Ford CEO Jim Hackett Tuesday joined the growing ranks of vehicle and tech execs willing to say publicly that self-driving cars won’t arrive as soon as some had hoped.

The industry “overestimated the arrival of autonomous vehicles,” Hackett told the Detroit Economic Club. Though Ford is not wavering from its self-imposed due date of 2021 for its first purpose-built driverless car, Hackett acknowledged that the vehicle’s “applications will be narrow, what we call geo-fenced, because the problem is so complex.” Bloomberg earlier reported the comments.