TRAFFIC CONGESTION AND ITS ECONOMIC IMPACTS
CHAPTER TWO
LITERATURE REVIEW
2.1 Conceptual Review
2.1.1 Traffic Congestion
Joint Transport Research Centre (2007) of the Organization for Economic Cooperation and Development (OECD) and the European Conference of Ministers of Transport (ECMT) (2007), provided the following definitions of traffic congestion to reflect the different broad perspectives:
1. Congestion is a situation in which demand for road space exceeds supply.
2. Congestion is the impedance vehicles impose on each other, due to the speed-flow relationship, in conditions where the use of a transport system approaches capacity.
3. Congestion is essentially a relative phenomenon that is linked to the difference between the roadway system performance that users expect and how the system actually performs.
Road traffic congestion is an ever growing problem and global phenomenon of major cities throughout the world. Traffic congestion is a negative output of a transportation system which has many detrimental effects on the performance of the road network, the traffic flow, the society, the national economy and the environment. Congestion occurs in specific locations and propagates through network over time as congested conditions on a link spread to nearby links.
Many highways in Nigeria are bedeviled with traffic congestion which tends to defy various remedial measures adopted by different governments over the years. Journey times from one point to another, have remained unreliable and travelers have continued to face disturbing inconveniences in transportation (Popoola, Abiola and Adeniji, 2013). Aderamo (2012), examined traffic congestion problems and their causes at selected road intersections, in Ilorin, Nigeria. Traffic volume and delay were estimated and the causes of delay were identified. The result revealed that space and time variations exist in traffic flow and delays at the intersections. Traffic wardens and parking problems were found to be the greatest cause of delays. The study recommended that the road intersections be signalized and vehicle parking be strictly prohibited to reduce congestion and delays.
Ukpata and Etika, (2012), investigated traffic congestion which has become a common sight in most urban centres of Nigeria. A survey was conducted during the Annual National Conference of the Nigerian Society of Engineers (NSE) which held in December 2011 at the Calabar Tinapa Business and Leisure Resort. Three hundred (300) copies of questionnaires were distributed among participants and 196 returns were made and these were analyzed.The results showed that poor driving habits, poor road network, inadequate road capacity, and lack of parking facilities constitute the greatest causes of traffic congestion in Nigeria. Also, Lagos, Port Harcourt and Abuja were identified as cities most affected by traffic congestion.
Popoola, Abiola and Adeniji (2013) investigated the causes, effects and remedies of traffic congestion in Mowe/Ibafo section of the Lagos-Ibadan expressway. The result from the study showed the causes of traffic congestion as inadequate road capacity, poor road pavement, poor traffic management, poor drainage system poor driving habit, poor parking habit, poor design junctions/round-about, presence of heavy trucks, lack of pedestrian facilities, lack of road furniture, lack of parking facilities and others. Effects of road congestion from the study were waste of time, delay movement, stress, accident, and inability to forecast travel of time, fuel consumption, road rage, relocation, night driving, and environmental pollution. To drastically reduce these negative effects the following were proposed; there must be provision for adequate parking space, construction of proper drainage, enlarging the width of the road, rehabilitate all roads needing attention, public enlightenment, traffic education, hack down all illegal buildings/shops built on the right of way (ROW), creating a separate/alternative root for trucks and heavy vehicles, provision of pedestrian facilities, In-depth training of transport/traffic personnel, ban all form of road trading/hawking, and reduce the number of bus-stop are necessary.
Fadairo (2013) investigated traffic congestion in Akure, along Federal University of Technology Akure Road / Oja-Oba Road. The data collected from both primary and secondary sources were analyzed and these include using of camera to capture traffic congested zones; information on traffic-congested junctions; the roads and the land use areas; and traffic census for some selected road junctions in the study area. The results showed that poor driving habits, weather condition, absence of traffic light and/warden, work zones, road side parking, special events, lack of public mass transit, reluctance to use parking facilities and bus stops constitute the greatest causes of traffic congestion in the study area. The recommendations were that both Federal and State governments should initiate plans for the introduction of other forms of urban transportation such as metros and trains which support mass movement of people as done in major cities globally
2.1.2 Causes of Traffic Congestion
Different researches and reports have identified many interrelated factors that cause traffic congestion in developed and developing countries where the road network and road users behaviour are different (Cambridge Systematics, 2005; Kwon, Mauch and Varaiya, 2006) (Ukpata and Etika, 2012) also identified the main causes of traffic congestion in Nigeria as poor driving habits, poor road network, inadequate road capacity, and lack of parking facilities.
Bashiru and Waziri (2008) listed the causes of traffic congestion in Lagos to include the following: Presence of pot holes/bad road, trading activities along major roads, on-street parking, loading and discharging of passengers along major roads, illegal bus stops, flooding/poor drainage, vehicle breakdown, narrow road sections, religious activities, high volume of traffic, lack of parking space and lack of traffic light at some road intersections.
According to the European Conference of Ministers of Transport (ECMT) (2007), causes of congestion are numerous such as; too many vehicles, land use patterns, employment patterns, income levels, car ownership trend, infrastructure investment and regional economic dynamics. Chibuzor (2011), also identified the factors affecting vehicular traffic congestion based on five categories which are;
1. Societal / Public Causes
This is one of the subjectively classified problems that have to do with the society/public. Society/public induced problemsidentified under this category are wrong parking on traffic pavement, hawking on road pavement, dumping of refuse on road pavement, reckless driving, parking of heavy trucks on the roadway, vehicle breakdown, inexperienced drivers, illegal motor parks, too many vehicles sharing a road space, use of roadway for social activities, use of infrared emitter, improper turning, use of one carriage way, procession or demonstration, bumps, peak period congestion, and accidents.
2. Construction Causes
They are factors as a result of ill-construction managements, the factors identified under construction causes are; Lack of shoulder and lay-by, excess conflict points at intersections, inadequate channelization at intersection, use of long barrier median, lack of skid resistance surface, failed pavement, and closure of one lane during rehabilitation.
3. Design Causes
These are factors resulting from design incapability or inaccuracies and are identified as follows; small width of roadway, use of wrong curves, lack of well-defined traffic routes at intersections, lack of auxiliary lanes towards intersection, increase in volume of traffic etc. Sadi (1987).
4. Governmental Causes
These are problems emanating from careless governmental practices and administrations, some of these are police checkpoints, construction of one lane instead of two, lack of traffic signs and signals, badly located fuel stations, centralization of cities population, unplanned and uncoordinated development in metropolis, concentration of industrial establishment, absence of integrated traffic unit, lack of alterative travel route, indiscriminate use of siren, lack of street light, and too many schools along the road.
5. Natural Causes
These result from natural occurrences and climatic factors thus; Excessive rainfall, erosion, poor visibility due to bad weather, and potholes.
2.1.3Congestion’s Economic Impacts
Research on congestion’s economic consequences explores differences in regional or firm productivity, city growth and relocation responses by individuals and firms. The relationship between metropolitan economic activity and traffic congestion is complex and unclear (Taylor, 2002). Large regional economies lead to more congestion, while congestion may impede economic activities by degrading mobility services. Travel is a direct economic input which also leads to the congestion externality. In econometrics, this issue is called endogeneity and captures the methodological challenges of separating the competing benefits of big-city access and dense travel patterns from the drag of big-city road gridlock which raises travel costs or increases unreliability. Congestion reduces national (Fernald, 1999) and regional ( Boarnet, 1997; Hymel, 2009) economic competitiveness across regions, but firms and workers adapt within regions through location decisions and bearing commuting burdens (Cervero, 1996; Gordon et al., 1989). Thus, while congestion can potentially lead to travel and economic inefficiencies, it is unclear under what circumstances urbanisation benefits and adaptations by individuals, firms or through policy can no longer outweigh congestion’s potential drag (Sweet, 2011).
Intra-metropolitan studies of traffic congestion’s economic consequences suggest that it shapes regional geographies, but that it is unclear whether resident and firm adjustments can overcome the impact of congestion on urban function. According to the co-location hypothesis, congestion simply induces employer-employee suburban co-location (Crane and Chatman, 2003; Gordon et al., 1989; Levinson and Kumar, 1994). In contrast, empirical research on job–housing imbalance (Cervero, 1996; Cervero and Wu, 1998; Schwanen et al., 2004) suggests significant commuting burdens while theoretical urban economic models likewise imply congestion-induced urban economic inefficiencies (Arnott, 2007; Anas and Xu, 1999; Fujita and Thisse, 2002; Weisbrod, Vary, and Treyz, 2001), most notably by reducing agglomeration benefits (Graham, 2007). Moreover, research suggests industry-variant sensitivity to congestion’s potential drag—most notably, service industries are least sensitive while manufacturing industries are most sensitive, indicating that industry mix is important.
Inter-metropolitan area studies suggest that traffic congestion reduces regional competitiveness and redistributes economic activity by slowing growth in county gross output (Boarnet, 1997) or slowing metropolitan area employment growth (Hartgen and Fields, 2009; Hymel, 2009). Boarnet (1997) finds that congestion reduces productivity in California counties. Similarly, using panel data for major American metropolitan areas, Hymel (2009) finds that higher congestion leads to slower employment growth, but that its short-term job growth impacts are stronger than those over the longer term—implying regional adaptation. Thus, while intra-metropolitan studies suggest that firms and residents adapt to congestion, inter-metropolitan studies suggest that such adaptations may not overcome congestion’s regionally scaled drag.
2.1.4 Impacts of Traffic Congestion on the Economy
Some studies put forward that the relationship between transportation and productivity is vital as a well-established transportation system triggers a economic development (Lu et al., 2009). On the contrary, Eddington (2006) argued found that road congestion causes late arrival to workplaces, causing loss of output, missed deliveries, reduced productivity, and restricted economic growth. Choi et al. (2013) and Elisonguo (2013) stipulate that fuel consumption and depreciation of vehicles also tend to increase because of traffic congestion, thus leading commuters to spend more money on fuel. Businesses that have adopted the just-in-time system are more prone to be affected by traffic congestion as it is difficult to make just-in-time deliveries efficiently, thus reducing productivity and competitiveness (May and Marsden, 2010; Raheem et al., 2015). Choi et al. (2013) and Raheem et al. (2015) add that businesses dealing with perishable products rely a lot on travel reliability. However, travel conditions are unreliable when roads are congested, as traffic flow is impeded, thus causing travel time to increase.
An overwhelming body of literature has depicted that road congestion contributes to the aggravation of environmental conditions, including air pollution. Various authors have claimed that vehicular exhalations, triggered by traffic congestion, are the main causes of air pollution (Chakrabartty and Gupta, 2014; Elisonguo, 2013). Based on the data collected through the questionnaires, it was found that traffic congestion induces a high level of stress and frustration in commuters, especially drivers, as they are required to be more attentive and focused while driving in challenging conditions. The results obtained from the survey also revealed that accidents endanger the safety of commuters. Likewise, the survey conducted for this study generated results that depicted that commuters suffering from asthma or other respiratory problems may be prone to more serious diseases because of polluted air caused by vehicular exhalations.
2.2 Theoretical Framework
2.2.1 Three-phase traffic theory
Three-phase traffic theory is a theory of traffic flow developed by Boris Kerner between 1996 and 2002. It focuses mainly on the explanation of the physics of traffic breakdown and resulting congested traffic on highways. Kerner describes three phases of traffic, while the classical theories based on the fundamental diagram of traffic flow have two phases: free flow and congested traffic. Kerner’s theory divides congested traffic into two distinct phases, synchronized flow and wide moving jam, bringing the total number of phases to three;
Synchronized flow
Jam
Free flow (F)
Synchronized flow (S)
Wide moving jam (J)
The word "wide" is used even though it is the length of the traffic jam that is being referred to.
2.3 Empirical Review
Ogunbodede (2003) used Geographic Information System to investigate traffic congestion patterns in Akure and determine the management techniques suitable for their reduction. Topographical map of Akure as at 1966, Landsat images of Akure as at 1986 and 2002 were acquired and processed to produce the base map on which the major analyses were based. Major entities influencing traffic congestions were identified and modeled. The result showed two major ways by which GIS can provide solutions to traffic congestion in the area. The first way is the provision of traffic information that enables commuters and motorists to take rational decisions as to which route to take during peak hour travel. The second is the determination of appropriate queries that can evoke graphical response, which could be used to manage traffic congestions. The study also revealed that GIS is a veritable tool that can be used to sustain an endurable flow of traffic in urban environment, provided it is built on a properly designed database, which must also be amenable to constant updating. The study recommended that a GIS structure in addition to existing traffic management techniques should be put in place to monitor traffic congestions in the city.
Bashiru and Waziri (2008) studied the problems of intra-urban traffic in Lagos Nigeria and found that 57% of commuters and motorists spend between 30 to 60 minutes on the road due to traffic congestion. Their results also showed that the worst traffic congestion occurs on Mondays. They listed traffic congestion in Lagos to include, presence of pot holes/bad road, trading activities, on-street parking, loading and discharging of passengers, illegal bus stops, flooding/poor drainage, vehicle breakdown, narrow road sections, religious activities, high volume of traffic, lack of parking space and lack of traffic light at some road intersections.
Yusuf, Akpu, Arigbede and Abbas (2011), studied attitudinal factors of road users and increase commuting time in Zaria, Kaduna state. The data were collected from Zaria cityDanmagaji – Tudun Wada axis and Sabon-Gari, Kwangila-Samaru axis. The findings revealed that about 97 % of commuters attributed increased commuting time to the attitude of drivers among which are impatience and waiting for passengers, another 87% attributed it to passenger attitude. The study also showed that Zaria city-axis recorded longer commuting time than Samaru-axis. About 93% of respondents believed that commuting time is extended by 10-15 minutes, depending on the vehicles. The study revealed that delays in commuting time can be reduced through attitudinal change and sustained policy intervention.
Thwala et al, (2012), examined the effects and causes of traffic congestion in Ibadan city, Nigeria. The study was carried out in three neighborhoods (Agbowo, Bodija and Agodi Gate) in Ibadan North Local Government Area. Survey approach through questionnaire was used for data collection. Fifty (50) respondents were sampled in each of the three neighborhoods making a total of 150. Descriptive statistics such as means, simple percentages and graphics were employed in analyzing the data collected. Results show that 51.3% of the respondents spend between 21 minutes and above on congestion daily while 20.7% spend between 5-15 minutes and1.3% less 5 minutes. It was equally observed that residents in the city spend almost twice the time they would use on their trip from home to office due to traffic congestion. On the temporal and spatial pattern of traffic congestion in the three neighborhoods, the results revealed that Agbowo (65.3%) recorded the highest traffic congestion in the evening and morning period followed by Bodija (48 %) and Agodi Gate (31. 4%).On ranking of some major routes in the study area on traffic congestion by respondents, Agodi – Iwo Road route ranked highest with a mean value of 1.45 followed by University of Ibadan(U.I) – Bodija- Agodi Gate route with mean value of 1.27 and Sango- Iwo Road 1.03.The authors recommended the banning of street trading and provision of functional mass transit buses.
Ibrahim and Salisu (2012) studied the effects of road development on travel time and cost in Kaduna state, Nigeria. The researchdetermined the traveltime as itrelates to roadconnectivity and accessibilityamong some selected majorsettlements. Questionnaire administration was carried out in major motor parks in the selected settlements. The results of the study showed that there was significant decreasein travel timebetween different locationsin Kaduna Statewhich can beattributed to thehuge investments inroad development inthe State. Thereduction in traveltime has broughtabout greater spatialintegration in theState. It also revealed road development translated to improved accessibility and connectivity and decrease in travel time.