The wooden auto ramp is made from 2x10 lumber and deck screws.
Works well for Toyota Prius & Kia Sedona minivan.
Ascending and descending are smooth with tapered slop. I've been using it since early 2018; it's rocksolid and dependable as of 2023. Worth every penny. Heavy but stable, economic, and sturdy. Nontoxic. It is more functional than cheap consumergrade plastic ramps.

SAFETY FIRST: Please consider using jackstands as a backup. Store your ramps in a dry place to avoid any wood rotting.
Each weighs ******* 47 lbs.******* Use caution and proper body mechanics to move them. Avoid lifting them as much as possible. Consider using a delivery cart to move it.

Materials:
Fivestep ramp with about 7.5 inches height:
Bought 2 in. x 10 in. Doug Fir Lumber studs.
I bought two 8' studs and two 10' studs to make two ramps. Home Depot will cut it for you.
Board length: 20, 28, 36, 44, 52 inches (before the taper is cut).
I used 3" countersink decking screws from Home Depot to screw the boards together.

How to build:
Home Depot will cut the lumber to size. I cut rough a 12degree taper with a circular saw and final touchup with a hand chisel and sander. The taper is slightly rough; which actually provides better traction than a smooth surface. A basic hand saw would do just fine also; a hand saw is probably safer (but more timeconsuming) than a mechanical saw. Screw together one step at a time.

How to cut taper:
For each piece of wood, cut a 12degree taper as noted in the image below. See the image for measurements:
https://photos.app.goo.gl/PrHigypaVxr...

Enjoy.