How can a city reduce driving by 45%? Sustained effort over decades

Paris has significantly reduced traffic since 1990 but this was not an easy or quick task. This article suggests sustained effort from the city’s mayors was critical:

  • Jacques Chirac, Paris’ famously conservative (and public fund-embezzling) mayor from 1977 to 1995, helped encourage pedestrianism by increasing the number of bollards to prevent illegal sidewalk parking, Héran writes. Chirac also rehabilitated the Champs-Elysees into a true public promenade, with widened sidewalks, street parking eliminations, and refreshed green spaces.
  • Chirac’s chosen successor, Jean Tibéri, came under fire for not cracking down hard enough on Paris’ air quality problems (and was accused of election fraud!), but he does get credit for banning cars in the Place de la Concorde. In an effort to reduce traffic, he also introduced the city’s first bike plan in 1996, which established paths along the city’s main arteries and lower-speed neighborhood zones, Héran notes.
  • Elected Paris’ first openly gay mayor in 2001, the socialist Bertrand Delanoë “vowed that automobile interests would no longer dominate the city and he would focus on improving public spaces,” wrote Stephane Kirkland for the Project for Public Spaces in 2014. Delanoë made good on those promises during his 13-year tenure (while largely avoiding scandal): A number of streets were reconfigured to accommodate dedicated bus lanes. Some 400 miles of bicycle lanes were created. The banks of the Seine began to close to traffic in the summertime to make way for public “beaches.”And in 2007, the city introduced its bikeshare program, Vélib, now arguably the largest and most used such system in the West.
  • Delanoë’s protégé and current Mayor Anne Hidalgo is an outspoken environmentalist responsible for “some of the most systematically anti-car policies of any major world city,” CityLab’s Feargus O’Sullivan wrote last year. Hidalgo has implemented a ban on older cars on roads during weekdays, and has pedestrianized the lower quays of the Seine. “Car space is being slashed in many major squares, while car-free days have been introduced annually as a form of publicity campaign for a future without automobiles,” O’Sullivan wrote. (Furthermore, recent trip data from city hall do not support the claim by some motorists that Mayor Hidalgo’s car-free policies have made congestion worse. There’s been a sharp decline in the kilometers-traveled within the city, but only a small dip in kilometers-per-hour.)
  • Paris’ commitment to public transport far surpasses that of any city in the U.S., where it has been more than 30 decades since any new system opened. RATP, the public transport operator for the Île-de-France region, has increased its reach with new bus rapid-transit lines and a steadily growing suburban tram network whose first line opened in the early 1990s. New routes have been accompanied by sidewalk improvements, bike paths, and a variety of traffic calming measures. The lines are frequent and fast. Some are even driven autonomously.

Three quick thoughts regarding this brief history of Paris:

  1. Sustained effort across mayors and local government officials is not easy to do. This article covers 25+ years where different actors from different perspectives contributed to a desirable outcome. The amount of emphasis on reducing traffic probably differed quite a bit across administrations yet the small and big steps added up over time. Significant social change in large cities does not often happen quickly.
  2. The reasons for pursuing less car traffic are varied. Some might decry the environmental issues. Others might want more space for bicycling. More public space might motivate others. I wonder if any of these one reasons would have been enough to motivate these actions and push forward big changes. But, put together multiple reasons and people with different interests might be more likely to come together and promote fewer cars.
  3. How much easier is it to pursue such plans in a European city versus an American city? Additionally, this is Paris, a tourist hot-spot where people want to walk around and experience charming sights and neighborhoods. American cities may also desire less traffic – who wants to be delayed? – yet this is difficult to reconcile with American desires for individual transportation. At the same time, a chart in the article suggests London and Berlin are more like New York City in terms of driving.

Towns that restrict road access to app users only address the symptoms and not the bigger issue

The decision in a New Jersey suburb to fight back against drivers directed to their streets by apps raises all sorts of questions:

In mid-January, the borough’s police force will close 60 streets to all drivers aside from residents and people employed in the borough during the morning and afternoon rush periods, effectively taking most of the town out of circulation for the popular traffic apps — and for everyone else, for that matter…

But Leonia is not alone. From Medford, Mass. to Fremont, Calif., communities are grappling with the local gridlock caused by well-intentioned traffic apps like Waze, which was purchased by Google in 2013 for $1.15 billion.

Since Waze uses crowd sourcing to update its information, some people — frustrated at the influx of outside traffic — have taken to fabricating reports of traffic accidents in their communities to try to deter the app from sending motorists their way. One suburb of Tel Aviv has even sued Waze, which was developed by an Israeli company….

“It’s a slippery slope,” said Samuel I. Schwartz, the former traffic engineer for New York City known as Gridlock Sam, and the author of the early 1990s book “Shadow Traffic’s New York Shortcuts and Traffic Tips.” “Waze and other services are upsetting the apple cart in a lot of communities. But these are public streets, so where do you draw the line?”

See an earlier post about a Los Angeles neighborhood that raised similar objections.

I can see the reasoning by small communities: the roads are partly or mostly paid for through local tax dollars and thus they should primarily be reserved for the use of locals. These sorts of situations can become big deals in suburbs where residents are often resentful of ways that their local tax monies serve others.

At the same time, this hints at a larger issue: efforts like this by single communities could end up having deleterious effects on the region as a whole. What if every suburb or community employed such tactics? Traffic would only be worse. This then suggests a metropolitan approach is needed to tackle these congestion issues. This might be difficult to do considering how local residents like to hold onto their own monies but drivers across the region might be too mad at that point to care if there are no alternative routes. The best way to tackle this issue may be to lobby for more mass transit and decreased reliance on cars in the New Jersey suburbs.

Study suggests traffic would flow much faster if we kept the proper distance between cars

The science of traffic once again suggests we all could be driving faster if we followed a simple rule:

But a new study in IEEE Transactions on Intelligent Transportation Systems mathematically models the implications of the larger problem: You’re not keeping the right distance from the car behind you.

That may seem counterintuitive, since you don’t have much control over how far you are from the car behind you—especially when that person is a tailgater. But the math says that if everyone kept an equal distance between the cars ahead and behind, all spaced out in a more orderly fashion, traffic would move almost twice as quickly. Now sure, you’re probably not going to convince everyone on the road to do that. Still, the finding could be a simple yet powerful way to optimize semi-autonomous cars long before the fully self-driving car of tomorrow arrives.

Traffic is perhaps the world’s most infuriating example of what’s known as an emergent property. Meaning, lots of individual things forming together to create something more complex. Emergent properties are usually quite astounding. You’ve probably seen video of starlings forming a murmuration, a great shifting blob of thousands upon thousands of birds.

But it feels so much better to let that pokey driver ahead know you are there by following closely!

For an earlier blog post about how science could improve traffic, read about zipper merges and other individual actions drivers can take.

Solving traffic problems by developing resilient roads

A new study suggests cities and regions should think about their whole network of roads as resilient rather than focusing on main arteries:

In a paper published Wednesday in the journal Science Advances, Maksim Kitsak, associate research scientist in the Department of Physics and Northeastern’s Network Science Institute, and his colleagues examine the resilience and efficiency in city transportation systems. Efficiency refers to the average time delay a commuter would face annually due to traffic. Resilience is the ability of road networks to absorb adverse events that fall outside normal daily traffic patterns…

“What we show is actually these two measures are not really correlated with each other,” Kitsak said. “One would think that if the city is bad for traffic under normal conditions, it would be equally bad or worse for traffic under additional stress events, like severe weather. But we show that is not quite the case.”

For example, the study found that the Los Angeles transportation network—while inefficient on a daily basis—doesn’t suffer much from adverse events. The road systems are resilient. They function more or less the same regardless of unforeseen incidents…

Why is the City of Angels more resilient than the City by the Bay? Kitsak said there are many factors that influence transportation resiliency, but one of the most important ones is the availability of backup roads. Los Angeles has many, while San Francisco does not. San Francisco also relies heavily on bridges, which separate the city from other parts of the Bay Area where many commuters live.

This is more evidence that simply adding lanes to major highways or even constructing more major roads is not necessarily the way to go to solve traffic and congestion issues. All the roads (plus other transportation options) work together in a system or network.

Speaking of Los Angeles, this reminds me that the region can illustrate both the good and bad of having a more resilient road network. On the good side, concern about potential Carmageddon and Carmageddon 2 were overblown as the closing of a major highway for repairs was not as disruptive as some thought. On the flip side, a few years ago some Los Angeles residents complained about Waze rerouting cars through their quiet neighborhood to avoid backups on the main roads.

Finally, this study could also be related to claims by New Urbanists that the best option for laying out roads and space is on a grid system. Grids allow drivers and other easy ways to get around problem spots. In contrast, subdivisions (common in suburban areas) that include quiet and occasionally winding residential roads that dump onto clogged main arteries do not contain many alternatives should something go wrong on the main roads.

So is the trick in the long run to create a resilient road network within a region that is not totally dependent on cars? Los Angeles might come up looking good in this study but not everyone would agree that sprawl and lots and driving is desirable.

What social level should help better protect Illinois pedestrians in crosswalks?

The Daily Herald did an “informal study” of using crosswalks in the suburbs and the results were not good for pedestrians:

Daily Herald journalists conducted 49 tests of crosswalks not connected with stop signs or traffic lights in Cook, DuPage, Kane and Lake counties in November and December. Among the findings in the informal study:

• In 20 percent of tests, drivers whizzed through crosswalks despite a reporter either standing or walking within the striped area.

• Walkers were temporarily stranded in the middle of crosswalks 12 percent of the time as traffic continued without allowing them to reach the other side.

• One reporter on a busy stretch of Central Road in Mount Prospect waited more than 10 minutes while at least 99 vehicles surged through the crosswalk at Emerson Street until a vehicle stopped. It took more than 99 vehicles until it was safe for the reporter to proceed.

• Ninety percent of the time, traffic continued through crosswalks without heeding people on the curb.

Illinois’ nuanced law saying cars can continue through crosswalks until a pedestrian has both feet in the crosswalk is pure “Catch-22,” widower Eric Jakubowski of Mount Prospect thinks.

There are various levels that could be blamed for these issues:

  1. Local government. Why not put more stop signs or traffic lights in that would give pedestrians more help? (Easy answer: drivers do not want the flow of traffic impeded.) My own anecdotal evidence also suggests these traffic devices are also not guarantees for the safety of walkers, joggers, and bicyclists.
  2. Local law enforcement. Why is this law not enforced more? It reminds me of the cell phone laws in Illinois that are rarely enforced (and some communities have basically said as much).
  3. Pedestrians. Are they aggressive enough in stepping out into the street? Of course, one could hardly blame them as you often have to step out into traffic and catch the eye of drivers.
  4. State officials. Why not clarify the law so that pedestrians come first and also impose steeper penalties for lack of compliance?
  5. American society. Why must we privilege driving so much? And the suburbs are particularly designed around cars where people often have to go several miles to reach basic needs. Pedestrians slow down traffic and suburbanites dislike traffic. Different approaches to community life and urban design could help address these issues.

All of this is the case when many would suggest Americans should walk more for their own health as well as for building community.

AAA’s negative Thanksgiving traffic outlook a lot of common sense and normal conditions

Over a week ago, predictions by AAA about record Thanksgiving driving traffic started circulating. However, the reports did not add much useful information. Here is how the Chicago Tribune summarized it:

In fact, Chicago is expected to log one of the worst traffic jams of any big city during the Thanksgiving holiday season on Tuesday afternoon, according to an analysis by AAA and global transportation analytics company INRIX. Motorists should beware that the worst time will be between 5 p.m. and 6 p.m. Tuesday, when holiday travelers are expected to join post-work commuters on Chicago-area interstates. Already long travel times could quadruple, according to AAA…

In Chicago, area interstates may not only see one of the worst traffic jams over the holidays, the city also may come in second place for longest commute times to a major airport, analysts predict. The absolute worst time to take the Kennedy Expressway between downtown and O’Hare International Airport is 4:30 p.m. to 5:30 p.m Tuesday, when it could take an hour and 14 minutes, the analysis shows. Only a trip to New York’s Kennedy International Airport — the same day and around the same time of day — is longer at nearly two hours.

And from

Based on historical and recent travel trends for the holiday week, INRIX, in collaboration with AAA, predicts drivers will experience the greatest amount of congestion during the early evening – as early as Tuesday of Thanksgiving week – as commuters mix with holiday travelers. At its peak, drivers on Chicago’s interstates, for example, could see a delay of nearly 300 percent over the optimal trip.

“Thanksgiving has historically been one of the busiest holidays for road trips, and this year we could see record-level travel delays,” says Bob Pishue, transportation analyst at INRIX. “Knowing when and where congestion will build can help drivers avoid the stress of sitting in traffic.”

Two quick thoughts regarding this data. First, traveling during rush hour is a bad idea in any major American city. There are simply too many vehicles on the highways at these times and the traffic flows everywhere these days, not just into the city in the morning and out in the evening. Whether planning relatively short or long drives, it is necessary to plan to avoid rush hour.

Second, saying that the delay in Chicago could be “nearly 300 percent over the optimal trip” or the trip from downtown to O’Hare will take slightly over an hour is really not that abnormal. Perhaps the key is the comparison to the “optimal trip” which in metropolitan areas tends to be somewhere between 8 PM and 6 AM when truck and car travel is limited. I have this optimal trip in mind all the time when I make a drive to the local airports: without traffic, the trip takes this amount of time but adjustments need to be made for any daytime or early evening hours. In the Chicago area, all it takes is a little rain or snow or an accident and the Thanksgiving travel times predicted here are fairly normal occurrences.

All that said, this is good PR for AAA. Americans may like driving but they do not like traffic.

The roundabout capital of the United States is…

As Chicago area drivers disagree about existing and proposed roundabouts, the roundabout capital of the US is revealed:

Booster Dan McFeely of Carmel, Indiana, wants Illinois to embrace roundabouts.

“We have built 102 roundabouts to date, the most of any city in America,” said McFeely, Carmel’s economic development director. ” … We have steadily added them to Carmel over the past 20 years. They work wonderfully. And yes, we’ve seen a steady decline in accidents with injury.”

Carmel is regularly ranked as one of the best places to live in America. (It just took the #1 spot in’s 2017 rankings. It also has done well in Money‘s rankings, taking the top spot in 2012.) Who knew the secret to their success was roundabouts?

As long as there are enough lanes and not so much traffic that people can easily enter the roundabout, I’m all for them. As a driver, I find little worse than traffic lights on timers where you sit for a long period of time with no cross traffic.

One interesting aside from seeing a suburban debate over a roundabout in recent years: they can take up a good amount of room compared to a traditional intersection. Therefore, they might be difficult to implement in older locations or where buildings are relatively close to the road.