If a traffic signal's cycle is too long or too short, will the DOT change it?
Possibly. If your opinion is that a signal's cycle is too long or too short, you could contact the DOT or county or municipal road maintenance department and speak to the traffic engineering department about it.
However, it may also be their opinion that the cycles is just fine, thank you. Unless, of course, many people besides yourself have complained about the same intersection.
The good news is that most municipalities will monitor traffic flow at busier intersections periodically, and will note that traffic backs up beyond normal at busy or not-so-busy times of day, and can make recommendations to the traffic engineers that such-and-such an intersection appears to have inordinate back-ups or delays due to the length (too short or too long) of the light signal.
How does DOT decide whether a traffic signal should be installed at an intersection?
Since I've never worked for the USDOT or any state DOT, I am going to hazard an educated guess, having worked on several private road or street projects with various DOT's.
Similar to what I said in the previous segment, the DOT will monitor traffic using pneumatic road tubes across roads or streets in various locations, such as where it is evident that more homes are being built, a school will be built, or commercial development is taking place.
If it is noted that an area has an elevated traffic flow, and that traffic is getting too heavy or backed up at a STOP sign, for instance, the DOT or municipal road department will frequently add a traffic signal at that intersection. Increasingly, and unfortunately in my opinion, municipal and county road departments are using "roundabouts," which in my opinion are a hindrance to traffic flow unless it's a low traffic intersection, and if that is the case, it costs maybe $1500-2000 to add 4-way Stop signs, but roundabouts cost upwards of $50,000 on the low-end.
Most municipal road departments also know, because of various building permitting processes, where a school or shopping mall will be built, and often part of the requirements for putting in the shopping mall will be for the commercial construction firm to add new streets, traffic signals, and various traffic control signs or signals, like electronic crosswalk signs.
How do the standards for traffic signals accommodate the needs of color-vision deficient drivers? Would it be better to add shapes to the signal indications to help the color-vision deficient to identify what signal is on?
Traffic signal lights are very bright LED's, so if a person has color-deficient vision, more commonly known as "color blindness," they are required under current law to know that green is on the bottom, yellow is in the middle, and red is on the top.
In our opinion, there is no need to add shapes to the current configuration, but if you want to start a signal manufacturing firm that could popularize this idea, then lobby some congressmen to pass a law, you could make yourself a literal fortune. That's how it's done these days. Provide a semi-useless idea, make some high-powered friends, cut them in on some of the profits, and ¡voila! You're rich!
Click here for more about traffic signs as approved by the US Department of Transportation.
ABOUT THE AUTHOR
Barry K. Brown has been in the Sign, Banner, Decal and Display Business for over 20 years. It isn't what he thought he'd do with his life, but he says he knows too much now to do anything else!
He has been marketing these products online since 1998, and the company he was general manager of in 1998 was the first sign company to be listed on Yahoo!