Reminds me of an interesting site[1] I came across a while ago, in which the guy argues very convincingly that traffic jams occur as waves, which are started when even a single car does something to cause the car behind them to slow down (avoiding something, stopping to merge, etc). If it's non-trivial, then that will begin a chain reaction - a wave propagating through a medium of cars. The severity of that effect is directly proportional to the density of the medium/traffic.
Given that perspective, metering lights to reduce density seem like exactly the right solution.