I know that 45mpg is expected for mixed driving. If I exclusively distance hwy drive what would the most accurate mpg be

I have yet to see any car get what is said on the sticker, these figures are basted on a BS system(The tests are ran on a "treadmill", the city test have some stop and go and the highway has very little stop and go), I used to have the site for all the explainations. BUT staring with some models and going to all next year there is a "real world test" that have given much more truthful results. This is the Canadian page: http://oee.nrcan.gc.ca/transportation/tools/fuelratings/ratings-search.cfm?CFID=15442222&CFTOKEN=81817707 the results came be in metric or standard. The US results page is here, I found it. http://www.nhtsa.dot.gov/portal/site/nhtsa/menuitem.43ac99aefa80569eea57529cdba046a0/

Aquick answer is 38-40MPG, My brother is a service Manager for a big Toyota dealer here, That is what he said.

We have a 2005 Prius with over 45,000 miles on it already. As you have heard we get around 45 mpg in mixed driving. We have done a few long trips on the highway - over 300 miles - and typically get around 50 mpg or so. It really depends on how fast you go. If you stay below 70 mph you should get around 50 mpg. HOWEVER, you will not get this if you drive only uphill at 70. We typically visit the folks that live about 50 miles away. On these trips on SoCal freeways we average about 50mpg for the total 100 miles.

I drive mostly on HWY about 20 miles each way to and from work... and I average around 45-47 mpg! And I don't drive like a typical "Prius Driver"...

I get more on the highway because of the hills out here. I get a nice 60MPG at 65mph and around 70-80 at 55MPH

On interstate hiways I have been averaging over 55 mpg. I drive with a light foot and lots of cruise control.

I get round to about 50 - 55 mpg. This is in Finland during winter.