In the official EPA highway test
they start from a 'warm engine' stop
and slowly speed up to 56 mph
{supposedly like going on an Interstate on ramp}
then the vehicle slows down from 56 to 55 mph
and holds this speed like shown below:



then the vehicle coasts down to a stop
{supposedly like going on an Interstate off ramp}

Note that at only 748 seconds long
at an average speed of about 47 mph
this highway test trip is less than 10 miles long.

If most Rams drove this slow
they would get the 'official' EPA highway MPG rating too,
but don't most Rams you see go 75-79 mph?

More information,
including the new 2007 EPA changed test, which is
'faster speed with AC on'
at this weblink:

http://www.fueleconomy.gov/feg/fe_test_schedules.shtml

 

Consider a few things about fuel mileage:
1. To really see the max fuel mileage you can get, cruise at the lowest RPM you can in overdrive. For my truck, this is about 44 mph. With 3.22's, it cranks at a little under 1500 RPM. Obviously this isn't the most practical since no one drives this slow on highways that are posted 55 mph+, but it'll just give you an idea on your truck's true MAX mileage
2. Cruise control is nice, but not perfect. Sometimes it's best to give it some a little extra throttle (Keep the torque converter locked up) if you are going down a hill and then must go up a rather steep hill so you don't have to shift down going up the hill. This saves gas and engine/tranny wear. The extra momentium built up doesn't cost as much as shifting down to keep speed constant.
3. Across all the years, options, people's taste etc., a lot of specs differ, i.e. ground clearance, condition of the engine and tranny, even the type of tires you have (not just size but tread). A Ram that is 2" higher than another is going to be fighting the wind a lot more than you think @ 70 mph+ (I'm all for raised trucks, don't me wrong). Gas mileage is going to very, but getting 20 mpg on the highway @ ~65 mph isn't difficult with any of the Chrysler V8's. Sometimes just driving smart (aka efficient) can get you and extra mpg or even better (depending on who you are comparing too, lol).
4. You have a full-size truck! MPG is definitely not our biggest worry or we'd have a 4 cyl. mid-size truck or car. It is a trade-off for having the (in my opinion) most American and (obviously) tough vehicles on the road.
5. Temperature and where you get your gas makes a bigger dif than you think. "Winter gas" tends to drastically drop mpg.

 

My wife and I have an 06 Dodge 1500 Quad cab, with the HEMI. The Hemi gets better gas mileage then the 4.7 litters check the window stickers. My wife and I just moved 1600 miles and my wife averaged between 21 and 23 miles to the gallon. The mileage read 23 miles to the gallon at the end of our trip. My wifesaverage speed was around 70-75 mph. More power and better gas mileage not much thought to it. The gas mileage sucks on 05 and prior though.

 

Interesting dodge07man. If only my truck was 2 years newer. Obviously you weren't pulling anything when you moved, correct?