City technique, not seen this mentioned...
 

Hi folks,

So I had errands to run yesterday and I was doing my "usual" trick, which is usually automatic, but caught myself consciously thinking about it... and though it seems somewhat like common sense to me because I've been doing it for years... I realised I don't remember seeing it mentioned on any of the F-E sites I've been to...

When you're driving in a typical North American city, the roads are on a grid pattern, this means that often you'll find yourself driving say 5 blocks N/S and 4 blocks E/W to get somewhere. Now if you have some familiarity with the city, you can usually modify your route to the best advantage for mpg by trying to follow the following rules.

From your starting point, set out in the direction that will require the least amount of left hand turns. (Should traffic be light and all the lights be with you) This will mean going clockwise around your route, there and back on different routes. Left hand turns usually involve waiting for oncoming traffic. Right hand turns don't.

If you do have to make a left hand turn at some point, try to take it at an opportune moment, i.e. if you're stopped at a light that you know will give an advance arrow, or the road happens to be clear when you come up to one of the lefts you could take.

Make the most of green lights, don't take right hand turns early if you've got the lights "with" you and can go straight through them without losing momentum and wasting fuel to braking.

If you get red lights, or are reading the road far ahead and traffic is moving very slow or stopped, turn right if possible. You have to slow down, so you may as well make the turn. You may have to do a "make up" left, but can try to spot opportunities to do that with no wait, and you may get a short wait, a good trade against a guaranteed 3-5 minutes idling, or 10 mins in bumper to bumper crawl.

In other words, try to spot the lucky breaks early and take them.

I think that's more or less it, when you know the city well you can also take into consideration current construction, busy intersections, school zones etc, that may have more bias on your route. Sometimes you're finding yourself making a lot of turns, but you're only slowing to 15 or so, instead of a dead stop, keeping moving instead of waiting at lights, and you cover the same distance. When you've got a few blocks to go, you can play the odds a bit, if it's too busy to take the left here, you've still got a few more blocks in hand to take a clear left if you see one.

Usually seems to work out that you get around the city pretty quick too, keeps your average speed higher. Oftentimes we'll just all take the easiest, no brainer route, like when only the main drags are plowed in winter, or when the brain is a bit too foggy to make the route adaptions. But when driving "turned on" to traffic conditions and taking turns instead of waits, you can save quite a bit of gas and time. I sometimes seem to stun the passengers with it a bit, first there's the "where are you going??" if you don't just go the well travelled (i.e. congested) route, and then also the "wow that was quick" factor as they realise you just got them across the city in 15 minutes instead of 25... legally.

regards,

Road Warrior

really nice explanation! i never thought about this before, i guess this should be posted somewhere thats under "driving technique"

UPS had a policy enacted last year in which left turns are significantly reduced in delivery routing of their trucks. The company announcement specifically mentioed the faster completion times and the reduced fuel comsumption.

3 rights don't make a wrong, they make a left! ;)

Was about to mention this one myself. I like it...I'd always avoided left turns myself, just because I don't like doing lefts.

When studying route theory (something I did for a long time in college), it was found that most people did not take the same route to a destination as they did from it when walking. Why this does not translate to driving is beyond me, but it's true. The significant thing about this is that routes are not reversible in most people's minds. In other words, they can often get lost when trying to just reverse their route.

That said, when driving, most people DO reverse their routes, and consequently end up making equal numbers of turns, making at least part of their route needlessly lengthy.

This suggestion of mapping out the least lefts is a good one. I have about 15 certain routes through my city that actually take advantage of timed greens to make turns. After reading this post, I figured out that 90% of these are specifically because they are left-turn friendly!

So I second this motion - it really is a good one.

i drive for a living and have been doing that technique for quite some time. i call it driving opportunistically.

that said, the method of driving used like anything else is on a case by case basis. certainly there are "routes" that there is ONE absolute way to travel, barring delays of course. for the others, simply knowing the traffic lights and paying attention dictates the direction travelled.

btw, do not forget that left turns are not evil. oftentimes that left green arrow comes before the staight on green light. KNOW where you are!

That just reminds me of a light in the neighboring town where the left turn timing is completely backwards. Solid green for opposing straight traffic, then it switches to the protected left turn signal. I can only guess it's somebody's idea of a joke.

There's a hosed up one like that in the town over from me as well. I hate it because you're never sure the traffic coming the other way is gonna stop until it does and everyone behind you lays on the horn.

Snax,

i did a short gig for my local city public works about 8 years ago. my dept was right next door to traffic control. anyhow, we used to bust their chops about fixing the FUBAR traffic signals in town.

SOMETIMES they listened and acted, other times, well...