When the price of oil hit $50 per barrel for the first time, the nation began to finally experience so-called “sticker shock” at gas pumps. And while spiking gas prices meant tough times for a lot of people, there was an undeniably positive effect.

In our country, when truck commercials pushed for bigger and better, tougher and stronger, we needed a shock. People began to drive a bit less and buy fewer SUVs, but for the most part, nothing changed.

Then the unthinkable happened: $100 per barrel. People with big cars saw their money taking them meters instead of miles, and found themselves spending whole paychecks at the pumps.

However, necessity is the mother of invention, and Americans needed transportation that they could afford. We pushed the government for better public transportation and, more importantly, the people responded by pushing these systems to capacity.

Drivers throughout the country sold back their gas-guzzlers, and car manufacturers responded to the almighty buck by changing their stocks, replacing big trucks with small sedans, prioritizing MPG over torque and pushing to be the most fuel-efficient.

People began to walk or ride their bikes the few blocks they were traveling, and workers prioritized finding jobs closer to their homes.

The twin problems of a petroleum “shortage” and the damage of greenhouse gases dovetailed together, convincing even the skeptical that gas is not the future — if for no reason other than it was too expensive.

But now, a mixed blessing has come, as the cost of petroleum has plummeted to the lowest we’ve seen in years, somewhere between $60 and $65 per barrel.

The small but necessary steps that Americans took as a result of the price shocks were a step that could be forgotten with the recent dip in oil prices. It is too tempting to resort to our old ways now that we can once again afford to.

Gas prices, though, should be the least important indicator of how much we should burn. Though many lament that we’re “running out of oil,” the question is not where our energy comes from but where it goes after we burn it.

To begin using petroleum again in the same quantities, or to simply point to something like natural gas as the answer, does not solve the key structural problem of our energy needs. Natural gas, after all, is just another fossil fuel and only postpones one problem while hiding another.

The European model is an interesting case study. While European governments have historically taxed gasoline much more than the U.S., the people have — successfully — lobbied for an excellent train system, widespread public transportation, and attracted car companies to send their fuel-efficient models.

Particularly with the results of Tuesday’s election, we must continue on the path that we began with the spike in fuel prices. Every politician has spoken about expanding public transportation and now that mandate is more important than ever.

This was a hard road and we learned important lessons. If we forget them now, we may not have the time to learn them again.