Here is yet another opinion, but has worked for me. I am always learning new things about how to get better FE, and my experience over the 5,400 miles I've driven the car has shown I keep doing better. The 10 tanks I've used since getting the car average is 46mpg (my wife killed the mpg on the first 3 tanks sitting at 38mpg), but my last 5 tank average is 51mpg, and my current tank is about 53mpg. I am in no way an expert on the HCHII, and am still trying to figure out how some of these super hypermilers get 70+mpg!

There are 2 forms of assist - ICE Assist and EV-Assist. The first is using gas, the second is not. Here is when each is used:

ICE Assist - When you are at 0 and accelerate from a light or stop sign, depending on your battery state of charge (SoC) you will see the white assist lights appear - any variation of 1 to 8 bars depending on how hard you are accelerating as well as the battery SoC. You are using gas at this point... the assist is increasing your torque to help accelerate, with the major portion of acceleration coming from the ICE. Also, you will see the assist lights appear if you accelerate say from 40 to 50 depending on how quickly you are trying to accelerate, or when you're going up an incline. ICE Assist can be a quick drain on your SoC.

You will hear 2 sides of a story around here 1) Accelerate quickly to your cruising speed then let off the gas and coast/cruise. This will use the ICE Assist to it's fullest to get you up to speed. 2) Accelerate gradually keeping your RPMs under 2,000 (1,500 if your good). I use the latter because I can keep the iFE above 40mpg while accelerating gradually. Plus if I see the next light turn red, I let off the gas and coast to the light without having to waste the gas getting up to the speed limit! I have tried #1 and the iFE sits at 5-10mpg and I can sit and watch my current mpg drop quickly.

EV-Assist - When you are at the speed limit or cruising speed and you can "switch" to EV mode (valves closed/ICE disengaged, iFE pegged at 100mpg, no fuel being used), you can use the assist lights to help maintain speed, or help reduce your deceleration. You will only be able to get up to 4 assist bars. If you try to go above 4 assist bars, the ICE will engage and you will be using fuel again and your iFE will drop. There are some circumstances where you can get a 5th assist bar while in EV mode, but you probably won't be able to do it under 55mph.

I do avoid using my brakes as much as possible. You get better battery regeneration if you let off the gas and see the green assist lights vs the same number of lights when pressing on the brakes. I am constantly watching the traffic lights ahead of me... if one turns red, I take my foot off the gas and coast to the light. 7 out of 10 times I never have to stop completely - I will get down to 15 or 30mph and coast in behind the car in front as they are accelerating from the now green light. Also, LEARN YOUR DRIVING ROUTE WELL. What I mean is I can guarantee I know when at least 4 lights are going to be red on my route. I know how I can beat them (by accelerating from 45 to 48), or know I don't need to get up to the speed limit because there is no way to make them, so why waste the gas. It's hard with some of the small street lights to know if they are going to turn on you, but major cross street lights are usually on a "less-variating" timer based on time of day and traffic. Nights and weekends don't always apply because they can be set for "first come-first serve traffic". I drive 7 miles each way to my regular job, and up to 25 miles to my side jobs. In my 7 mile commute I hit 4 stop signs and have 12 traffic lights to hit or miss. At the stop signs, I put my car in D2 when I'm at 10-12mph which will stop the engine from going into Auto Stop. Auto stop is good as long as you will be stopped for more than 6-10 seconds (this buffer is needed to make up for the fuel used when restarting the engine from Auto Stop). I have most of the lights timed pretty well. When I'm at work I have to get the mail at the post office so I drive about 3/4 mile each way to and from the post office. I then occasionally take a short 1-2 mile trip to get lunch. You'll hear a lot of people around here say "If you do short distances, you won't get good mpg". I think I'm doing pretty darn good for all my short distances, not to mention the slight hills and all the stop and start at the lights. You can too!

Search for my other posts where I have put in some helpful information. And also be sure to read the HCHII Bible - I mean Tarabell's HCHII writeup!