The UK government is currently flirting with a ghost from 1973. Facing a squeeze on oil supplies, the proposed "contingency plan" involves forcing drivers to slow down to 64 mph (103 km/h). The logic is as thin as the paper it’s printed on: cars use less fuel at lower speeds, therefore, a national mandate will magically balance the energy books.
It won't. It is a performative gesture designed to make a bureaucracy look busy while it fails to address the structural decay of energy security.
I have spent two decades advising logistics firms and energy conglomerates. I have seen what happens when you try to optimize a complex system by turning a single, blunt dial. It doesn't lead to efficiency; it leads to systemic friction, increased costs, and a massive transfer of wealth from the productive economy to the state's enforcement apparatus. If you want to "curb oil demand," stop treating the British motorist like a lab rat and start looking at the grid.
The Aerodynamic Fallacy
The central argument for lower speed limits rests on a simple physics equation. Drag increases with the square of speed.
$$F_d = \frac{1}{2} \rho v^2 C_d A$$
In a vacuum—or a high school physics textbook—dropping from 70 mph to 60 mph looks like a 20% win for efficiency. But the UK economy does not exist in a vacuum. It exists in a world of "just-in-time" supply chains and human behavior.
When you artificially cap the speed of the primary transport network, you don't just save fuel. You extend the duty cycle of every commercial vehicle on the road. A delivery truck that could previously complete five rotations in a shift now completes four. To meet the same demand, the company must put a fifth truck on the road.
Congratulations: You’ve just increased the total number of engines running, the total idling time in the resulting congestion, and the total carbon footprint of the fleet. The "savings" at the tailpipe of one car are vaporized by the systemic inefficiency of the entire network.
The Congestion Paradox
The "experts" pushing these limits assume that traffic flows like water through a smooth pipe. It doesn't. It flows like a granular material.
Lowering speed limits on motorways often triggers what traffic engineers call "phantom traffic jams." By narrowing the delta between the fastest and slowest vehicles, you create dense "platoons." These packs of cars are hypersensitive to braking. One driver taps their brakes at 60 mph, and three miles back, traffic comes to a dead stop.
Stop-and-go traffic is the single most inefficient way to burn hydrocarbons. An internal combustion engine is at its most efficient when it maintains a steady state at moderate-to-high RPMs in its top gear. Forcing a nation into a cycle of braking and accelerating because the motorway has become a high-speed parking lot is an environmental disaster disguised as a conservation effort.
The Real Oil Hog: It Isn’t Your Commute
If the government actually cared about oil demand, they wouldn't be obsessing over whether a Ford Focus is doing 70 or 60. They would be looking at the industrial heat and chemical feedstock sectors that represent the actual "unyielding" demand.
We have a bizarre obsession with personal mobility because it is easy to tax and easy to police. But the heavy lifting of oil consumption happens in the background.
- Petrochemicals: Everything in your house is made of oil.
- Aviation and Shipping: There is no "speed limit" for a container ship that doesn't involve breaking the global economy.
- Agricultural Runoff: The Haber-Bosch process, which keeps four billion people alive, is an energy sink.
Targeting the motorist is a "lazy consensus" move. It’s the policy equivalent of skipping dessert to lose weight while still drinking a gallon of soda a day. It feels like a sacrifice, but the scale is wrong.
The Hidden Cost of Time
Economists often treat time as a "soft" variable. It isn't. Time is the ultimate finite resource.
If you add 10 minutes to the daily commute of 30 million people, you are removing 5 million hours of human productivity from the economy every single day. At a modest valuation of £20 per hour, that is a £100 million daily tax on the British public.
Where does that value go? It doesn't go into a green energy fund. It simply vanishes. It is a deadweight loss.
When you hear a politician say, "It’s only a small delay for a big saving," they are lying. They are counting the pennies in fuel savings while ignoring the billions in lost economic output. They are forcing you to pay for their inability to secure long-term energy contracts or build nuclear power plants.
The "Contingency" Trap
These plans are labeled as "contingency," which is a euphemism for "we have no plan B."
The UK’s energy strategy for the last thirty years has been a series of panicked reactions. We closed coal plants without a bridge to baseload renewables. We neglected North Sea investment while pretending we could transition to an all-electric fleet by Tuesday.
Now, when the reality of global supply chains hits, the only tool left in the box is "stop the citizens from moving." It is the signature move of a declining power: if you can’t provide the energy your people need, tell them they shouldn't want it in the first place.
The Better Way (That They Won't Do)
If we were serious about curbing oil demand without destroying the economy, we would stop tinkering with the speedometer and start tinkering with the infrastructure.
- Variable Speed Limits for Flow, Not Restriction: Use existing Smart Motorway tech to keep traffic moving at the optimum speed for density, not a flat 64 mph. Sometimes that’s 50; sometimes it’s 80.
- Tax the Idle, Not the Move: Congestion pricing that actually works, targeting the areas where engines sit at 0 mph while burning fuel.
- Deregulate Small-Scale Nuclear: The only way to lower oil demand in the long term is to make electricity so cheap and abundant that using oil for heat or short-range transport becomes an economic absurdity.
The Truth About Compliance
Finally, let’s talk about reality. Speed limits only work if people follow them.
When you set a limit that the public perceives as arbitrary, cynical, or scientifically illiterate, you don't get compliance. You get resentment. You get a nation of drivers staring at their speedometers instead of the road, increasing the rate of accidents. You get an uptick in "aggressive" driving as people try to claw back the time the state has stolen from them.
I have seen this movie before. In the 1970s, the US implemented a national 55 mph speed limit. It was widely ignored, barely moved the needle on oil imports, and was eventually scrapped because it was a bureaucratic nightmare.
We are about to repeat the mistake because it’s easier to pass a law than it is to build an energy grid.
Stop asking how slow we need to go to save a gallon of petrol. Start asking why the fifth-largest economy in the world is so fragile that it has to cannibalize its own mobility to keep the lights on.
The speed limit isn't the problem. The lack of ambition is.
Put your foot down.
