Things Almost Everyone Can Do Now

In response to the following email we are pleased to announce several new bumper stickers. Dear Folks,Last week I sent this letter out to a number of conservation organizations, and also to Yes! magazine. They asked me for a reference and I couldn’t find it, so I googled “55 speed limit mideast oil” and BINGO! … Read more

Driving 55 and Math

All you need to know.W = F X DWork (energy consumed) = Force (aerodynamic parasite drag) X Distance traveled.Aerodynamic parasite drag force increases as the Square of the increase in speed.From 55 mph to 80 mph the speed increase is 1.45. 1.45 squared is 2.11Over DOUBLE THE ENERGY USED!Conversely slowing from 80 to 55 (55/80 … Read more

Time Value vs. Speed

When evaluating the value of time vs speed we must first recognize that as concerns energy consumption, the optimum speed for cars is about 35-45 MPH. After this peak, efficiency falls off rapidly and a law of physics called “drag” states the power (energy) required is quadrupled when speed is doubled. This means the faster … Read more

Physics Behind Driving 55

The power required to overcome the aerodynamic drag is given by: Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same … Read more

Drive 55 – Save your Pocketbook and the Planet

SACRAMENTO, CA – Long before most of us knew what it meant, Tim Castleman was “going green.” He walked or rode a bike to get around — and when he had to drive, he saved gas.Boy, did he save.”I got the lead out of my right foot and turned it into gold,” said Castleman. “It’s … Read more

55 mph Speed Limit to Lower Greenhouse Gas Emissions in Washington State

Transportation causes almost half of Washington’s greenhouse gas emissions. Lowering the speed limit to 55 mph would cut vehicle emissions by at least 10%. According to the Governor’s Climate Action Team, most cars and light trucks on the road today reach optimum fuel efficiency between 45 and 55 mph. Driving slower also reduces the incidence … Read more

German Autobahns and Speed Limits

Sometimes people like to point out that there are no speed limits on German autobahns as part of their argument against speed limits here. The following excerpt from clears this up nicely: Don’t let the high speeds on German roads fool you into believing that there are no reduced speed zones. Usually, speeders will … Read more

Speed Limits: How Should They be Determined?

The primary purpose of our highway system is mobility, not safety. If it were the latter, we would set speed limits much lower. A 20 mph speed limit, with governors o­n all motor vehicles to prevent exceeding that speed, would certainly lower highway casualties. Of course, no o­ne would consider such a measure, Clearly, we … Read more

Case Study: VW Beetle 76 mpg

Hi, I thought this story should be of interest to you. I did drive 55 (52 to 53 true speed) to set this mileage record. I don’t recall passing anyone on the entire trip.Ernie RogersOver the Labor Day weekend, the TDI Club had it’s annual get-together called “TDI Fest.” The club has a large percentage … Read more

Letter to DOE Secretary Steven Chu

Dr. Chu:In synch with the new vehicle fuel efficiency standards, I strongly recommend that a national maximum speed limit of about 60 mph be implemented ASAP for ALL vehicles. Such a limit would yield IMMEDIATE benefits with EXISTING vehicles including:Greater fuel efficiencyReduced emissionsImproved highway safetyFuture vehicle technologies and designs would be more easily facilitated, simplified … Read more