TOKYO— Toyota Motor Corp. plans to make some of its cars fully capable of self-driving on highways by around 2020, it said Tuesday, accelerating the rollout of its autonomous-drive technology and countering Silicon Valley rivals like Google Inc.

Toyota used the term “automated driving” to describe its new system, which allows vehicles to get on and off the highway and change lanes without driver input. That was a shift from its past approach, under which it preferred calling such technologies “advanced driver support.”

“We were afraid that by using the term ‘automated driving,’ people would misunderstand that humans are not involved at all,” said Masahiro Iwasaki, an engineer involved in the development of the technology.

But rival auto makers and Silicon Valley players started to use such terms frequently, and the world’s biggest auto maker by unit sales realized that it needed to market its technology differently, Mr. Iwasaki said.

“Our goal remains the same—improving mobility and decreasing accidents,” he said.