NJ.com blogger Paul Mulshine recently posted an interesting review of dubious claims that a 55-mph speed limit improves overall fuel efficiency.  Mulshine provides a link to a variety of official sources, both domestic and international, that debase the myth of a single fuel efficient speed limit, especially one set at 55-mph.  “Every car I own gets better mileage at 70 mph than the typical SUV gets at 55,” remarked Mulshine. And while that may be true, it’s also worth noting that most modern passenger cars (and even SUVs) have evolved beyond the old carburated engines of yesteryear, and can achieve their highest fuel efficiencies at speeds above 55-mph anyway.