Game Dev here, everybody calm down!
Now, here's the thing. Unlike making a racetrack, where it would be beneficial to have multiple people working on the track, props, textures, etc, modelling a car and doing all that work is fine as basically a one-man job.
This concept is not a bad thing - especially when you look at it logically. They've said it's one person modelling each car. It's not impossible, I've done it before myself, and the workflow is A-OK.
This can be assumed to mean:
3d modelling of the bodywork
3d modelling of the interior
3d modelling of external parts (wheels, tyres, body kits, etc)
This can be assumed to probably/possibly mean:
Reference-gathering (photos, 3d scans, manufacturer data)
Paint and Colour-matching for materials (default paint options)
Texturing for any liveries (if applicable)
Rigging the driver (placing him into the seat and hands on the wheels/gearshifts)
If you can do the exterior of a car, the same techniques can be used for the interior - there's no new technical skills. Same for wheels and other parts. Reference-gethering, apart from having to deal with manufacturers, isn't rocket science, and it cna help because you can identify which parts might cause you grief and get more shots of them. Material creation, likewise, isn't too difficult; Polyphony already has the best car paint shaders out there, so it's a case of getting reference shots of all the car's colours and fine tuning about a 15 values, made even easier if the manufacturer provides some of that info. Texturing for racecar liveries is pretty simple and fun, and relies on good UVs for the car (think of it as unwrapping the car, paint it, then wrap back on). Placing and rigging the driver should actually be fairly easy. There'd already be a driver model and animations available, so place him in there, rotate limbs to be in the right spot, set up the placement and rotation axis of the steering wheel, and set the gearshift locations- the rest should automate itself. DONE.