Yup. Allison and Eaton both make automatic transmissions for big trucks, and they're getting very popular.
Yes, 18 wheelers have 18 wheels.Some tractor trailers have more, some less.
Some of them do.
Anywhere from five to 18. The military M915 has a five speed automatic transmission. Most major fleets run 10 speed transmissions.
Yes
The statistics are not broken down by that category (i.e.: 18-wheelers, 10-wheelers, 6-wheelers, etc.). They are all classified as "commercial" vehicles.
# no way.
There are a variety of different advantages of 4 wheelers over 3 wheelers in terms of vehicles. Some of these advantages are that 4 wheelers are much safer than 3 wheelers.
Yes
If you mean cruise control, yes.
No.
Steel or aluminum.
Two or more.