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Cities in a jam: reducing urban traffic congestion

As more people move into urban areas, threatening to jam the streets event further, cities globally are trialling and implementing various ideas to ease the gridlock and get people moving again

Congestion in Jakata
Congestion in Jakata

Traffic congestion -- along with people’s associated commute times and tempers, no doubt -- is on the rise and now stands at an all-time high. According to the latest Traffic Index from TomTom, congestion is up 23 per cent globally since 2008.


Congestion isn’t just an inconvenience, it can cause health-damaging air pollution, high stress and even higher crime. There’s an economic impact too. Research from the Texas A&M Transportation Institute found that travel delays due to traffic congestion cause drivers to waste more than 3 billion gallons of fuel and sit stuck in their cars for 7 billion extra hours -- that’s 42 hours per rush-hour commuter. The total nationwide price tag was estimated at $160 billion, or $960 per commuter.


As more people move into urban areas, threatening to jam the streets event further, cities globally are trialling and implementing various ideas to ease the gridlock and get people moving again.



HOV policies in Jakarta


One facet of reducing congestion is, of course, reducing the number of vehicles on the road, and a key way to do that is cut the number of single-occupancy vehicles and encourage car-pooling.


Jakarta’s traffic congestion problem is long-standing and well-known. The Indonesian city was ranked as the third most congested city globally in TomTom’s Traffic Index.


In 1992, Jakarta implemented HOV (high-occupancy vehicle) regulations, including a “three-in-one” policy that required three passengers in each vehicle on specific (major) roads during designated hours. However, the initiative drew some concern and criticism due to a ‘jockey’ system which emerged, whereby “jockeys” would charge a small fee to drivers and then ride in their cars, bringing vehicles up to the three-person requirement. There were questions as to whether the HOV policy was actually reducing congestion and encouraging genuine ride-sharing.


A sudden policy reversal in March 2016 gave quick-thinking researchers a chance to test out the impact of the HOV policy and compare before/after results -- the findings were recently published.


Almost immediately, the researchers began pulling Google Maps data on traffic speeds in Jakarta. This meant they were able to capture real-time traffic conditions while the HOV policy was still in effect and compare it to the changes in traffic after the policy change.


After the HOV policy was abandoned, the average speed of Jakarta’s rush hour traffic declined from about 17 to 12 miles per hour in the mornings, and from about 13 to 7 miles per hour in the evenings (People typically walk at around 3 miles per hour.) Travel delays became 46 per cent worse during the morning rush hour and 87 per cent worse during the evening rush hour Further, traffic also got significantly worse on surrounding roads.


Rema Hanna, the Jeffrey Cheah Professor of South-East Asia Studies at the Harvard Kennedy School and one of the researchers, says the findings are particularly interesting since the sudden change in policy reduces the possibility that other factors were at work.


She notes that HOV policies could offer a simple, low-cost solution to traffic congestion. This is particularly important in emerging countries such as Indonesia, which may want to ultimately work towards systems such as electronic road pricing but not yet have the infrastructure in place.


The results of the study were fed back to the City of Jakarta.



‘Talking’ traffic lights for smarter streets


Another important consideration is to keep the traffic that is on the streets moving. In Pittsburgh, a smart traffic lights system has been proven to reduce travel times by 25 per cent, the number of stoppages by 30 per cent and idle time by 40 per cent.


Stephen Smith, a Research Professor in Robotics at Carnegie Mellon University, spotted an opportunity to use his field of interest in the area of traffic. He explained: “You really need technology where multiple decision-makers have to collaborate together to achieve co-ordinated behaviour.”


The system is based on a ’decentralised’ approach. Each intersection controls its own local traffic by watching the approaching traffic through video cameras and even radars, then building a model of that traffic. In real-time, the intersection builds a timing plan for allocating the green light in order to move the traffic in the most efficient way possible. It then sends that plan to the hardware controller that manages the lights and also communicates it to neighbouring intersections.


Smith says: “It’s very real time. Every two seconds we generate a new plan and then we keep executing the front end of it and go from there.”


The work started out with nine test intersections in Pittsburgh. This has gradually been increased to 50 and the results have been replicated across this growth. In 2015, the company Rapid Flow Technologies spun out of Carnegie Mellon. There are plans to add a further 150 smart intersections in Pittsburgh over the next two years, as well as to launch in other US cities.


Back at the university, Smith is researching a number of related areas to reduce congestion, including integration of real-time traffic signal control with connected vehicle technology. Another project is looking at using radio technology on buses to predict when buses will reach an intersection and, since they tend to block other traffic, to “intelligently” give them priority -- that is in a way that doesn’t disregard all the other traffic.



Money walks?


Changing people’s behaviour is hard and some cities are using financial nudges to try to control traffic and encourage people to use other modes of transport. These initiatives continue to evolve over time. In 2003, London was one of the first cities in the world to introduce a congestion charge. It remains in operation Monday to Friday 07:00-18:00 within a specified area of central London. The tariff is fixed per day and enforcement is primarily based on automatic number plate recognition.


Revenue from the Congestion Charge is spent on further improvements to transport across London. According to TfL, which operates the charge, traffic entering the original charging zone has remained stable at 27 per cent lower than pre-charging conditions, meaning that nearly 80,000 fewer cars enter the original charging zone each day.


However, a report earlier this year from the cross-party Transport Committee called for change, noting that “the Congestion Charge is no longer fit for purpose,” calling it “a blunt instrument using old technology that covers a tiny part of London”. The report called for a new citywide road pricing scheme, which charges vehicles according to the extent, location and timing of their road usage.


In a draft transport strategy released last month, which was focused around encouraging walking, cycling and public transport over driving, London’s Mayor, Sadiq Khan, said that Transport for London will explore “the next generation of road user charging that could harness new technology to better reflect distance, time, emissions, road danger and other factors in an integrated way.” This could include a single ’per mile’ charge which takes into account both congestion and emissions objectives.



Blended mobility


The City of Stockholm also has a congestion tax -- the amounts charged fluctuate, and are highest during the periods and in the places where the traffic is heaviest. This year, Stockholm won the Blended Mobility Award in the TomTom Index. The city was praised for its holistic approach to tackling congestion, including this charge, as well as planning public transportation in context with housing and workplaces; additional ferry lines; a new traffic management centre; a new tunnel and expanded terminal for commuter trains; and advanced traffic analytics, as well as optimized traffic lights and projects to increase off-peak deliveries of goods.


When asked which initiatives have been particularly successful, Gustaf Landahl, Head of the Department of Planning & Environment, City of Stockholm, said: “The congestion taxation has had a strong and continued effect on reducing traffic,” noting it has reduced volume in rush hours by approximately 20 per cent.


He urges other cities considering this measure, “Start with a trial on congestion charging before having a referendum. When people see the positive effects, their doubts can be handled.”


These are just a few examples of the initiatives cities have in place for managing traffic but it’s clear there is no one magic recipe for reducing congestion. However, the goal for many cities is increasingly common, as

Mayor Khan said: “We have to make not using your car the affordable, safest and most convenient option.”



If you liked this, you may wish to view the following:



Think smart to tackle future traffic, by Dr. Graham Cookson, chief economist at INRIX

As cities are more likely to bear the brunt of this traffic growth, the only way to handle more people, more cars, more trips, more deliveries, and more congestion is to be smart




LA named as most traffic clogged city in the world

Thailand tops the 2016 country ranking with drivers spending an average of 61 hours in peak hours congestion





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