“A newer approach, joint cognitive systems, treats a robot as part of human-machine team where the intelligence is synergistic, arising from the contributions of each agent. The team consists of at least one robot and one human and is often called a mixed team because it is a mixture of human and robot agents. Self-driving cars, where a person turns on and off the driving, is an example of a joint cognitive system. Entertainment robots are examples of mixed teams as are robots for telecommuting.”
I think the underlined part is very interesting case where the author used ‘is’ instead of ‘are’. I assume three possibilities for this as follows;
1) maybe the author probably lost track of the syntax due to the long intervening ‘where’ clause.
2) since the subject is a long way from the verb especially with intervening 'where' clause, he unconsciously made the verb agree with a singular complement.
3) he considered the subject 'an example of a joint cognitive system' and intentionally fronted the complement - 'self-driving cars, where a person turns on and off the driving' to stress.
Your advice would be really appreciated.