There is a paradox in the world of building highways.  A reasonable person might observe a congested four lane road and believe that doubling the size of the road to eight lanes would decrease traffic congestion.  But the reality is quite different and has been observed in cities around the world for fifty years.  If you build a bigger road from point A to point B, the traffic congestion will remain about the same as before or worse.

Economists call this effect “induced demand” which asserts that increasing the supply of something (like a road) makes people want the thing even more.   Interestingly, the opposite of this profound truth is also true which is why major global cities are discouraging driving downtown during peak hours with increased tolls (“congestion pricing”).  Other cities like Paris and San Francisco are removing trafffic lanes and the amount of traffic declines with the reduced capacity.

Politicians claim that building more roads will reduce congestion.  Their supporters cheer and vote for more roads, but the stubborn truth remains that more roads will not ease congestion. 

Because the proposition (more roads will reduce congestion) sounds plausible, many people believe it to be true and vote for their politician who will cure their daily commute.

With agricultural irrigation, a related phenomena occurs.  Since water supplies are often shrinking while demand increases, farmers make up the difference by implementing increasingly efficient irrigation systems.  This game of reducing water quotas matched with increasing irrigation efficiency has been going on for several decades. 

Rather than reduced water quotas leading to reduced agriculture in drought-prone regions, farmers keep figuring out how to do more with less.  As they become more efficient with their water use, farmers then expand by planting more water-intensive crops. 

Even toilets in urban areas suffer the same problem.  When city officials change building codes to require “low flow” or 1 gallon per flush toilets, the reduced water demand is then matched by more people moving into the area.