Exploring public transit solutions to congestion-related emissions.
Growth in cities has accelerated since the dawn of the industrial revolution. The invention of the automobile revolutionized the way we transport ourselves. Cities have had to adapt to this change by providing infrastructure to support a growing population of automobile users. Older cities, which have existed long before automobiles, had to find ways to accommodate cars within their existing infrastructure. Conversely, new or growing cities like Edmonton designed themselves around the automobile. Urban researchers Newman, Kosonen, and Kenworthy (2016) note, “cities in the new world in the past 70 years have grown mostly with automobile-dependent suburbs” (p.436). In the case of older cities, the introduction of automobiles to densely populated city centers has created issues of smog, congestion, and high accident rates. Congestion is an issue that plagues these differently designed cities. A city of this type will have a significant group of automobile users. As populations grow, the existing automobile infrastructure will not be able to support the growing demand, and congestion will increase further. As congestion increases, so do travel delays and pollution, which will negatively impact the city and its residents in the short and long-term. I will explore solutions that would reduce congestion in a growing city like Edmonton and evaluate which transit solutions are the most effective. In this article, I will answer the question: how are growing cities using public transit to reduce overall congestion? Upon reviewing some case studies in Bogota, Bergen, and Hong Kong, I will conclude with a transit-oriented solution that Edmonton can implement.
Congestion
Congestion occurs when a large volume of traffic occupies the same space on the road at the same time. Reasons for congestion include: heavy traffic flow, frequently accelerating and decelerating vehicles, and induced demand. Induced demand is a term to describe traffic that occurs as a result of roads being built. Often we think building new roads will decrease traffic, but ignoring induced demand can result in severely underestimating the amount of infrastructure needed to truly reduce congestion. When a road is already heavily congested, there is often a latent demand for the road. If the amount of latent demand is not measured and accounted for, new infrastructure will become congested. Researchers Næss, Nicolaisen, and Strand (2012) state, “road improvement generally tends to increase overall traffic volumes due to lower cost of traffic in the form of less time spent to reach a given destination. The effect of induced traffic is now widely accepted among transport researchers” (p.293).
Congestion happens when there are high volumes of traffic accelerating and decelerating. During non-rush hours, these minor stoppages do not typically affect the overall flow of traffic significantly. However, since our varying reaction times do not allow for a situation where everyone accelerates and decelerates at the same time, there is a slight delay that increases with the number of cars waiting to accelerate or decelerate.
Congestion is a concern for cities because they cause environmental, economic, and health issues. Increases in idle times contribute to overall CO2 emissions. Also, acceleration is the time when vehicles exhaust the most pollutants. Frequent acceleration and idling repeatedly occur in congestion.
Cities with large populations of drivers typically tackle the issue of smog and the health issues that come with it. Upon studying 83 urban areas, Levy, Buonocore, and von Stackelberg (2010) observed, “public health impacts of traffic during periods of congestion, associated with premature mortality from primary and secondary PM2.5 concentrations, are appreciable, with thousands of deaths per year and a monetized value of tens of billions of dollars per year” (p.9). In addition to the health risks associated with congestion, the economic drain because of wasted time is significant as well.
Travel delays attributed to congestion result in wasted time and fuel. Thus, businesses that rely on transportation of goods or people suffer because of congestion. A 2012 report by the Texas Technology Institute estimated congestion in the US causes 5.5 billion hours of travel delays. When factoring in wasted fuel, the total cost per year of congestion was approximately $121 Billion (Schrank, Eisele, & Lomax, 2012).
Public Transit
For this research paper, I will define “public transit” as shared transportation, to which the general public has access. Some examples include: light rail transit, buses, trains, and ferries. For my research, I will not include ride-sharing apps or taxies as forms of public transit.
Early theories about traffic congestion suggest that public transit contributes to congestion. The rationale is that, as funding for public transit increases, demands on the system will increase as well. Thus, as the demand for public transit increases, overall congestion will increase as a result of more transit options sharing the road. However, recent research by Michael Anderson suggests the opposite. Anderson (2013) concludes, “ceasing public transit service causes a marked increase in traffic delays. Our model calibration results predict a 0.189 minutes per mile (38%) increase in average delay…In comparison, our preferred RD estimate…finds that average delay increases 0.194 minutes per mile (47%)” (p.19). These results echo those of researchers Beaudoin and Lawell (2017), as they comment, “investments in public transit may have a co-benefit of congestion reduction” (p.113).
Public transit options that service areas with heavy congestion will have the greatest impact on overall congestion (Anderson, 2013). Transit options that transport the largest amount of people in the shortest amount of time will have the strongest negative correlation to vehicle use. This effect makes light rail transit (LRT) popular in cities, as they can connect large amounts of commuters to the most densely populated areas of cities in short amounts of time. Since congestion increases as population density increases, commuters save significantly more time by taking transit rather than driving.
Case Study: Bergen, Norway
We can study the case of Bergen, Norway to observe the effects that a light rail transit system can have on a city. Bergen is a moderately sized city, with a growing population of 280,000 struggling with urban sprawl. In 2010 they re-introduced a light rail system after their tram service was de-commissioned for the previous 45 years. The city stopped their tram service in 1965, and instead allocated funding to increased road infrastructure (Engebretsen, Christiansen, & Strand, 2017). The push for the light rail system came from a government objective that hoped to “meet increases in transportation demand in Norwegian cities without increasing passenger car traffic” (Engebretsen et al., 2017, p.111). Bergen also introduced a new high-frequency bus service to go along with the new light rail transit. Additionally, they increased road tolls and made some changes to their urban structure. Researchers Engebretsen et al. (2017) studied the effects of the light rail transit on travel behavior and observed, “during the period of 2009-2014, car traffic to and from Bergen city center decreased despite population growth. The decline coincided with a sharp rise in public transport after the light rail line was opened and a new high frequency bus system was introduced” (p.114). Their data suggests, “the increase in public transport is primarily a characteristic of areas served by light rail” (Engebretsen et al., 2017, p.115). Bergen successfully changed its transportation behavior behind the driving force of light rail transit and high-frequency buses.
Case Study: Bogotá, Columbia
Bogotá was struggling with its congestion issues in the late 90s and elected Enrique Peñalosa as their mayor. He revolutionized the way people transported themselves in Bogotá by introducing the TransMilenio, a “bus rapid transit” (BRT). The BRT was “84 kms in 2007, with a network of 387 kms” (Allport, Brown, Glaister, & Travers, 2008, p.70). An added benefit to the TransMileno was the dedicated bus lanes that it used. Peñalosa also added a long-range bicycle network to connect nearby towns and villages to the city center and imposed driving restrictions during peak hours. Peñalosa pushed a car-free culture in Bogotá. He was successful in significantly reducing congestion with the combination of a rapid transit bus service, restrictions on cars, and increased infrastructure for non-vehicle travel. However, the popularity of the TransMilenio had some negative effects, such as overcrowding. Researchers Allport et al. (2008) studied the project and referenced, “overcrowding that began in 2004, and rapidly became severe (89% of interviewees saw this as its main weakness in 2007)” (p.70). In 2008 Samuel Moreno was elected mayor, on a platform promising a subway system and increased infrastructure for cars. Unfortunately, he failed to get the subway built, and increased funding for vehicle infrastructure produced increases in congestion due to induced demand (The people's city: How Bogotá succeeded in reducing traffic congestion and smog. 2009). In this case study, the TransMilenio was very effective at reducing congestion. The Centre for Public Impact states that it contributes to a 32% reduction in travel time and a 40% reduction in air pollutants (“TransMilenio: renewing Bogota’s transport system”, 2016). One of the limitations of high-frequency buses is that they cannot transport a large number of people in one trip (compared to the LRT). They also add vehicles on the road when higher volumes of commuters must be serviced. There is a limit to how effective buses alone can be at reducing congestion, especially in highly populated urban areas. What I can conclude from the two distinct approaches to reducing congestion in Bogotá is that reducing car use will yield lower amounts of congestion.
Case Study: Hong Kong, China
Factors that contribute to congestion are incredibly prevalent in Hong Kong. As researchers Allport et al. (2008) summarized, “Hong Kong is a city-state with 7 million people living in a land area of 1099 square kilometres, concentrated in very dense corridors (only 17% of the land area is built-up) making 11 million trips/ day” (p.172). They go on to note, “there are about 275 licensed vehicles per kilometre of road, and the topography makes it very difficult to provide additional road capacity in the built-up areas” (Allport et al., 2008, p.172). These conditions are not ideal when striving to reduce congestion since the enormous population must fit within existing infrastructure that cannot expand. A major solution to reducing congestion in Hong Kong is their Mass Transit Railway (MTR). Fleets of double-decker rapid-transport buses support the MTR in Hong Kong’s mission to control congestion. The estimated rail ridership in 2003 was 3 million passengers per day (Allport et al., 2008). The effect of the MTR is considerable in Hong Kong since it not only reduces congestion, but also provides a positive environmental impact by reducing air and noise pollution. It is mostly underground, and aboveground sections feature noise shielding (Allport et al., 2008). Hong Kong’s effort to reduce air pollution is common in many cities around the world that are densely populated. Air pollution becomes an imminent health risk with the high levels of congestion that they face.
Analysis
Congestion is an issue that plagues many urban areas to varying degrees. Growing cities often do not have existing infrastructure to support the movement of large amounts of people within their city limits. Solving the problem of congestion first requires us to understand the unique demands of a given urban space. By attempting to increase infrastructure alone, congestion can increase because of induced demand. Typically, development occurs around new roads. These additions increase the demand for the new roads and can draw more users to them. If only one form of transit is funded and utilized, it can boost demand for it to the point that its capacity becomes saturated, as was the case of the TransMileno in Bogotá.
High-frequency buses are an excellent way to provide access to transit hubs like train stations. On their own, high-frequency buses were effective at reducing congestion in Bogotá. When paired with another form of transit, as in the case of Bergen and Hong Kong, the results were formidable. Since most cities already have infrastructure to support buses, increasing their frequency is a cost-effective method to improve access around the city compared to major infrastructure projects.
For cities with the available funding to improve transit infrastructure, investing in light rail transit or train systems is another effective way to transport many people. Bergen is an excellent example of a combination of transit options reducing congestion in a growing city. Hong Kong illustrates how the rapid-transit buses and trains are a necessity to control congestion in highly populated cities. Newman et al. (2016) emphasized:
Congested traffic now means that average car travel is less than 35 km/h and thus many people in outer suburbs are trapped in travel-time budgets beyond their desirable limit. New fast trains (averaging over 80 km/h) can extend the transit city out beyond the previous maximum distances and well beyond the 20 km radius of the transit city (see the case study on Perth in McIntosh et al., 2013, where new urban rail lines extend 40 to 70 km from the city centre). These fast trains are thus changing the nature of automobile dependence by providing an option that the automobile cannot provide. (p.437)
Many factors that affect congestion fall outside of the scope of public transit. Although this research paper outlines the most effective ways in which transit can reduce congestion, factors like land development and active transport infrastructure should influence urban policy. Transit is one component of urban travel, and it is important to realize its limitations and how it is affected by urban design. The advantage of transit is its already existing infrastructure and ease of implementation in most cities.
Conclusion
Growing cities are reducing congestion by using multifaceted approaches that include new infrastructure, road tolls, and public transit. When public transit is involved, high-frequency buses that provide access to transit hubs are an efficient way of reducing congestion. The LRT offers a solution to traffic congestion by providing a mode of transport that is faster and more efficient than driving. By combining high-frequency buses with expanding light rail transit, sprawling cities can curb the rate of sprawl and relieve congestion. Of the case studies I reviewed, Bergen was that which was most similar to Edmonton regarding infrastructure development. Their use of the LRT, in combination with high-frequency buses, offers time savings that driving cannot. The impact that high-frequency buses had in Bogotá provides an example of the effect they can have on their own. The combination of rail systems and high-frequency buses is quite effective. It was used in Bergen (a smaller growing city) to reduce congestion and control urban sprawl. Additionally, it helped manage congestion in a megacity like Hong Kong.
In Edmonton, we currently have two LRT lines and a regular bussing system. Considering the impact high-frequency bus services has on cities that vary in population, density, and infrastructure development, I would recommend that the City of Edmonton implement a high-frequency bus service to connect our expanding LRT system to the sparsely located communities in the city. In my experience, most neighborhoods have 30-minute bus frequencies to connect them to the nearest bus terminal. Considering that it takes around 30 minutes to drive from one end of the city to the other, this long wait time does not offer any time saving compared to driving. If Edmonton introduces a high-frequency bus service with 5-10 minute frequencies connecting neighborhoods to LRT stations and major bus stations, a more attractive time-saving option would emerge, and congestion of major roads and freeways would reduce.
References
Allport, R., Brown, R., Glaister, S., & Travers, T. (2008, May). Success and failure in urban transport infrastructure projects. Retrieved from http://www.imperial.ac.uk/media/imperial-college/research-centres-and-groups/centre-for-transport-studies/Success-and-Failure-in-Urban-Transport-Infrastructure-Projects.pdf
Anderson, M. (2013, February). Subways, Strikes, and Slowdowns: The Impacts of Public Transit on Traffic Congestion. Retrieved from http://www.nber.org/papers/w18757
Beaudoin, J., & Lawell, C. C. (2017). The effects of urban public transit investment on traffic congestion and air quality. In H. Yaghoubi (Ed.), Urban Transport Systems (pp.111-123). Retrieved from http://doi.org/doi:10.5772/66834
Engebretsen, Ø, Christiansen, P., & Strand, A. (2017). Bergen light rail – Effects on travel behaviour. Journal of Transport Geography, 62(Supplement C), 111-121. http://doi.org.libezproxy.nait.ca/10.1016/j.jtrangeo.2017.05.013
Levy, J. I., Buonocore, J. J., & von Stackelberg, K. (2010). Evaluation of the public health impacts of traffic congestion: A health risk assessment. Environmental Health, 9(1), 65. http://doi.org/10.1186/1476-069X-9-65
Næss, P., Nicolaisen, M., & Strand, A. (2012). Traffic forecasts ignoring induced demand: A shaky fundament for cost-benefit analyses. European Journal of Transport and Infrastructure Research, 12(3), 291-309.
Newman, P., Kosonen, L., & Kenworthy, J. (2016). Theory of urban fabrics: Planning the walking, transit/public transport and automobile/motor car cities for reduced car dependency. TPR: Town Planning Review, 87(4), 428-458. http://doi.org/10.3828/tpr.2016.28
Schrank, D., Eisele, B., & Lomax, T. (2012). TTI's 2012 Urban Mobility Report. Retrieved from https://www.pagregion.com/Portals/0/documents/HumanServices/2012MobilityReport.pdf
SW, P. L. (Producer), & . (2009). The people's city: How Bogotá succeeded in reducing traffic congestion and smog. [Video/DVD] Films Media Group. Retrieved from https://fod-infobase-com.libezproxy.nait.ca/PortalPlaylists.aspx?wID=102714&xtid=43706
TransMilenio: renewing Bogota’s transport system. (2016, March 30). Retrieved from https://www.centreforpublicimpact.org/case-study/transmilenio/