Automakers invaded the 2015 Consumer Electronics Show in Las Vegas with a record 10 manufacturers showing off wares. Among the innovations showcased were smart watches that unlock doors and gesture controls that recognize hand movement. Such technology dazzles, but the most useful advancements were far more practical. One of them was General Motor's OnStar Driver Assurance system, which predicts when engine parts might fail. Another, BMW's i Connected Mobility suite, lets users plan trips at home on their smart TV. Browse the best car tech we saw at CES in this gallery.