Route conundrum...

[XYZ]

Originally Posted by razor02097

The short route is 2.1 miles. Average speed over the short route in a 15 day spreadsheet record is 19.6MPH @ 6 minutes 25 seconds. This was calculated by taking the average of the speeds and times over the 15 day period. This route includes 5 stop lights that are poorly timed, a small ascending grade and a large hill. I can time the lights but it takes a lot of throttle which is inefficient.

The long route is 5.7 miles. The average speed over the long route is 41.6MPH @ 8 minutes 13 seconds. I only have 3 data points so far (3 days). This route has only 1 stop light. There is a small descending grade initially then it flattens out the rest of the way.


I can keep a much higher average speed here but it takes about 2 minutes longer and I have to travel 3.6 miles further. It might not sound like a lot but it is more than two and a half times the distance of the short route.

There is another factor to consider. Since this is such a short distance your car may not be coming up to full operating temperature. In that situation it consumes more fuel due to fast idle, etc. The long route might allow the car to warm up more since it takes longer.

I wouldn't be surprised to find there is no advantage to either route. You might want to use the hill you mentioned by taking that route in one direction only, to give you a downhill advantage. The shorter route is fewer miles traveled, but the longer route may yield better MPG. Sometimes you just can't win...

[razor02097]

Originally Posted by XYZ

There is another factor to consider. Since this is such a short distance your car may not be coming up to full operating temperature. In that situation it consumes more fuel due to fast idle, etc. The long route might allow the car to warm up more since it takes longer.

I wouldn't be surprised to find there is no advantage to either route. You might want to use the hill you mentioned by taking that route in one direction only, to give you a downhill advantage. The shorter route is fewer miles traveled, but the longer route may yield better MPG. Sometimes you just can't win...

The vehicle would be at operating temp. Maybe I forgot to mention the commute home involves about 9 miles of freeway travel before I get to the point where I could take the 2 ways.

[XYZ]

Originally Posted by razor02097

The vehicle would be at operating temp. Maybe I forgot to mention the commute home involves about 9 miles of freeway travel before I get to the point where I could take the 2 ways.

Funny how we can forget to mention everything that might be relevant to the situation...

[razor02097]

Originally Posted by XYZ

Funny how we can forget to mention everything that might be relevant to the situation...

I was trying to be polite. It was mentioned in the first post.

Originally Posted by razor02097

I'm new to eco driving... I hope someone can advise me. I drive pretty much the same route every day. There are many ways I can take to bypass traffic but only 2 ways I can get home from the freeway. One route is longer but doesn't have any traffic lights or hills. The other route is shorter has 4 extra lights (which are horridly timed!), a slight uphill grade and a rather large hill.

It might be an easy question but the shorter route is actually 3.5 miles shorter...If I get stuck at every light (which happens about 50% of the time) both routes take about the same time to complete. I'm hoping there is a way to take this in to account. I don't have anything to tell me instant MPG.


My question is how can I figure out if taking the long way is actually worth it or not?

[XYZ]

Originally Posted by razor02097

I was trying to be polite. It was mentioned in the first post.

No, apparently you mentioned driving on a freeway in a cursory way, but you never mentioned 9 miles or any distance traveled on it. Maybe you thought you mentioned that, but you didn't.

Being polite may be nice, but it solves nothing. Providing all relevant information in an accurate way is more useful to solving a problem.

[slowmover]

Originally Posted by christofoo

I've put a lot of thought into this and I disagree on the economic bit. At least - in the context of the cars that I drive.

My Corolla in the 220k neighborhood:
$0.08 per mile repairs + maintenance over the last 33k
45MPG @ $3.6/gallon = $0.08 per mile (28MPG = $0.13/mile)

(I'm pretty sure the wife's Civic now in the 150k neighborhood has been significantly lower than that in repair $ per mile for the last 50k, but I haven't actually tracked it.)

(Razor never said it was about money. For all we know he wants to minimize CO2.)

Rhetorically,

Does this include all repairs and maintenance? Nothing broken or malfunctioning, correct? All up-to-date according to manufacturer service schedule?

Most folks will dial back on these expenses, reasoning that the vehicle is nearing end-of-service (for their purposes). The problem is that some will trade the vehicle when the carpet gets dirty and others not until both the trans and engine fail simultaneously.

The only fair comparison (between vehicles) about "economic costs" is in keeping the thing as near-to-new as possible. And the numerical comparisons are in maintenance/repairs on a cpm basis.

Those who have a stable of old cars have to run the numbers together for all of them. And still account for, or justify, delayed maintenance or repairs.

CPM calcs are either on the money or not. What I have spent can be considerably different than what I should have spent to meet the same criterion.

The longer route can be the better choice by a factor. The details that make it so are what need investigating.

.

[ciderbarrel]

Originally Posted by Gealii

I paid $70 for my ultragauge and have already seen a full ROI.

I second this. I am on my first tank of REAL eco driving in my Mustang GT (4.6 V8). I know that I'm only half way through my 1st tank but comparing it to previous tanks I have gone from 4.90g/100m (20.4 mpg) to 4.18g/100m (23.9 mpg). My last 10 tanks going back to early August were 20.8, 20, 20.4, 19.3, 20.6, 20.8, 20.3, 22.7, 21, 22.3. I think I'm off to a good start in below 40 degree temps on winter gas.

I'm driving the mostly same route as before because I'm an unemployed full-time student living on student loans. My only driving is to the Safeway and to my GFs place.

All I did was take out the CAI and re-installed the stock airbox with my ultraguage and play "beat the number" every time I drive. The hills are steep enough that I can coast in neutral for a quarter mile (or more) on local roads and highway. On the local roads, shifts at 2k with a skip from 3rd to 5th. Highway driving capped to 5 over the limit. No EOC at all, anywhere.

I drive about 5000 miles a year in the car (another 3000 on the motorcycle when the weather gets warm) and if I keep this up, I will save about 36 gallons a year (245.0 - 209) and at current prices that is about a $115.