Should traffic lights be synchronized?

Question

Do you think its stupid to drive from red light to red light with thousands of other people, wasting gas idling, putting brake pad and transmission plate chemicals into the air needlessly, and wasting a ton of time? All of that could be alleviated by synchronizing traffic lights so if you do the speed limit you make all the lights. It has been done before, why not do it now? If the country is at all serious about saving oil, its about time, don't you think?

Answer 1

Synchronization depends on the agency that controls the lights. Good transportation departments have experts who synchronize most signal systems. Low level transportation departments (for example some county and city transportation departments) usually don't have the equipment to synchronize lights or have engineers who are mediocre at synchronization. Lights are usually only synchronized if they are relatively close to one another, less than 1000 feet I think is the general rule. This is because at longer distances, variations in driver's speed (drivers who go much faster or much slower than predictions) makes synchronization less efficient. In addition, a series of signals can be synchronized but that does not mean you will not stop. This system is designed to minimize overall delay for all traffic in the area. It is impossible to have no delays from stopping for all traffic in an area with traffic signals... someone will get stopped eventually! Most signals are designed such that during peak hour all stopped traffic can clear on the next green.

Some European cities have very good synchronization schemes because the road networks are designed better and because most people drive manual transmissions ("drive a stick") which are annoying to downshift (and hurts the clutch). Some arrange their networks with interlocking circles, which would be hard to implement in American cities because of the construction cost and objections from the driving public.

Hope this helped to make it clearer. If you are truly concerned, call your local transportation department to find out who manages the light along your travel routes and possibly asked for them to do a traffic study of the area.

Answer 2

Traffic lights ARE synchronized. They work in unison with the posted speed limits. If you are exceeding the limit, either in conjunction with traffic or alone, you will not 'hit ' the light at the right moment and experience a delay in passing through it. I have lived in 6 major cities (Chicago, Philadelphia, etc) and know this to be a fact. Do the speed limit or less and you will 'time' the lights right.

Answer 3

In most major metropolitan areas they are coordinated (synchronized is an old and outdated term). Without that coordination you would have massive grid-lock.

Engineers, certified in Transportation, do take into account the speed of vehicles (called "system" speed) but they also have to take into account, the volume of vehicles, start up time (the interval between the signal going green and the vehicles actually starting to move), how long it takes a vehicle to reach the speed limit, the mix of automobiles, trucks, buses, motorcycles, etc.

From this, along with other data, the engineers use propietary software to eventually arrive at the "best" solution. "Perfect" solution being impossible, too many variables from day to day in the traffic patterns. This solution gives them the cycle length (how long it takes to service all approaches at an intersection), and other factors used in programming the controller to service the traffic.

Different cycles lengths are used during any given day; Morning peak cycle, noon peak cycle, afternoon peak cycle and off peak cycles are usually the minimum number of timing programs needed to preserve the progression of traffic.

Most major aterial roadways in metropolitan areas are programmed to work in this manner.

I believe that what you are thinking of is the old method of using pre-timed traffic signals, and with the growth of sophistication in traffic systems this mode is totally out of date.

There is one situation that will cause major congestion regardless of how the signals are timed. Each roadway is designed to "X" number of cars per lane per hour. Once this "X" number is exceeded the roadway is "saturated" and incapable of handling any more vehicles and ergo you have heavy congestion.

Answer 4

Some intersections are busier than others so if you synchronize them it would be an even longer wait. Imagine if there were no breaks at all in the traffic for people to get out in, it would be madness.

Answer 5

probably, but do you want to hear something even more rediculous? in the city i live in there is a downtown square, where all the lights on all four corners turn red at the same time. i am sure it is for peds but i mean, most of the time no one is around to be crossing the street and everyone just sits there in thier cars until the lights turn green, and when they do it is pandimonium to get a lane because all four corners are comming together at once. hehehe

Answer 6

If you synchronized traffic lights, someone will end up having to wait anyway. I think they should have a sensor that lets people go- busier area, more cars go through, slower area, less cars go through.

Answer 7

I absolutely agree with you. About 20 years ago, the mayor of San Jose CA said "We can't sync our traffic lights! That would cost $1 million".

Answer 8

In many cases the light are optimized for traffic flow. Just because you have to stop, doesn't mean they havent considered all this.

Answer 9

in certain cities they have sensors at the traffic lights. and they
control the traffic. when you pull up to a light and traffic
is slow the light turns green.

Answer 10

Um, some places do synchronize. Too bad your area doesn't.