Yup, people would basically roast in there. Thankfully they'll probably pass out first due to suffocation and not feel the pain of being burned. Would have been less problematic if it were trains since the moment the electricity shuts down, the train would just stop.

IMHO our innovators should be focusing on improving public transport. This is why I prefer that people live in cities rather than suburbs. You can go around without having to use your car. In the better designed cities, it's even possible to just ride a bike or walk to work.