| It is a topic which has been fought ever since | | | | MPG once accelerated to 65 MPH. At 75, it was |
| implementation, and successfully, too, as there are | | | | down to 30 MPG. Assuming that car was a |
| currently no national speed limit guidelines. A | | | | perfect national average example it would be |
| federally-mandated speed limit was initially | | | | driving 11,900 miles, with 45% on the highway, |
| implemented in 1974 with the passage of the | | | | and 55% in the city. Gleaning the appropriate |
| National Maximum Speed Law. As a response to | | | | amount of miles for highway driving only, the |
| the 1973 oil embargo, it was an attempt to curb | | | | vehicle was driven 5,355 miles at high speeds. If |
| fuel consumption through the reduction of speed | | | | the driver kept the vehicle at its optimum speed |
| on all roads to 55 MPH or less. Fast-forward 13 | | | | of 55 MPH, they would have consumed 133.875 |
| years, and oil is no longer a scarce resource (at | | | | gallons, releasing 1,178.1 kilograms (2,597.175 |
| least at the pump). With fuel prices | | | | pounds or ~1.3 tons) of CO2. However, if the |
| (comparatively) low, and drivers clamoring for | | | | vehicle was consistently doing 75 MPH, the |
| higher speeds, the federal government passed | | | | consumption would be 178.5 gallons, releasing an |
| the Surface Transportation and Uniform | | | | additional 392.7 kilograms (865.725 pounds or ~0.4 |
| Relocation Assistance Act, allowing states to raise | | | | tons) of CO2. |
| rural speed limits to 65 MPH. Forty-one of them | | | | This may not seem like a big deal, but remember |
| did exactly that. Another eight years pass, and | | | | those national totals? Let's assume that every |
| President Clinton signs the National Highway | | | | registered vehicle drove at 75 MPH on the |
| Designation Act, proposing, among other things, | | | | highways, and that the percentage decrease in |
| the elimination of all national speed limits. States | | | | consumption was similar (75% of optimum) on all |
| were now free to raise speed limits on national | | | | vehicles (this is an under-exaggeration, as many |
| roads as they saw fit. | | | | vehicles with poor aerodynamics decrease much |
| This is where America's highway policies currently | | | | faster than the example Camry). Now, we will |
| reside. Most highways have posted speed limits of | | | | assume the national average of highway MPG is |
| 65 or 70 MPH, while actual vehicle travel rates | | | | 25 (deliberately overestimated, considering |
| may be 5-10 MPH higher. Speeds of 80 MPH are | | | | combined is only slightly over 17 MPG). Achieving |
| not uncommon to see in both rural and urban | | | | only 75% of this value in real-world driving |
| road conditions. Besides showing how much of a | | | | provides an actual highway average of 18.75 MPG. |
| rush Americans are often in, what problems does | | | | Now, this isn't taking into account the minimal |
| this create? Keeping in line with the company | | | | decrease in engine operation time (due to the |
| policies of 3P (People, Planet, Profit), let's begin | | | | faster speed). Such a value would likely pose as |
| with the human aspect. | | | | only a fraction of the additional usage, since the |
| Speed kills. This isn't a new and surprising phrase, | | | | consumption curve increases exponentially, not in |
| however, the area in which it is describing may | | | | a linear fashion. Regardless, such a mileage |
| be. According to a study published in the | | | | reduction equates to annual CO2 emissions in the |
| American Journal of Public Health in September, | | | | United States, simply as a result of driving 75 |
| 2009, the progressive elimination of national speed | | | | instead of 55 MPH, of 159,846,544,482.24 |
| limits has resulted in an estimated total of over | | | | kilograms (352,388,973,063.12 pounds or |
| 12,500 additional traffic accident deaths since | | | | ~176,194,486 tons). Astounding in its own right, |
| 1987. How could this be? Vehicles have | | | | more so when it is seen that it is 10% of total |
| undoubtedly become safer, yet people continue to | | | | consumer automobile emissions in the U.S.! |
| die in high-speed accidents. One could explain it | | | | Getting outside of the complicated math, that |
| away with the increase of automobiles on the | | | | value bears repeating. It is entirely possible (as |
| road, however, that does not explain these facts: | | | | shown above), that up to 10% of nationwide |
| In the year following the passage of the National | | | | passenger vehicle fuel-based CO2 emissions are |
| Maximum Speed Law, car crash mortality fell | | | | avoidable simply by slowing down! Of all climate |
| 16.4%. Additionally, following the elimination of set | | | | change policies in deliberation, this seems to be a |
| speed limits nationally, in states which did not | | | | "low-hanging fruit". Please understand, these values |
| change their speed rules, highway deaths fell again. | | | | are simply for presentation and educational |
| On the other side, crash fatalities following the | | | | purposes. While determined to the highest |
| Surface Transportation and Uniform Relocation | | | | accuracy, actual results may vary due to a |
| Assistance Act increased 9.1% in states which | | | | variety of factors. Nonetheless, the writer |
| changed their speed limits from 55 to 65 MPH. | | | | maintains its significance. |
| With the elimination of all national set speed limits | | | | So the first P, People, showed how lower highway |
| in 1995, urban highway deaths increased 4%. In | | | | speeds reduce the number of fatal accidents. The |
| addition to the over 12,000 deaths considered to | | | | second P, Planet, provided an environmental |
| be a direct result of higher speeds, the study | | | | rationale to driving slower. The final P, Profit, aims |
| found over 36,500 injuries as a result of those | | | | to provide a financial incentive to accomplish the |
| fatal crashes. A federal speed limit is likely to have | | | | same goal. |
| similar results today as it did in 1974, reducing | | | | At the time of writing, the current national |
| highway deaths by a comparable percentage. | | | | average for regular gasoline is $2.585. Using the |
| The second "P" highlights the Planet. In this case, | | | | values determined above, the national expenditure |
| the environmental impacts of high-speed highway | | | | of driving all those vehicles on the highways for |
| driving. According to the Bureau of Transportation | | | | 5,355 miles at 25 MPG is $140,864,767,324.97. |
| Statistics, in 2007, there were 254,403,082 | | | | However, at the adjusted value of 18.75 MPG, the |
| vehicles registered in the United States. On | | | | cost increases to $187,819,689,766.63. The cost |
| average, each vehicle was driven 11,900 miles | | | | savings potential nationally as a result of driving |
| annually, consuming approximately 1 gallon of fuel | | | | slower is an astronomical $46,954,922,441.66. Per |
| for every 17.2 miles traveled. This results in an | | | | vehicle, this results in an annual savings of $184.57. |
| annual consumption of 692 gallons per vehicle. | | | | That type of return resembles the recent tax |
| According to the EPA, a gallon of gasoline burned | | | | rebates, and yet this needed no public or private |
| in an engine produces 8.8 kilograms (19.4 pounds) | | | | expenditure! |
| of CO2. Using the previous statistics, each vehicle | | | | We hope this has been an informative look into |
| should produce 6,089.6 kilograms (13,424.8 pounds | | | | the true costs of high-speed highway driving. |
| or ~6.7 tons) of CO2 each year. Multiplied by the | | | | Summary of "3P"-based analysis on lower |
| total number of registered vehicles in the country, | | | | highway speeds: |
| and the results show that American driving habits | | | | People |
| culminate in the release of 1,549,060,366,298 | | | | Over 12,500 deaths could have been avoided |
| kilograms (1,707,655,248 tons) of CO2 annually. | | | | since 1987 |
| So what does this have to do with a Federal | | | | Over 36,500 injuries within fatal car accidents |
| speed limit? Higher speeds require more energy | | | | could have been avoided in same time period |
| to maintain, and the energy source in most | | | | Fatality rates increase following speed limit |
| vehicles is gasoline (or a petroleum product, | | | | increases |
| including diesel). A basic rule of thumb is that, once | | | | Fatality rates decrease in states with no speed |
| at highway speeds, the energy required to fight | | | | limit changes |
| aerodynamic drag increases exponentially. Put | | | | Planet |
| simply, if speed doubles, the energy required to | | | | MPG falls as speed exceeds 55 MPH |
| do so quadruples. For a vehicle doing 50 MPH in | | | | Potentially 10% of nationwide passenger vehicle |
| one run and 100 MPH in another, it will have | | | | fuel-based CO2 emissions a result of high-speed |
| burned twice the fuel in the latter test (4 times | | | | driving |
| higher consumption in half the time). According to | | | | Profit |
| research by Consumer Reports on a stock | | | | National cost savings through speed reductions on |
| Toyota Camry, the vehicle was consuming at a | | | | highways: $46,954,922,441.66 annually |
| rate of 40 MPG at 55 MPH, however, it fell to 35 | | | | Per vehicle cost savings: $184. |