So I had bad luck today, I had a little rock star crack on my parent's ES300 windshield and because I had the defroster on with heat and it was cold outside the crack started to get bigger. The crack almost spans the windshield now. I am getting it replaced tomorrow but I still need the car to get home and to the windshield repair place tomorrow. How safe is it to drive the car with such a large crack and is there any precautions I should take in order to keep glass out of my face?

If the crack goes from one border of the window to another, then it's bad.

You can try driving in reverse to the windshield repair place...

Honestly, if you think that it's not good, then it most likely is not good. Get it towed.

Worst case scenario is that it won't shatter unlike all the other glasses-I don't think.
If the lines will get worse and worse, it may make visibility hard to see.

I had my sister's civic windshield replaced last week. I stood there and saw the guy took the window out. He applied alot of force in getting it out and made a couple new line cracks-nothing exploded

There are 3 layers: glass-laminate-glass. That keeps the glass from shattering.

Duct tape for now? haha.

I forgot about that. So basically I just don't want to get into a rollover accident. It's only for a day that I don't get it repaired, they have to get the glass in stock first. I don't drive on the highway to get to work and I'm a very cautious driver (helps save gas to be light on the throttle and brakes ).
So I don't think I'll have a problem with the windshield caving in or anything.

I've been doing research on it and it seems that if you are to replace your windshield to make sure they do it right, they have to remove the necessary pieces to set the glass down right. They have to use the correct glue and allow it to cure the full time recommended by the manufacturer. It's recommended to get it done indoors in weather that is below 40 or the humidity is too high (so the glue can set properly).

FYI, it is a ticketable offense (view obstructed), if a cop see's you, you're likely to get pulled.

You are perfectly fine to drive for however long needed to get it replaced. SAFELITE* is who usually makes everyone's windshields and this glass has been designed to hold together in any situation.

People have rammed tree limbs through windshields and just a hole where the part went through is the only part that failed. The rest of the windshield is still just sitting there.

The glass making process sandwiches an adhesive sheet between two sheets of glass making it nearly impossible for the glass to "shatter". It just webs and sticks together. It's not a sheet of glass like it appears. It's layered glass held by many different polymers inside the glass with all the air vacuumed out to make it clear.

There is ZERO chance of any failure issues occurring with a cracked glass.

I'm aware of this but it's low on the windshield hopefully low enough where cops don't think it obstructs my view.
I can't really help quicken the process and hopefully the cop (if I get pulled over) doesn't give me a hard time since I have an appointment set up to get it replaced.

Drive the car to the repair place...

when I had a disaster happen with my Land Cruiser two years ago (flying concrete disk in the carpool lane--no way to avoid it) it literally made a donut crack in the windshield--and it was fine.

and also, look in your area for guys who COME to replace your windshield. When I got the windshield on the LC replaced they came and did it at my place. Usually local body shops can point you out since they have to outsource for glass anyways most of the time.

I am? They don't have the glass in stock so they have to overnight it. So I have to wait til tomorrow at around 1:00pm to get it installed. I'll drop the car off for the time they need to install it and let the glue cure. And come back later to pick it up.

I would get it installed at my work but it's too cold in MA right now (sub 40 degrees usually). They won't install it outside if it's too cold or if the weather is crappy (snowing/raining). The glue won't cure correctly in cold weather.

Fuzzy dice, hanging x-mas tree air freshners hanging from the mirror is deemed an obstruction. You will be fine.

Funny thing, I've been pulled over for having fuzzy dice and was told to take them down. Hopefully I'll have better luck for the next 20 hours or so. Of which only about 1 hour of it will be spent driving.

Just get it repaired ASAP.. Good luck

You should be fine. I drove around with a crack on my windshield for half a year. It was in a backwards "L" shape from my mirror on the windshield(whatever its called) to my drivers side mirror. It was an obstruction at times since the light would reflect off the crack into my eyes. My dad was very very stupid at the time and decided to wait until it went the whole way so I decided to get it changed sooner by hitting it one day with my palm. It was increased and I told my dad I was scared that it'll burst apart and...it worked, it was replaced within the week

Dad is quite stingy so the worst has to happen before he fixes it -.-"