JL: Heading west on Wilshire, I'm sticking to the right lane, which is the least crowded. The risk, however, is that one of the city buses up ahead might stop. So I keep one eye on my side mirror in case I need to hop over a lane, continually monitoring the bus for indications of a stop while also looking two or three lights ahead trying (futilely) to time them. This is relaxing.
JC: I decide not to cheat when I remember one fun rule of fuel-efficiency: the wider open the throttle, the less the pumping losses. The M3 has eight throttles, so in my twisted mind, the benefit of a heavy right foot will be eight times as big. I'll keep the revs under 2000 rpm and do all accelerating in the highest possible gear with the gas pedal on the floor, thank you. And I'll keep my speed below 55 mph once I get on the highway. No other nerdy tricks needed!
PL: This ScanGauge thing is genius, at least for hypermiling devotees. I'm not sure how much it's actually teaching me, but watching the mpg numbers rise and fall is somewhat entertaining. 33.4! 44.1! 52.6! (Cue violin crescendo.) 9999!!! Joy is coasting down a hill.
JL: On a nice downhill, I see an indicated 99 mpg (evidently the max readout on the Yukon's instant-fuel-economy gauge). Hooray! Immediately, the traffic light at the bottom turns yellow. I could slam on the brakes and stop a few hundred feet short of the intersection (to preserve potential energy), but with a line of cars behind me, that seems unwise. Instead, I slow to a crawl, hoping the light will change, which it does - just as I stop and key off the engine.
PL: Onto the 405 North. I'm expecting major traffic, and I figure that my local knowledge will come in handy here. (Counterintuitively, the right lanes tend to move faster when it's congested going over the hill.) But there's no congestion to speak of, and the only slowdown is being caused by . . . me. I'm trying to keep my mileage in the high teens, and the only way I can do it is by dawdling along at 45 mph. Predictably, cars stack up behind me. Jeez, now I'm seeing 12.8 mpg at 42 mph. Inclines really, really suck.
JL: Finally, I enter the 405 North - average mileage through the city: 13.4 mpg. Oh, my.