Fuel consumption due to the temperature drop

andyprius - I understand what you say, but I need to be more clear on the type of "highway" you drive between Munich and Florence.

From Munich (519 m/1703 ft) to Kufstein (499 m/1637 ft) via Rosenheim area (440–470 m / 1,444–1,542 ft), you *have* to drive 140-150km/h to keep up with traffic - otherwise you are an impediment (or a truck/lorry) - and the highway goes up & down & up & down with very few flat areas. When going "down", you cannot really coast as the wind and roll drag at these speeds is high enough to slow you down to quickly. Down means a slope of no more than 5% on average. Anything more steep, will mean a speed limit of 100km/h.

From Kufstein to Innsbruck (574 m / 1,883 ft) it is essentially flat since you are driving through valley.

From Innsbruck to the Brenner Pass (1,370 metres / 4,500 ft) it is quite steep, but still you are allowed to drive 100km/h and in some sections up to 130km/h, and surely you are not saving gas.

From the Brenner Pass to Verona (59 m / 194 ft), it is "downhill", but over such a distance (230km/143mi), that you cannot coast - you need to give gas to keep the speed of 100km/h (until Bolzano 262 m / 860 ft) and then 130km/h after that.

The only real flat section (150km/93mi) is between Verona and Bologna (54 m / 177 ft), but there you have to drive 130km/h to keep up with traffic (that's the speed limit).

After that to Florence (50 m / 164 ft) 100-110km/h max, with sections uphill at 130km/h, but in between you go all the way up to 600 m / 1968 ft.

Also, a difference between Germany/Austria and Italy is that in the latter there are way more tunnels in mountain/hilly areas, otherwise the climbs would be way too steep for a highway. This means that on average the climb is always less than 5%, but constant for maybe 40-50km.

 

After averaging low 50s mpg for the first three months in my Gen III Prius, I am now averaging in the mid 40s. I noticed a dip when the temperatures dropped below 50 degrees and another drop off when the temperature dipped below 34 degrees.

I agree with the explanations that have been provided in the various posts. One that I haven't seen: That the reformulation of gasoline for winter weather has a negative impact on fuel economy. Seems plausible.

In any case, if other (non hybrid) vehicle owners had the same tools that Prius owners have to constantly check fuel economy, I would expect them to be complaining, too, about fuel economy decreases in the winter.

I can live with 45 mpg in the winter because I know I will be 10 mpg higher come May.

 

Hello Pakett, I understand totally what you are saying. I have driven that route and driving in Italy is somewhat different. However all of Europe is somewhat similar as far as speeds go. Last time I was in Germany they had passed a law of NO flashing of lights at people in the left lane, when they are in the act of passing. Also trucks pretty much MUST stay in the right lane and also the assumption of fault should an accident occur and you were driving over 130Km/Hr and were involved. These were BIG changes and I noticed that the Germans were much better drivers than previously. Are the laws still basically the same? ........if so, I observed driving an old VW Bug diesel I could easily obtain 50mpg. And on the freeway I had a great excuse for getting behind a truck and driving a liesurely 50-55 MPH. Of course I was a tourist and enjoyed the scenery. I still drive about the same here in California, stick to the right and put my cruise control on 55. I love hills because I can boost it then to about 60MPG. Let's face it you were driving 95MPH because you wanted to and it was fun! Don't misunderstand me, I am not being critical. I never allow the driver behind me to force me to go faster. Rather I look for opportunities to conserve and mostly to "Get there" To overdrive the Prius is a sin, and Toyota will not be happy with you. Anyway ty for your reply. Macht Spass.

 

In all EU countries, as far as I know - there might be some country specific minor differences, you must keep right when driving on all roads.

On an multi-lane road (ie highway) you have to drive in the rightmost lane if empty. That is, you cannot overtake on the right. There are a few exceptions to the rule, most notably in what are called "multi-lane, high capacity" roads, most always in cities/towns, where you are allowed to overtake on the right.
It is "fashionable" (because I don't want to write anything worse) to keep driving in the left lane or in the middle lane (when 3 are available) driving at 100km/h and not overtaking (ie even when there are no trucks in the right lane or the right lane is simply empty). It is considered to be a "looser" if you drive right, it is cool to be in the middle, "the road is mine" approach - too bad it is also illegal and sometimes dangerous.
Too bad also police does not check (especially in Italy - actually where is the police at all on italian highways?), and no signs remind you to do it - the only signs are ads for subscriptions for highway toll, phone numbers for (long gone) traffic problems, or maybe, sometimes, to remind you to keep the seat belt buckled....

Also, you are not allowed to flash lights, always and on the highway in particular to the preceding driver especially on the left lane to ask for right of way, "the road" - so to say.
This is valid in Italy as well as in Germany. In the former case, many don't follow the rule and it is particularly irritating when they are doing so and you are overtaking while driving at the limit - essentially they want you to give way for them to speed, often "forcing" you to speed to end your overtaking more quickly.
In Germany, it happens seldom that they flash, but at least in that case they have a "right" to do so, since they are allowed to drive faster, if they can. A kinder way to ask for free road in the left lane in Germany, is to keep the left blinker on, meaning "I am coming fast - move out of the way". If you are overtaking though at 130km/h a truck on the right lane, that is, you are doing so without really stopping traffic (any traffic above 130km/h has no right in that sense), in Germany drivers tend to simply brake and wait patiently that the driver has finished and moves back. Moreover, in Germany, drivers tend to go quickly back to the right lane if empty.

Yes, it is still valid, to my knowledge, that if you drive faster than the advised speed limit of 130km/h in Germany, you are immediately considered (partially) guilty in case of an accident, even if it is not due to your driving (ie it is not your fault).
Since speed cannot be used to fine drivers in sections of highway with no speed limit, one way to check for the police is the distance drivers keep between them and the preceding car, in order to brake safely to a stop in case of emergency. Almost never people truly understand what that means "keeping safe distance" when driving 170km/h or more - it is illegal, even more so when well over 130km/h, to tailgate a car. You need a *lot* of distance between cars.
In Italy drivers like to tailgate to "put pressure" on a preceding car - not understanding that not only it is dangerous, but if you brake and they hit you, it is THEIR fault and not yours...

Also another way to check traffic and drivers' behaviour in Germany, is to put cameras all over the place when there is a speed limit section (e.g. with 120km/h or less, say in case of wet roads, tunnels, bridges, roadworks, sharp bends, or declines).

Overall in Germany they drive way better and safer as in Italy, but I think it is mainly due to fear of the police. That in Italy drivers drive recklessly is a fact - and not just on highways. They simply drive badly - Myself, being Italian, I must admit it - as well as the fact that there are too few checks. In Italy signage is considered to be an advice rather than something you must follow - though often it is nonsense signage, with even more nonsense speed limits that it is almost impossible to follow (ie "forgotten" 60km/h limits on 3-lane straight highway sections are very common - nobody follows these limits, *nobody*). I find signage in Germany instead to be very appropriate and most always meaningful. Too many signs maybe (even the germans complain about it), but *way* better than in Italy.

I have seen many cars with german license plates in Italy driving recklessly ("they never check") and the other way round for cars with italian license plates ("they check continuously"). Actually in the latter case, drivers that tend to speed in Italy, drive like grannies in Germany where they could actually drive at 250km/h if their cars could.

It is not a "sin" to drive a Prius fast in Germany (where allowed!) if you do it once in a while for "fun" and if you do that knowingly. If you do that on a regular basis and complain about fuel consumption, then it is really a sin and you would have a much better time with a 250HP car....(that would consume, BTW, 3x more... )

 

Hello Pakitt, Thanks much for your very complete synopsis of driving habits in both Germany and Italy. Your English incidently is flawless. Glad to hear the Germans are still driving relatively sensibly. Cheers Andy.