Seeing green?

A friend posted this photo on facebook.

Shared-lane marking with green underlay

The placement of the shared-lane markings shown, centered in the lane, is good. The shared-lane marking is a standard treatment in the Manual on Uniform Traffic Control Devices (MUTCD), as is green paint for use in bike lanes. As of this writing, the green paint underlay of a shared-lane marking is in experimental status. Issues which might oppose it: the expense of the added paint; does it actually affect behavior; the “cry wolf” effect of use of green paint in increasing numbers of types of installations.

Traffic control devices — signs, signals and markings — are supposed to express a consistent symbolic language. In North America and in countries influenced by North American practice:

  • Rectangular signs with a white background are regulatory signs — that is, they indicate what the law requires. Examples are speed limit signs, no-parking signs, no turn on red signs.
  • Yellow, diamond-shaped signs are warning signs, indicating a potential hazard or the need for caution.
  • Green signs with white text are directional signs, or wayfinding signs. Examples are street-name signs, the signs preceding off-ramps on interstate highways and bike route signs.
  • And so on — blue background: emergency routes or services; brown background: parkland information; orange: construction zones.
  • Similarly for paint on the road, yellow is for a line or area which drivers are not supposed to cross; blue, for handicap parking; green, for use in bike lane conflict zones; white, for most other road markings.

Of all of the colors for road paint, green, being the newest, is the one least standardized, and there is a tendency to use it indiscriminately, — so road language becomes road slang, with inconsistent and changing meanings.

The experimental process leading to inclusion of new signs, symbols and markings in the MUTCD is intended to refine, and define, their use, and to forestall the confusion which results from indiscriminate use.

This process has sometimes been criticized for being too cumbersome, but on the other hand, consistency matters!

7 Responses to Seeing green?

  1. One other item – if not properly formulated and applied, large paint areas on the pavement can present a fall hazard to cyclists when wet. I have fallen on such. Some of those paints are no better than ice when they are wet.

  2. Two issues. One as Steve mentions. If one is adding a surface treatment, has it been tested properly in dry and wet? I’ve recently discovered the wonders of those narrow tar patch treatments that the highway departments use to patch roads. They can be lethal to a motorcyclist. Have not crashed on one yet but last week got the 600 lb BMW seriously squirrelly on some linear patches at 60 mph. Leaving surface treatments to a car based culture can be interesting.

    Two, standardization. What happens on streets that don’t get this treatment? Will we get different behavior with and without the green paint?

  3. Luckily, Khal, motorists are well trained not to run into stuff right in front of them regardless of pavement nonsense. Well, unless that stuff falls down right in front of them unexpectedly…

  4. No kidding, Steve….there are certain advantages you have over me, you being a Jaguar aficionado.

  5. Those look very similar to the sharrows at intersections in The Wiggle of San Francisco, where they serve both positioning and routefinding functions. They’re placed in the middle of the intersection, angled towards the continuing bike route. I’m not sure I like the idea of sharrows as routefinding but they did make it easy to follow.

    • Of course, now I find pictures.

      (I’m not sure about the proposal for cycle tracks on Fell and Oak. I found Fell perfectly fine westbound, but the official route eastbound is a bit indirect and less pleasant through that section. Just one out-of-towner.)

  6. I’m worried about their slipperiness, too. I regularly skid (on foot!) on wet worn street markings when the glass beads wear off.

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