I have a 2003 Corolla. Should I have Metric or NIST (American) emergency tools in my trunk?
Not much you can fix on the side of the road these days, but a 2003 Corolla has to be metric. Maybe Torx screwdrivers to replace a bulb.
Yeah, I kinda agree but you may run into some SAE sizes. I always carry both. What you need is a cell phone most. Then have the tools and supplies for specific repairs such as replacing the serpentine belt, wheel lug nuts, fuses, maybe hose repair, flash light, etc. Blut right, not much you’re going to do on the road. Prevention is best.
Things @Bing lists, plus a portable air pump (to avoid using the “donut” spare if possible), a jug of water, a quart of oil, a roll of duct tape
A tow strap.
A (PAID) AAA card works well for me.