The Magic of the Prius

<div class='quotetop'>QUOTE(PriusTouring07 @ Jul 23 2007, 12:57 AM) [snapback]483470[/snapback]</div>

So you're saying you *do* weave through traffic, cut other people off, etc. in other cars?!?

Is the point of this post to comment on how responsible a driver you are in a Prius...or is it to dazzle us with tales your supra-legal exploits?

1/3 of the post is devoted to the former; 2/3 to the latter.

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Please *only* drive the Prius from now on. Some of us are actually appalled with stories like yours, even though it may be difficult to believe.

 

<div class='quotetop'>QUOTE(local_host @ Jul 23 2007, 07:11 PM) [snapback]483838[/snapback]</div>

a fair theory but a redundant one if every one drove at 60Mph to gain better effeciency?

 

<div class='quotetop'>QUOTE(local_host @ Jul 23 2007, 08:11 PM) [snapback]483838[/snapback]</div>

Actually I was involved in one these accidents. After turning onto a three lane road, I was in the left lane doing about 40 mph with a stop light 400 yards ahead that had turned red and was at least 30 seconds from turning green. So I did what every Prius driver does, let it coast. This instantly caused the driver behind me to hit the gas, gun out from behind me and promptly ram the car stopped in front of him in the middle lane. Fortunately, he floored the brakes before the impact and slowed down enough to make it a major fender bender instead of an air bag deployment. I felt really bad for the innocent driver rear ended.

So yes "too slow" can be a "main" cause of traffic accidents, but I hardly belive the solution is for me to floor it at green, and floor it at red as the "safe" way to drive.

 

<div class='quotetop'>QUOTE(local_host @ Jul 24 2007, 12:11 PM) [snapback]483838[/snapback]</div>

Yes I've heard it, on many occasions, and I can tell you it is complete nonsense!

The simple facts are that regardless of the type of road and type of car a 5% reduction in speed results in a 10% reduction in crash likelihood and a 20% reduction in fatalities. That's it, end of story. Doesn't matter how you slice or stack the data.

There's always someone who tells me that their next-door neighbor's wife's cousin once owned a slide rule and worked it all out that you are safer going faster than the surrounding traffic because you spend less time on the road and therefore your exposure to risk is reduced or something equally silly.

They are wrong. The finding is published, peer reviewed, replicated, ad nauseum.

 

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Jul 23 2007, 09:59 PM) [snapback]483861[/snapback]</div>

Hi FL_Prius_Driver,

You, and the action of coasting (maybe a drop of 2 mph) did not cause this accident. The driver behind you was looking for a way to pass you, and that is his/her problem. He/her did not have sufficient information to make the judgement to pass, but risked it anyway. This is the cause of the crash. The fact that the guy could not get past you safely is proof enough he was not being slowed down by you or your actions.

The same thing happens all over. Saw this on TV during a sports-car race this weekend. It was between two Ferrari's. The offender was doc'd 5 laps, and the other car was doc'd 2 laps for retaliating. Both of these drivers were basically out of the points for that race, and probably have blown their whole chance at this seasons championship podium spots. Just stupid.

Some people drive with thrust and slash manner, relying on underbraking. Others take a carefully considered line and push it for all its worth in a smooth manner. When your on the road you have to consider both. You were attempting to slow just enough to not have to stop. Stopping and restarting takes more time than coasting through a light. Your actions were aiding the forward progression of all traffic behind you. The other driver knew he was going to go into an uncontrolled situation passing you, and thought he was good enough and circumstances lucky enough for it to work out. It did not. Since this was not a life and death, or some high end on-track racing situation, it was just stupid on his part. Bear no guilt.

 

Hi Samiam,

I have to agree with PriusTouring07. A relative of mine was involved in a civil engineering study of a major downtown expressway system. They found that through-put maxed at 62 mph, in the study. Faster resulted in more accidents, but 55 mph (the speed limit) resulted in so many traffic jams (due to overloaded resource), and sudden stop situations, that the accident rate was higher as well. While the limit was not changed, the enforcement policy was, and the traffic on the road did improve. This was the situation for this road only. All other roads, and load demand are different of course.

And overall fuel consumption on this road was actually less at the higher than legal limit speed, consequently.

The exposure thing I do not buy. But faster reduces the resource consumption (feet of road lane-seconds), per driver goal achievement. Because other cars get out of the way faster. It depends on resource versus load how the road flows.

 

<div class='quotetop'>QUOTE(donee @ Jul 24 2007, 02:18 PM) [snapback]483887[/snapback]</div>

Engineers are always looking for throughput -- I'll also bet the study used models rather than actual crash data or even driving simulators. Having done (and published) some of the stats myself, regardless whether you control for speed homogeneity (relative speeds of target vehicle and surrounding traffic) or not, faster speeds have higher crash likelihoods and higher probability of serious injury and fatality. Its a simple matter of human reaction time and physics.

As for the autobahns, they are designed for fast traffic (and for landing airplanes during WW III, yes III). They are not safe because they are fast, they are relatively safe in spite of being fast, because of clear zones, center medians, center wire rope barriers, paving with high coefficients of surface friction and low stone polishing values, etc, etc, etc.

The faster you go the bigger the mess.

 

<div class='quotetop'>QUOTE(PriusTouring07 @ Jul 23 2007, 09:45 PM) [snapback]483910[/snapback]</div>

I think that as far as freeway/expressway driving is concerned, one should try and maintain the speed of the majority- ie: the flow of traffic. Usually that's going to be slightly above the posted speed limit. To drive slow enough to cause everyone around you to change lanes is antisocial and creates hostility, thus potential danger. Of course on the other side, driving too fast by weaving in and out of traffic is equally as dangerous.

Ever since I've become a Prius owner, I almost always maintain the posted speed and hug the far right side 'cruise' lane on long distance trips (which I take every weekend). But in the city, I "conservatively" speed alongside everyone else when on the freeway just to go with the flow... Not great for the MPGs, but better for my nerves and everyone around me..

 

<div class='quotetop'>QUOTE(local_host @ Jul 23 2007, 06:25 PM) [snapback]483787[/snapback]</div>

At present I have not hit 'reset' so the MPG display is the lifetime average over around 3200 miles as of today. That has comprised a 450 mile -each way trip to Savannah, a 340 each-way trip to the beach, a couple of days out and almost 2 months of daily 9 mile each-way commuting in city traffic. I've left it to show lifetime MPG for the time being to get an overall idea how it's doing for the first 2 or 3 months of mixed city, highway, short and long trips. At or around the first service I'll switch to tank by tank MPG, so will reset each time I fill up. The car, of course, resets the 'miles' figure with each fill up.

No special driving techniques at all. I generally don't accelerate or brake hard, try and anticipate traffic and road conditions ahead, drive close to speed limits, don't pulse and glide, have standard tire pressures and after the initial phase of ownership when I watched the energy screen a lot more than was probably safe to try and get good mileage, I now can tell from the feel of the car pretty much what it's doing, so just occasionally glance at the screen.

Of course the warm weather helps, but the poorest MPG I have got was close to 51 at a constant 70mph, where nothing much seemed to improve it. I've since found that at least on the flat, cruise control is very effective at eeking out slightly better fuel efficiency, so I suspect if I'd had it switched on, I'd have got slightly better.

In traffic, I found there are many occasions when a slightly light foot allows the car to freewheel or go into EV mode, where speed can be maintained easily over a mile or two with no fuel used, and where battery charge is replenished simply by letting the car slow down in anticipation of turns and intersections.

All that said, when I bought the Prius I was well aware that real-world mileage was not likely to be up to the EPA numbers, so would have taken your 48.5 as an excellent improvement over my previous vehicle which I greatly liked, but which was achieving more like 22. I've found the Prius very sensitive to road conditions and driving style, and sometimes apparently a bit variable in itself. On the trip to the beach last Saturday, I was frustrated to see it achieving little better than 50mpg on the display until I found a sweet spot at 62mph where that figure rose consistently above 55. Once I stopped, I wasn't able to find the sweet spot again for a while, but once I had, the number rose again.

Around town, I find the car has two different behaviors. In one, it will readily go into EV by feathering the throttle and then gently applying small acceleration, and in the other, no matter how hard I try, doing the same thing causes the engine to fire up. It is, as far as I can see, all about what 'mode' the car is in. Once warm, the engine needs to shut down for a few seconds (traffic lights for example) to enable it to go into EV and if it doesn't have the chance to do this, it won't without going above 35mph first.

Quirky behavior, but getting used to how the car 'feels' seems to help a lot.

 

<div class='quotetop'>QUOTE(GeoDosch @ Jul 23 2007, 06:06 PM) [snapback]483806[/snapback]</div>

I agree I'm a different driver as well. I've never driven really sporty cars, however, the cars I have had I drive fairly fast -- usually doing 80-90 MPH up I-95. I would also get upset when people do stupid things on the road, merging with no turn signal, blocking the left lane, etc. While I still shake my head in disgust when I see people doing those things, I'm not as upset about it because I'm only doing 10 MPH over the speed limit, at most, in the the Prius.

What "upsets" me now is when a line of traffic screws up my coast down a long hill and I'm missing energy soaking potential!!

 

I'd guess that changing lanes in and of itself, is not a problem... but ANGRY lane changing is. (And many a driver, being 'thwarted' by a slower car up front, pass in anger or frustration.)

 

<div class='quotetop'>QUOTE(ChristoB @ Jul 24 2007, 09:23 AM) [snapback]484106[/snapback]</div>

I will admit I'm one of those people who is angry when on the interstate you have a slow car riding in the left lane, blocking the flow of traffic, for like miles, and refuses to move over. As long as they are "passing" traffic in the right lanes, then I personally don't have a problem with it even if they're not going as fast as I'd like them to go -- it is designated a passing lane and they are passing.

 

Hi Friends,

I rarely Post but ALWAYS enjoy reading...

I commute 150 miles each workday on I-95 from Delaware to Baltimore and around the Baltimore beltway (I-695). I drive in the AM, always at 65MPH. My wife drives in the evening at 69-7- MPH (sigh).

We generally average 53-54 MPG, and we are using None of the hypermiling tricks... the car (and we) are just happy.

I do agree with the other posters... if MPG readouts were put in every car, the feedback would change behavior! I drive much more calmly now (and thank God for XM radio)

 

Texas has an 80 MPH speed limit on a 400+ mile section of I-10 between El Paso and San Antonio, they claim about 85% of drivers were averaging 76-79 MHP anyway, and that raising the speed limit actually reduced accidents (possible theory of moving people along the road faster leaves less opportunity for an accident? Also, maybe the higher speed increases how alert the driver is?). I've actually driven on this stretch in the Prius, dropping the average to around 50-52 MPG. Truckers are still limited to 70 MPH and the night speed is 65 MPH.

 

<div class='quotetop'>QUOTE(PriusTouring07 @ Jul 23 2007, 10:45 PM) [snapback]483910[/snapback]</div>

You probably meant 'reckless' driving?

I may not fully understand you daredevil types but In my neck of the woods 'wreckless' driving is a GOOD thing