Tesla Inc. is readying a major upgrade of its driver-assistance software, but the top federal crash investigator says the move might be premature.
Chief Executive Elon Musk last week said drivers would soon be able to request an enhanced version of what Tesla calls its “Full Self-Driving Capability.” The upgrade is expected to add a feature intended to help vehicles navigate cities, expanding the suite of driver-assistance tools that had been designed mainly for highways.
