There are a couple of posts in Under the Bonnet on the topic of overheating, but I'm posting here to give everyone a heads up. Especially with the summer traffic jam season.
There are two cooling fans on the Mini Cooper, and on my mine at least one of them has failed causing the temp to redline in a traffic jam on the Saw Mill Parkway. The temp gauge stays in the middle as long as the car is moving. Anyway, my car is in the shop awaiting the part. The service rep told me she had had a Mini in with the same problem the day before. And the mechanic at my office said his brother-in-law had the same problem. So this may be an endemic to these cars. The Mini rep seemed to think it's the auxiliary fan that's failing.
If you smell coolant start watching your temperature gauge. Coolant smells sort of like burning pancake syrup.
The placement of gauge, itself, makes it easy to overlook.

 

Thanks for the advice! I pick up my new MINI tomorrow morning,
and want to do everything I can to keep it in good shape.