Tag Archives: traffic lights

Turning a busy road into a “smart corridor”

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The Illinois Department of Transportation has plans to create two new “smart corridors” along major suburban roads:

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The improvements include: traffic signal upgrades to modernize the corridors, synchronizing signals, dynamic message signs in strategic spots, and accommodations for pedestrians, officials said.

The Route 64 revamp stretches between Smith/Kautz Road and Route 50 (Cicero Avenue); the Route 56 redo runs from Route 59 to York Street.

For walkers and transit users, upgrades to sidewalks, crosswalks and pedestrian signals are coming, plus new, strategically located bus stops that expedite traffic flow.

“The long-range idea is to get those corridors working as efficiently as possible and to help support transit and buses,” IDOT District 1 Program Development Engineer John Baszek said.

These are busy roads – tens of thousands of vehicles each day – with high rates of speed. The project seems to have two goals: (1) improve traffic flow and (2) facilitate use beyond cars and trucks. Can both be done at the same time?

Not only have I driven these roads, I have biked along both roads. There is a lot that would have to be done to make this feel like a safe and pleasant experience for bicyclists and pedestrians. Having more cars flowing more efficiently does not seem like it necessarily fits with this.

As a driver, synchronized lights seem to make a lot of sense. On some of the regular routes I drive, I am pretty sure the lights are intentionally not in my favor; i.e., I turn left at the green arrow from one major road to the next and am immediately met with a red light. Keeping traffic flowing would seem to be good for congestion and the environment (through avoiding idling and stopping and starting).

Putting together statistical data and experiences, Right Turn on Red edition

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A discussion of Red Turn on Red (ROTR) pits statistical evidence and experiential data:

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Critics of the D.C. bill have pointed out the lack of data showing the dangers of RTOR, but many people who don’t use cars know instinctively how dangerous turning vehicles can be. “Our current safety studies fail to capture the reality of the constant near misses and confrontations that result between these motorists and pedestrians, which can be observed daily just by observing a typical busy intersection with RTOR,” Schultheiss says.

When teaching a research methods class, I can often come back to this observation about how sociologists approach data and evidence: we want both “facts” and “interpretations” to get the complete story of what is going on. In this particular situation, here is what that might mean: even if the statistical data suggests ROTR is not very dangerous, it matters that people still fear cars turning right on red. The experiences of pedestrians, bicyclists, and others on sidewalks and streets is part of the larger picture of understanding turning right on red. This would go alongside the data and experiences of vehicles and drivers.

Once this full set of data is collected, making policy decisions is another matter. If leaders want to prioritize vehicles, that is one choice. Or, as the piece suggests, some cities want to rethink streets and transportation, and they can end ROTR. But, it would be advisable to have all of the evidence before acting.

Limited solutions to ensuring more long green light stretches of suburban driving

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After occasionally finding stretches of hitting all green lights on major suburban roadways, I wanted to consider how these experiences might become more common. Is it possible? Here are some strategies alongside my sense of whether these would help.

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  1. Synchronizing traffic lights. Los Angeles did this a few years ago to help traffic flow. As a kid, I recall sitting in the car in Chicago and hearing tell of how Clark Street on Chicago’s North Side was set up this way: follow the speed limit and a driver should hit multiple greens in a row. This could be harder to accomplish across a range of municipalities and the various traffic volumes intersecting with the main road. Additionally, this might not help much if there is just too much traffic on the road.
  2. Providing more lanes, more driving options. Americans tend to like this strategy: more lanes, more roads equals more space for vehicles, right? Research suggests otherwise: if you add road capacity, drivers will tend to fill that up. Americans like driving in the suburbs and this is not a long-term solution. In fact, road diets may be more helpful: reduce capacity and it pushes drivers toward other options. Furthermore, expanding roads in an already developed suburban area can get quite expensive and may be controversial.
  3. Encouraging more mass transit use, more walking and bicycling, and less driving. If there are simply too many cars, limiting trips would help ensure smoother driving experiences. All of these options are tough sells in the suburbs. It is hard to provide mass transit in a decentralized landscape and wealthier residents are unlikely to use it. Residential neighborhoods might be set up for biking and walking but connecting to other uses – grocery stores, schools, businesses – is often not possible or is dangerous.
  4. Having more employees work from home. This may be temporary due to COVID-19 but could be a long-term solution for traffic and congestion issues. Of course, there may be more people living in the suburbs due to COVID-19.

This suggests that there may be some short-term solutions but the bigger issue would take more time and effort: American suburbs are built around driving.

The magic of 10+ minutes of green lights on a major suburban road

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I occasionally drive on major local suburban roadways. Think four lanes, direct north/south or east/west routes, speed limits of 35-45 mph, and lined with strip malls, fast food restaurants, gas stations, big box stores, and various other uses. Because of all of the traffic that wants to get on and off the road and because there are regulations about how to do this safely, such roads have regular traffic lights.

In the suburban road logic, these motorways are necessary to move larger volumes of traffic. Off these major roads are endless residential streets lined with single-family homes or small multi-family housing units. Traffic could cut through some of these neighborhoods but they have lower speed limits, narrower streets, and plenty of stop signs.

Occasionally, by finding the right time of day or the right position within the flow of traffic or finding the communities that have timed their traffic lights well, you can drive down such roads for ten-plus minutes without hitting a red light. It is smooth sailing. It is a slower but local highway. You can improve your gas mileage.

But, this is rare. During busier times, there may be too much traffic to get through each light. Late at night, the side streets might have sensors that turn their direction to green when just one car arrives. The drive becomes a series of stops and starts. Up to 40 mph, stop again, back up to 35 mpg, stop again.

Thus, when in the middle of a magical moment without stoplights impeding your path, enjoy it. Hear a few songs in a row while moving. Look at the communities as you go by. Marvel at the ground that can be covered when moving at the speed limit for more than a few minutes. Soon you will be back at a traffic light, waiting to get started again.

My 2.4 mile drive to work includes 6 stop signs, 2 traffic lights, and 1 train crossing

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In my daily drive (or bicycle ride) to work through mostly residential neighborhoods, I encounter multiple intersections that require stopping with six stop signs, two traffic lights, and one trip over railroad tracks. A few patterns for my suburban trip and including these stops:

-The majority of the stops occur along an important north-south road in the community that is one lane each way, goes past houses of various kinds, and has a speed limit of 30 mph. Both traffic lights involve this road with only one light involving a four lane road.

-My average speed is roughly 12.5 mph. If I could go the 30 mph allowed on most of the trip and there were no stops, my trip should be more like 5 minutes long.

-Most of the stops are pretty short except for two kinds. The traffic lights can cause a wait of up to a minute and a half and the busier one can be longer if I have to wait through multiple lights. The train crossing obviously can wreak havoc with a typical trip with a stop for the train and then heavier traffic afterward as a long line goes down the road. Most of the time, I do not encounter a train and I now have a decent sense of when the passenger trains come during the morning and evening rush hours.

The average American one-way commute is now 26.9 minutes so my commute is much shorter than many. But, that time factor can obscure distances – a 20 minute commute in a more rural area is going to cover more distance than my 12 minute drive in a residential suburb and a 35 minute commute in a major city might be a different distance.

One promise I have read about involving self-driving cars is that they will be much less impeded by intersections. Because vehicles will be able to communicate with each other, stopping at a stop light for 1+ minutes or a required stop at a stop sign in light or no traffic could be limited. Removing all that stopping and starting would also be good for the environment because of reduced idling.

I assume all of the stops are there due to safety concerns and trying to keep traffic flowing in all directions (based on traffic counts, accident reports, and road and planning guidelines). But, it would be great to see in the next few decades changes to how many stops and starts vehicles must make.

Forget smart cars; we should at least have smart traffic lights everywhere

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Getting to the point where most or all American drivers have safe and reliable driverless cars will take time. In the meantime, why don’t we have smart traffic lights or at least every traffic light operating with sensors?

There are several intersections near my house and work that clearly do not have sensors. You pull up in your vehicle and regardless of time of day or how many others want to go the same way as you do, you will wait a full light cycle. Some of these lights are one to one and a half minutes long. Sometimes this makes sense: one road clearly has more cars. Yet, often this full period passes with few to no cars going through the light.

But, let’s go further. I’ve also run into situations where the sensors might just be too sensitive. This occurs particularly between 9 PM and 5 AM when traffic is light on major roads. A single vehicle wanting to turn onto the major road can stop traffic. If you have a few of these on a single trip, this can be frustrating. Why not have coordinated light signals along major corridors? Cities and suburbs do not necessarily have to go to full-blown smart systems that hope to coordinate all traffic; even just doing this on a few main roads with significant amounts of traffic could help ease congestion.

Perhaps one issue is cost: what municipalities or other governments (depending on who has jurisdiction over the road) want to spend money on sensors and devices? One of the supposed benefits of driverless cars is that they will allow for more flowing traffic through coordination across vehicles. However, in that scenario the cost of less congestion is pushed to the car owners who have to purchase such a vehicle. Sensors at major intersections or at all intersections would not require anything or much from drivers. Yet, I bet you could make an argument that putting money into better intersections will be a cost savings in the long run with less time spent in traffic.

Better ways to signal pedestrian crosswalks

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The death of a cyclist recently in Mount Prospect has led to an examination of how to stop drivers for walkers and bicyclists:

Using data from studies of 16,716 vehicles at crosswalks equipped with amber beacons in seven states, including Illinois, researchers found on average 72 percent of drivers yielded to pedestrians. Interestingly, only 33 percent out of 1,402 vehicles yielded in Illinois.

Drivers tended to stop more frequently if the amber beacons were located overhead instead of alongside the road, near a school or transit stop, and on roads with fewer lanes, the study stated.

A different Federal Highway Administration report found a huge gap in drivers obeying amber beacons at crosswalks that ranged from 19 percent at one site in Illinois to 98 percent at a Colorado location…

Meanwhile, another type of crosswalk signal with a red light offers a promising track record. Known as a pedestrian hybrid beacon, the device typically hangs over an intersection and is dark until someone presses a button activating a yellow warning light, then a red beacon for drivers.

Studies of 3,504 drivers in Texas and Arizona showed 96 percent on average stopped.

All the road signs and traffic lights in the world will not lead to 100% compliance from drivers. Of course, some solutions are more effective than others. Later in the article, an expert explains:

“Traffic engineering is harder than drivers may think,” Fitzpatrick said.

Another problem that could be solved with self-driving cars. Until then, cyclists and pedestrians have to be really careful with cars driven by humans who can have all sorts of reactions to people crossing the road.

Naperville mayoral candidates all want to fix traffic problems…but how?

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The four men running for mayor in Naperville agree that fixing traffic issues is important but differ on the solutions:

Walker says the city should adjust traffic signal timing street by street to alleviate common backups.

Jim Haselhorst says the city’s traffic problem needs a comprehensive solution because every time signals are adjusted on one street, drivers change their habits, causing backups elsewhere.

Steve Chirico says the planned implementation of an integrated traffic management system on Washington Street will help, as will good city planning to avoid creating future traffic nightmares.

And Doug Krause says the city needs to form better intergovernmental partnerships — since many roads in Naperville are managed by a township, a county or the state — and spend more on street improvements and maintenance.

This is an important issue for a suburb that claims a high quality of life (#33 in Money‘s recent list of best places to live) yet has a large population (the fifth largest city in Illinois). The problems stretch back decades: Naperville, like many Chicago suburbs, had a better system of east-west transportation (think the highways and trains on the hub and spoke model with Chicago); the city’s sprawling growth outpaced the local north-south roads; the proposed Fox Valley Freewayway never materialized; and mass transit does not adequately connect destinations along the north-south axis (though Pace and others always have plans). The best answer for these issues is probably that this should have all been planned for a long time ago. But, few people ever thought Naperville would have been this big.

Yet, I think simply talking about existing roads doesn’t do much. Traffic light synchronization should have been done a while ago if it is such a solution. Again, why weren’t plans implemented earlier on Washington Street to help traffic get through downtown? Widening roads may increase the number of lanes but this can also increase traffic volume which fills up those new lanes. Adding right-turn lanes could help at intersections but it can be a lot of work for relatively little new road space.

I would be interested to see some Naperville officials think big here. Single, easy solutions will be hard to find. Enhancing mass transit within Naperville and to other communities would help. A comprehensive and varied approach is needed, particularly if the city has any designs on denser development (which is what is needed if the city wants to continue to grow given its lack of large plots of open land).

How much driving time is saved by the completely synchronized LA traffic light system

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I noted the synchronization of all Los Angeles traffic lights a while back but a new piece in the New York Times describes how much time the new system is supposed to save drivers:

The system uses magnetic sensors in the road that measure the flow of traffic, hundreds of cameras and a centralized computer system that makes constant adjustments to keep cars moving as smoothly as possible. The city’s Transportation Department says the average speed of traffic across the city is 16 percent faster under the system, with delays at major intersections down 12 percent.

Without synchronization, it takes an average of 20 minutes to drive five miles on Los Angeles streets; with synchronization, it has fallen to 17.2 minutes, the city says. And the average speed on the city’s streets is now 17.3 miles per hour, up from 15 m.p.h. without synchronized lights.

Mayor Antonio R. Villaraigosa, who pledged to complete the system in his 2005 campaign, now presents it as a significant accomplishment as his two terms in office comes to an end in June. He argued that the system would also cut carbon emissions by reducing the number of times cars stop and start…

“If we reduce average travel time in Los Angeles by 20 percent, then we will see more people traveling,” Professor Moore said. “It’s money well spent, but part of the benefit is not speed, but throughput.”

These seem small fairly small changes, a few minutes for each average trip, but these would add up over time for individual drivers. Additionally, small improvements in a complex system like LA traffic could have very beneficial outcomes for the whole system.

But, as the article notes, these reduced times may not last long because more people want to drive. This is a rule of road construction: if you add lanes or improve traffic flow, more people will likely get on the road, limiting the benefits of changes. Sychronization of traffic lights may speed things up but there are larger issues at hand including the number of cars on the road and too much reliance on streets and highways to get people where they need to go.

Los Angeles “the first major city in the world to synchronize all of its traffic signals”

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Los Angeles, famous for its roads and highways, is now leading the world in having all synchronized traffic lights.

Mayor Antonio Villaraigosa was expected to flip the switch on Tuesday on a final traffic intersection system that will result in the synchronization of all of nearly 4,400 traffic signals in Los Angeles.

KNX 1070?s Pete Demetriou reports L.A. is about to become the first major city in the world to synchronize all of its traffic signals…

Officials said the completion of this project will increase travel speeds by 16 percent and reduces travel times by 12 percent…

Signal synchronization also dramatically reduces carbon emissions by 1 million metric tons a year due to less idling at intersections, according to officials.

Less congestion and greener? Sounds like a win-win.

It would be interesting to know the final costs and logistics involved from the full project. The article suggests this project was part of the planning for the 1984 Summer Olympics but was not completed until this week. If this is such a great benefit for the city, what is stopping other cities from doing the same thing?