The driveway was not compacted properly when installed and the base has sunk.
It's a small job and they still need to bring the machines(roller, etc). I would guess $500-1000. Call and get some estimates.

"Obviously this can't be good for the floor, car or tires when you bump into this mini cliff every day."

Since you are not driving at high speed here it is not going to harm anything.

It will damage the concrete, though.

My dad built an asphalt ramp in a very similar situation, using bags of cold mix. It worked very well, although he is an engineer and pretty good with that sort of stuff.

You could also consider some sort of wooden ramps, if you did them nicely they wouldn't look too bad.

You may want to caulk the crack to keep moisture out.

"It will damage the concrete, though."

If the concrete was not well mixed and worked it may cause cracking at the corner, but that cracking would show up even without the small step.

Rubber tires are low speed are plenty flexible and there is no impact loading (like happens when you hit a pot hole at 35 MPH).

What you describe is very common.
Keep in mind that this might have been done intentionally to allow for rain water to not get into your garage, especially if there is high winds that can blow the rain under your garage door and into the garage.

On that note I have seen some hard plastic style ramps that you can purchase, cut to length and join them together with clips that are on the bottom side. They were about 2 to 3" tall and only about 4" wide, sorry but I have no idea where to find them.
best of luck chris

Or you could do something like this:

Here is a link that might be useful: grate

I've seen concrete edges fret from foot traffic so I have no doubt car tires can do it too. I agree the quality of the concrete comes into it, and how well finished it was, but there's every possibility it was not the best concrete job. I've seen more bad jobs than I have good.

I agree it's important to consider the drainage, you don't want to create a new problem.

I might be cheap and try some rock and/or sand in the valley - lay down a pressure treated 2x12, maybe stain or paint to blend in... stake it down. Then I'd bump up and down the step easier. Possibly angle cut or router the corner off one edge some.

What has worked for me....for 8 bucks, you can buy a bag of cold patch. Use a block of wood and a hammer and work it into the joint. Once you get near the top, use a little kerosene, diesel fuel or even charcoal lighter on the block as you tamp it in. It brings the aggregate closer together and makes for a very smooth surface. In the areas where you drive in and out and the weight of the vehicle might leave some indents, you might have to add another layer. This would happen usually during the summer where the heat softens the asphalt a bit and allows it to give. I never noticed it the first year but the second year, they showed up ever so slightly.Before filling in the indents, use some asphalt primer or tack coat. A small bottle of crack filler solution would work. That allows permanent bonding between the old and new. Then tamp it in like mentioned before. The next time you seal coat the asphalt, it will all look the same. I used this process about 5 years ago and it did the job with no regrets.

You might want to consider using ramps for garage entrances. I have been using the Electriduct 4.3″ garage ramp and it works well for me. You might want to check this article for recommendations of quality garage entrance ramps and find out what product best suit your needs: https://www.mechanicalcaveman.com/best-ramp-for-garage-entrance-review-driveway-lip-parking/

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