Wow! That is a double whammy! Fortunately for me I coast downhill for about a mile before I have to stop. Next it's accelerating onto a state road with a 55mph speed limit. Traffic isn't usually bad when I drive in to the office, so I don't often have to floor it to get up to speed. Another mile down the road and it drops down to 45mph anyway. Then , after a traffic signal it's back up to 55mph straight up a mile long hill. The hills are an mpg killer, but luckily for me I don't have to deal with bumper to bumper traffic on a daily basis. Just try to keep a buffer btw yourself and the driver ahead of you during the carpark phase of your commute and glide at a slow pace. (I'm sure you're trying to do this anyway since you are getting 45mpg.) Keep up the good work and pray for warmer days!

Scott