Fuel Economy Update for August - 2014 Mazda Mazda3 S Long-Term Road Test
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Fuel Economy Update for August - 2014 Mazda Mazda3 S Long-Term Road Test
Edmunds reports the fuel economy for the month of August on its long-term 2014 Mazda 3 S Grand Touring. The Edmunds editors averaged 28.1 mpg for the month.
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Using the amazing powers of analysis provided me by long ago obtaining a Bachelor of Science in systems science and mathematics, I can tell that you might be hitting the EPA "city"/"highway" figures exactly but have an 80/20 split instead of the 55/45 the EPA assumes; or you might be hitting the 55/45 split exactly but getting 2.5 mpg lower than the EPA in each type of driving for various reasons: you experience more congestion than the EPA assumes, you run the A/C on a higher duty cycle than the EPA assumes, your fuel has a higher percentage of ethanol for lower volatility, et al. Reality is likely a combination of factors in between; the city/highway deficit is probably not identical, e. g. Actually, I can also hypothesize that the EPA ratings were rounded up from 26.5+delta and 36.5+delta (because otherwise the combined mpg would more likely round up to 32, not down to 31). So your split could be 76/24 or you could have only a 2 mpg deficit vs. the EPA. Based on these numbers, I wouldn't say the EPA is necessarily hosed. My own experience with an i Touring 5-door automatic during the last 3 months (not including the 600 mi break-in period) is 30-33 daily driving vs 30 EPA and 39-41 long-distance vs 40 EPA (mostly blue highways; based on trip computer vs. actual, I estimate I may get up to 44 mpg on interstate-grade highways), 32.7 overall (which rounds to the EPA's combined 33 exactly, although my proportion of "city" driving is much higher than 55% so far, closer to 75%).
@bc1960: It's also possible-- even likely-- that the Edmunds team is harder on the throttle than EPA testing prescribes.
Oh, certainly, but occasionally I've been trying to point out that among other things the EPA's new emphasis on the combined figure is more misleading than the prior sticker since you introduce not only uncertainties in the mileage tests themselves, but assume a specific split in driving milieu; so not matching the EPA combined doesn't necessarily mean you're actually getting worse mileage than the EPA predicts. That point was probably lost amidst the rambling. In multi-car families particularly I expect that at least one vehicle is probably driven far more miles as a local commuter than a long-distance traveler. Once I take my vacation in a few weeks I expect my own highway mileage to improve along with the overall.