, there are three main technical solutions for producing connected vehicles, which are defined simply as vehicles equipped with internet access.

The most obvious solution -- and the most advantageous from a technical standpoint, according to IDATE -- entails integrating a connection module directly into the vehicle.

Another option relies on smartphone tethering for internet access. Finally, a third method combines the first two, enabling the use of an embedded module for certain practical applications (GPS, traffic alerts, etc.) and smartphone tethering for info-tainment features.

IDATE predicts that the embedded module solution will become the most common one by 2018, accounting for 222 million of the connected cars in circulation by then.

The study echoes earlier predictions that cars will soon join PCs, smartphones and tablets to become connected terminals in their own right.