Vroom vroom

As societies, we should redefine our constraints on speed limits.

When I drive a car over the country, I'm bound by laws that restrict how fast I can drive. This makes sense, however I think we should redefine this to be a limit on momentum rather than speed. (I'm using the word speed here rather than velocity, but they're fairly interchangeable in the sense I intend).

A large lorry, weighing several tonnes, is restricted to the same speed as a small car. This doesn't make much sense since the energy required to propel a large lorry is much greater than a small car, and the energy exerted on the world by the lorry is, similarly, much greater than the car.

Where did the idea that speed was the factor by which we should measure vehicular movements come from? I imagine that in the early 1900s there was significant fear over the new mechanical vehicles that were becoming popular at the time. I don't know when these cars were fitted with speedometers, but was it simply a case of choosing the simplest calculator of danger (e.g. distance divided by time) rather than the more complex, but more accurate measure in terms of potential danger - the measure of linear momentum?

It makes sense to equate speed with danger, but there is a more complex factor, which is the mass of the vehicle involved. We are not oblivious to this so how did it get ignored even to the current day?

If I had the time, I would like to lobby for a change to the law. Every vehicle should be fitted with a momemtumometer instead of a speedometer. This new meter would measure the mass (or weight in real terms) and multiply this by the speed, resulting in a number that was much more related to the potential danger of driving at speed.

Apart from the benefits to road safety (lorries should drive slowly if carrying a large load - it's just obvious!), the benefits should carry over into environmental benefits. For example, if the government created multiple speed limits based on the momentum rating of the vehicle, then it would become beneficial for drivers who wanted to move quickly from A to B, to drive a light-weight car. This would transform into a reduction in nasty emissions over time (the assumption I make here is that, overall, these drivers wouldn't be able to drive at the top speeds all the time and would therefore reduce their carbon emissions, based on numerous fuel-related assumptions).

I like this idea because it's practical - it would make a difference to the planet in terms of road safety and climate change. However, I like it more than that, because it highlights the assumptions we take on from previous generations that were based on a more limited understanding of the world.

Conservatism isn't good when it comes to the practical benefits that are out there! We should be able to think more objectively about these kinds of things.

I don't hold much hope of that happening though.