Saturday, September 12, 2009

Hazards 2: Interchanges

I was having a Saturday-morning kaffeeklatsch conversation with some ex-pats from overseas (there are a bunch of them who live out in Maryland suburbia, who work with NASA, in the diplomatic corps, and for agencies, well, let's just say they don't talk about their work very much.) One of them recognized me as a regular cyclist, because he'd seen me often on our neighborhood streets (I was so pleased), and so I gently (honest!) steered the conversation towards cycle-commuting. One of the guys was from Holland, and of course he liked to cycle "back home", but he said the hills in Maryland were too much for him. Another of the guys (an antenna designer for NASA) said that at one time he lived just 9 miles from his work, and (so he said) he would have liked to bike but there was a big highway in the way and he couldn't figure out how to get across it.

I knew the highway he was referring to, and I cross it regularly. There is an overpass about every mile along its length, but the overpasses are secondary roads, legal to cycle on, but certainly intimidating for the inexperienced. The overpasses can be particularly intimidating, and I thought it might be interesting to throw out the method I use to cross them. (Here's a link to the excellent "Infrastructurist" blog that the image at right comes from.)

Let me say right up front that this is vehicular cycling, and I've come to the realization that it's just not for everyone. I think that VC requires a commitment (and, often as not, a little bit of militancy in that commitment) to the concept that bicycles-have-full-vehicular-rights. It also requires concentration, some athletic ability, and some developed cycling skills. With all these ingredients available, VC is not dangerous, but as I say, it's not for everyone. In the America of today, though, it is the way to become carless if you don't want to wait for the powers-that-be to develop infrastructure. (This is not to take anything away from the Urban Repair Squad.)

The skills required for this apparently obvious maneuver are three:
  • The ability to ride up a gentle incline (as are most interchanges) and maintain a speed, say, in excess of 10 mph;
  • The ability to "ride a line" in traffic, to ride right on a highway stripe and not swerve even when cars bypass at speed;
  • The ability to look back in both directions without leaving your line of travel;
I say "apparently obvious" because in essence all the cyclist does when crossing an interchange is go in a straight line. I've seen experienced cyclists (although not experienced in the vehicular sense) mess this one up, always trying to be next to the curb or shoulder, and crossing too many vehicular lanes in the process. The State of Maryland "rules of the road" booklet is a little ambiguous on the practice of bicycles and turning lanes. It says:
A bicycle should be operated as close to the right side of the road as practical and safe. However, cyclists are expected to use turn lanes.
It doesn't say, however, in this context how bicyclists are supposed to use them. (I've contacted MD-DOT and will post their clarifications here when and if I receive same.)

So, anyway. Back to the topic at hand, which is the interchange. A most common interchange that one would encounter here in Maryland is the classic "cloverleaf" which I've illustrated in an adjacent image.

I've analyzed the crossing of this interchange and find that it contains seven (!) zones that have to be traversed, and each zone requires a separate response. Each zone is unique, but some are similar to others. Take a look at the illustration.

Our intrepid vehicular cyclist is crossing from bottom to top. The primary road (say an expressway) is the horizontal main road. The secondary road (typically a road with a speed limit of less than 50 mph) is the one our cyclist is on. We'll assume the secondary road has a decent rideable shoulder. (This is not necessary, but most secondary roads of this character do in fact have this, so it's a reasonable assumption.)

So, let's descibe the seven steps of getting across a highway interchange. They are:
  1. In this zone the cyclist is riding the shoulder, looking over his left for oncoming traffic that may not see him;
  2. In this zone, the cyclist is "riding the line", on high alert for motorists overtaking, not being aware of him, and crossing in front of him from left to right;
  3. In this zone, the cyclist gets a brief mental rest (on the shoulder again) and looks to his right to assess oncoming traffic from the loop;
  4. In this zone, the cyclist is again "riding the line", on high alert particularly for motorists coming off the primary road overtaking, not being aware of him, and crossing in front of him from right to left. Since there are also cars on the left, this is probably the most intimidating section;
  5. Another brief rest. This is similar to zone 3, as the cyclist should be looking right and anticipating;
  6. In zone 6, the cyclist will either "ride the line" if there is bypassing traffic on the right, or, if the road right-behind is plenty clear, make an efficient crossing to the shoulder. (I say efficient because for obvious reasons this lane is no place to dally);
  7. The last zone, the cyclist has regained the shoulder and is on his way;
So. There you have it, a quite complicated way to get from point A to point B in a straight line. Most experienced vehicular cyclists might well regard this post as both obvious and trivial. But I put it up to make explicit what the requirements are for VC. Mind you, I think the rewards are commensurate, to be sure. Freedom is a wonderful thing.

5 comments:

trikebum said...

Hi Robert,
I like to think that I ride VC but I don't tink I woud be riding any line.
If I was riding that road I would just occupy the full curb lane which is legal in most juridictions where they say 'as close as practicable to the right'. Check out: http://www.youtube.com/watch?v=0B18Pwdnyb
Ride on...!

Mighk said...

Robert:

As both a cyclist with 40+ years of experience and a cycling instructor with about 15 years experience, I have to disagree with your contention that vehicular cycling requires athleticism and/or militancy.

I used to be a fast rider. These days I'm usually riding in the 12 - 15 mph range and I've found that my problems in traffic have _decreased_, not increased. My "militancy" has also decreased. I'm now far more relaxed on the roads than I was 10 years ago.

Operating under the assumption that you _belong_ on the roads and that you are entitled to full use of a lane does not have to result in a militant attitude. It can just as easily be supported by a matter-of-fact attitude.

Mighk said...

Robert:

As both a cyclist with 40+ years of experience and a cycling instructor with about 15 years experience, I have to disagree with your contention that vehicular cycling requires athleticism and/or militancy.

I used to be a fast rider. These days I'm usually riding in the 12 - 15 mph range and I've found that my problems in traffic have _decreased_, not increased. My "militancy" has also decreased. I'm now far more relaxed on the roads than I was 10 years ago.

Operating under the assumption that you _belong_ on the roads and that you are entitled to full use of a lane does not have to result in a militant attitude. It can just as easily be supported by a matter-of-fact attitude.

Robert Anderson said...

Mighk, There are a lot of cyclists out there for whom "12-15 mph" is close to the limits of their athletic ability. Your description of it as apparently diminished performance is telling, I think. I believe the ability to accelerate, ride with traffic, and be a competent vehicular cyclist does require athletic ability. Not at a professional or even a club level, but at the upper reaches for much of the population.

Keri said...

Robert,

As someone who frequently hauls a trailer, I can attest that speed does not matter. I often operate at single-digit speeds.

Mighk didn't say anything about diminished performance. He used to do club rides. Now he's hauling compost and ladders and such on a long-tail utility bike. His point was that letting go of the notion that one has to ride fast to ride on the road resulted in a higher quality experience.

I used to believe I had to ride at top speed and that one had to be athletic and militant, too. Years ago, when someone told me speed didn't matter, I didn't believe it. But I went out and experimented and I experienced the same thing Mighk described. It was very liberating!

Our many students who ride townies and other casual bicycles also have no problem driving their bikes on the road at low speeds. The perpetuation of the speed/athleticism myth has become an unwarranted barrier to practical cycling for a lot of people. It's as pernicious as fearmongering.

I also recommend using the full lane as trikebum suggests. Riding the line between lanes is a bad idea. It leaves you nowhere to go and causes more confusion and disruption than controlling the outside thru lane.