How dangerous is it for two 20 year old females to drive from New Jersey to California ?

The biggest danger will be driving while exhausted. Long haul truck drivers are legally required to take a 10 hour break from driving, and they are very familiar with the highways they drive on. For two inexperienced drivers to be taking only 8 hour breaks, while driving on highways they've never been on, and sleeping in a car which is one of the least comfortable places to sleep? I doubt you will be able to sustain this for more than 2 shifts. Please consider adding more time to your trip and stop for the night at a motel. If you can actually drive for 8 hours straight, between the both of you that is 16 hours a day, then 8 in a motel room, which is a lot more sane. Your other fears are manageable. For traffic, try to schedule your driving so that you drive through major metro areas during the middle of the day, or the weekend. For drunk drivers, just be careful late at night, and keep your distance if a car is driving erratically. Car jacking? I only hear of that happening in rough neighborhoods, not on interstates. People preying on females can happen anywhere, even in your hometown. Follow your gut, if a place seems sketchy, get out of there. Stick with your friend when you are at a stop.

You should be ok. I've done that trip but I'm a dude. Stick with I-80 West for the majority of your trip. You don't want to drive the "southern route" along I-10 West. I think it's not as safe. Be careful where you stay the first night. Chicago is 12-13 hours from NJ, so it could wind up being your first night stop - but try to avoid that. Either stop sooner or later than Chicago. Good luck and enjoy. Plan a stop at the Grand Canyon for a day. You won't regret it.

Driving anywhere for 43 straight hours is extremely dangerous and foolish. 8 hours is a very long stretch to drive and neither of you will get the proper amount or quality of sleep to make you safe behind the wheel. You will be endangering your lives and the lives of people driving around you. Plus, why would you waste such a rare opportunity to see the country? Why not plan to do it in a week or so and map out all the cool things you could stop and see along the way?

8 hours behind the wheel is way too long, switch off every 4 - 5 hours, and forgot about not stopping. Pull over at a rest area for at least 5 - 6 hours of sleep, many of the larger truck stops even have showers (paid) . Bring a cooler for beverages, food, and some snacks....sandwiches work well for your first day, then fruit and nuts, etc...... Try to break it up in to 3 days of travel , I agree with "A Hunch". If your get 14 - 15 hour of actually driving per day ( 42 - 45 ) you will be there in 3 days. So say 15 hr driving, 3 hr misc ( gas, food, potty ) & 6 hr sleep.