apple maps seems to have caught up to google maps, and while no doubt both have the occasional problem like Ragnar mentions, either are lightyears ahead of standalone solutions like Garmin or your car-supplied nav

Actually, my car one has been pretty darned good.

2018-08-17 08:36 from wizard of aahz
Actually, my car one has been pretty darned good.

Mine is good in general, but its real-time traffic functionality is its achilles heel; horribly weak, Apple does way better.

I've got the Sirius Traffic integration with my GPS so it's been good. I compare it to Waze and it compares well with traffic and redirecting.. But it doesn't tell me where the police are by the side of the road.

so, I have carplay in my car, and for some things it's great, but for others I prefer the ford map program.

"It uses technology from traffic information titan Inrix, which supplies BMW and most other automakers as well as aftermarket navigation device suppliers and smartphone nav apps with data. The company aggregates data from DOTs and other governmental agencies and millions of bprobeb vehicles and matches it with historical traffic patterns as well as live events such as concerts that can cause tie-ups."

-- https://www.wired.com/2012/06/inrix-real-time/

If the system in my car is representative of the real-time traffic on most other carmakers, it's supplied by Inrix and it's horrible.

The data is bad (e.g. on a recent trip upstate, I drove straight though a "red" section of I-87 north of Albany and didn't even encounter a single other vehicle, work zone, or accident.
The coverage is spotty (turn on the Traffic Flow highlighting, and you'll see that NYC side streets and other minor roads don't have any information available, and never will because they're not "enabled." Nonetheless, the system wants to detour you onto such roads. It thinks they're better - because it assumes the default - but in reality it has no way of knowing.
The search algorithms, running on the local CPU in the vehicle, are weak; may fail to find a good route even when the available data would have made it the right solution.

Even different navigators that use the same map sources will give different routes; for example Google Maps and Waze will plot different routes to the same destination even though they both use the Google Maps data.

The obvious next step would be for someone to build a navigation system that aggregates multiple sources of mapping data and/or turns every driver into a "crawler" supplying data back into the system.

I suppose ten years from now, having a car without a big upright screen will be as rare as having a car without power windows is now.