Friday, July 03, 2009

Difficult Left Turns

Guest blog post by ChipSeal

You are making a right turn from a side street onto a very busy, 40 mph speed limit road (with 50 more common). The road has three lanes of dense traffic in each direction, and about a quarter mile up you need to turn left.

Oh, and about a quarter mile up this busy road is a freeway service road interchange. There are occasional gaps in the traffic but always a chance of a right turn on yield coming off the freeway.

How do you approach such a scenario?

Doohickie has asked me to give my advice on the above question.

Here is a Google map of the area. But not being there, I don't see what your concern is with the freeway service road. Setting that aside, here goes:

My strategy would be to wait for a gap large enough to to turn directly to the left lane when I entered the street. The key to left turns on high-speed busy roads is to merge early. Way early!

I suppose I would also turn into the center lane and then merge left as soon as I could if there were no gaps big enough to reach the left lane at the start.

I also do not wait for a gap that is so long I will prevent a motorist from braking. I am not going to accelerate to their speed, so no matter how big the traffic gap, they will have to slow down or merge. I just look for a gap big enough that they have the space they need to slow down for me.

Riding in the left-most lane will be confusing to many motorists, but they will merge right to overtake you. It is perfectly within the law to take the left lane when you are preparing to turn left. On high-speed streets, you have to get left early, so early that until you get used to doing it, it seems insanely early. If you wait, you can get trapped in the right lanes and be unable to merge. Merging across early is far less stressful.

While it doesn't show an early merge across multiple lanes, this video does demonstrate merging early and shows the reaction of nearby traffic. And besides, who doesn't like watching Keri ride her bike?

I have found another good film, but is is not as easy on the eyes. Preparing for left turns is demonstrated starting at 1:50 and then another one at 7:40.

Photos by Fred Oswald © Copyright 2005-2008 LAB Reform. Material may be copied with attribution.


ChipSeal said...

Kerri Caffrey, from blog has made this helpful comment on the parallel posting at my blog.

She said, "General advice: Remember, when you are in a lane, traffic is flowing around you with increasing density in the other lane(s). That's why it's so important to merge early in a gap. I want the platoon to see me in the place I'm going to be as they approach. Especially on a high speed road. It's pretty easy to negotiate a merge though 30mph traffic. But I've had a dozen cars blow past my extended left arm as I was trying to merge on a 50mph road.

Another tip. If you miscalculate and get blocked by a platoon, don't panic. You can always do a jug-handle or box turn.

"Platoon" is a group of automobiles between gaps. They are often formed by queuing up at light signals.

Steve A said...

I think Doohickie's turn is somewhat similar to my "FS1" turn, as posted at: except my left turn lacks a traffic light.

If you click on the map in the post, it's easier to see. It's roughly a quarter mile from Keller Hicks to Pearl along Denton Highway.

In all cases, the southbound traffic is light in the photos because the signal light creates giant gaps in the traffic that are perfect for cyclists wanting to go places.

Similarly, there are very sweet gaps in the northbound traffic, though not at the same times.

It all looks like chaos to a casual observer, but it's not.

Lovely Bicycle! said...

Um. Wow. This route puts my commuting anxieties to shame!...

Doohickie said...

I would have agreed a year ago, Lovely. With more time out on the road comes better technique and more confidence.

Steve A said...

It's a lot simpler, and, dare I say it, MORE FUN, than it looks.

BOOKMARK THIS POST - and compare it with a Doohickie post six months from now...

Doohickie said...

...or six months ago, when I was just learning of vehicular cycling.

Lovely Bicycle! said...

Well, I guess this will give me something to strive towards. For now, I am still in the "trying not to cry when feeling a car whiz by just 2 inches from my left arm" phase. Do your lady friends cycle on these roads with you?

Doohickie said...

My wife doesn't ride at all due to several ailments.

Actually, cars will give you more room if you ride out in the lane further. Try riding in the left tire track of the right lane someday; you'll be amazed at the respect you get!

popeye cahn said...

Hmmm I still enjoy the stone zone plus the cagers here accept them and understand the concept.