In 1968, a German mathematician named Dietrich Brace was working on traffic modeling when he realized

that in some cases, adding a new road or additional lane to a congested street or highway

can actually increase the amount of congestion on that street or highway. This is somewhat

counterintuitive because lanes and additional roads are generally added to reduce congestion,

to increase the number of available channels leading between endpoints.

But in his modeling, he found that this wasn't always the case.

There's an element here of what in economics is called Jevin's Paradox,

which says at times, if you increase the efficiency

with which a resource is used, whether through technological innovation or through some kind of

government policy, this can counterintuitively lead to more consumption of that resource,

because in its new efficient state, it's even more useful, which can then

increase demand. This is a perennial concern when it comes to electricity and fuel usage,

because as we increase the energy efficiency of cars and appliances, there's a chance

folks will end up using more energy instead of less, they'll drive more or buy more appliances or use the appliances they have at higher power levels.

Fuel is cheap, electricity is cheap, so why not use more of it?

The best of intentions then can lead to the opposite intended outcomes, not because pursuing efficiency is bad, but because efficiency can sometimes lead to higher demand.

The same is sometimes true on roads, it would seem.

If another lane is added to a busy highway, more people may decide to use that highway, even when previously they might have opted

for surface streets, or to take some other mode of transportation, because the highway was known

for its horrible traffic, but now has this additional lane, and that same decision to take the highway

by many people can lead to more traffic than before, despite the additional lane, or rather because

of it.

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