(This is a 2-part column since there are actually 17 wonderments) (seriously)
Unusual signs are one of the many topics addressed in traffic engineering journals (I’m assuming this — I’m not sure traffic engineering journals are actually a thing). And because many of you may not read traffic engineering journals (not regularly anyway), I now address the top eight questions/comments received by you, the reader. And should you, the reader, have particular questions/comments, please note I read every email. OK, it’s time to answer the top eight — buckle up!
- Why must I drive counterclockwise in roundabouts? That’s only true in the northern hemisphere — in the southern hemisphere you must drive clockwise. Consequently, roundabouts are not permitted along the equator (that’s why many people are moving to Pekanbaru).
- What’s up with flashing yellow arrows? Flashing yellow arrows (FYA’s) allow vehicles waiting within the intersection to turn left when the signal turns red and before conflicting traffic receives a green light. Thus, avoiding the “Yellow Trap Dilemma” (the movie is better than the book). Unfortunately, not all intersections are candidates for FYA’s (more on this in a future column).
- Why do some roundabouts have two circulating lanes even though the adjacent roadway has only one receiving lane? I don’t know.
- How do I make my car autonomous? Third-party devices are available to add an increasing number of autonomous features to the car you presently own — you do not need to buy a Waymo, Baidu, or a Tesla — but I suppose that depends on how you define need.
- I’ve noticed most traffic signals have a red light on top and a green light on the bottom (or maybe it’s the other way around). Why is that? Also, where can I buy bowling shoes? Let me answer the second question last. Most traffic signals have the red light on top because historically it was a higher wattage bulb and heat rises. Also, something to do with wavelength, color blindness, and the universal importance of the color red. And I forgot your other question.
- I’ve noticed some emergency vehicles trigger the green light a quarter mile away. How do they do that? I’m curious. It’s a simple device, to receive one, simply become a police officer, fireman, or ambulance driver. The device “shakes hands” with the traffic signal controller, your vehicle information is recorded (yep), the signal phasing is accelerated, and a green light is displayed until you pass.
- When I pull up to a 4-way stop sign, I go first, right? The car arriving first has the right of way. And if you both “arrive first,” the car that arrived firster, goes next. And in the case of exactly simultaneous arrivals (a physical impossibility) the car on the right has the right of way. And because some drivers are more important than others, common sense often prevents fender benders.
- How long do I have to pull over when a police car is behind me with his lights on? Pull over right now — you can read this column later — while he’s running your plates.
Chet Skwarcan (traffic engineer, author, unique insights) with over 25 years of traffic engineering experience — online ideas available at TrafficEngineering.com/Services or Chet@TrafficEngineering.com.