Transport problems in developed countries

Transport related environmental problems and congestion is of major concern for all the transport managing departments in almost all major cities of developed countries. With increasing awareness towards environment, coupled with its rapid degradation, has created serious challenges for the today’s transport planners and managers. In addition to this, transport safety and crash prevention has also remained a main focus for modern metropolitans.

2.2.1 The environmental impacts of vehicle travel

Car travel has a number of positive benefits, including increased mobility and freedom to travel. However, there are serious disadvantages to the motor vehicle including air pollution and contributing to greenhouse gases and global warming (Tyler Miller & Spoolman 2011). According to Corrales et al. (2000) there are five basic groups of transportation activities that adversely affect the environment, including the construction of transportation infrastructure such as roads, manufacturing of vehicles, vehicle travel, vehicle maintenance and disposal of used vehicles. The environmental impacts of vehicle travel include exhaust emissions, dust emissions from tyre wear on road surfaces, emissions of refrigeration agents for vehicle air conditioning, noise and safety in terms of accidents. Pollutants from motorised vehicles include nitrogen oxides and particulate matter. These pollutants present a two-stage problem with primary and secondary air pollutants. Primary air pollutants include, carbon monoxide, nitric oxide, benzene and particulate matter European Environment Agency (EEA: 2012).

Secondary pollutants include nitrogen dioxide and ozone, which is formed by the effects of sunlight on volatile organic compounds (Pearce 2000). Each of these pollutants damages human health, for example particulate matter is dust emitted from exhausts and is usually measured by diameter and expressed as PM10 which is the level of particulate matter with a

diameter of 10microns or less. Scientific evidence shows that high levels of PM10 can affect

the human respiratory system, cause long term damage to the heart and lungs and is potentially carcinogenic (Pearce 2000).

These pollutants can adversely affect human health and the environment affecting ecology and destroying ecosystems. The OECD (2011) state, that global greenhouse gas (GHG) emissions reached an all-time high of 30.6 gigatonnes (Gt) in 2010. It is estimated that these emissions will continue to increase by approximately 50% by 2050 unless national governments implement prevention policies. To put the problem in context, these predicted increases equate to an atmospheric concentration of GHG’s of an estimated 685 parts per million (ppm) CO2-equivalents by 2050, which is significantly greater than the concentration level of 450 ppm required to stabilise the climate at 2 degrees (2°C) global average temperature. The OECD (2011) and environmental experts warn that such high levels of GHG’s could potentially increase the global average temperature by 3 to 6o

C higher than pre- industrial levels before the end of this century, leading to significant changes in precipitation patterns, melting glaciers and rising sea-levels, with “catastrophic or irreversible outcomes for natural systems and society” (OECD 2011).

There have been significant advances in car technology, such as catalytic converters and lead free petrol engines, which have led to the reduction of exhaust emissions. However the European Environment Agency (EEA: 2012) maintain that the continuing growth in vehicle use and vehicle km/year mean that efforts to reduce emissions from individual vehicles are in danger of being overtaken by increases in the volume of traffic. According to Tyler Miller & Spoolman (2011) the USA is a prime example of a car centred country. The country contains 4% of the world’s population with an estimated one third of the world’s private cars and commercial vehicles. The country has developed with dispersed cities and urban sprawl. Passenger vehicles are used for 98% of travel needs, with an estimated three quarters of the working population driving to work in single occupancy each day. These travel patterns mean that the USA is responsible for an estimated 43% of the world’s total vehicle fuel consumption. Statistics released by the Department of Transport in the UK, indicate that the

number of vehicles in the UK is increasing from an estimated 4 million in 1950 to 34 million in 2010, equating to an annual growth of 3.7%. The proportion of households with access to a motor vehicle has increased from 14 per cent in 1951 to 75 per cent in 2010. There is also evidence that the average annual mileage of four-wheeled cars is falling from an estimated 9,700 miles in 1995/97 to 8,430 in 2010 (Department of Transport 2012). According to the Department for Transport (DfT 2011), transport makes up 21% of all United Kingdom’s domestic carbon emissions.

National governments are committed to reducing greenhouse gas emissions and one of the key target areas is reducing emissions from road vehicles. In order to do most transport policies need to implement traffic demand measures, which will encourage a modal shift away from the private car and towards greater use of public transport and non-motorised modes such as cycling and walking. In order for these policies to be effective Chatterjee & Venigalla (nd.:p.1) point out that the transportation planning and management of travel demand must have a thorough understanding of travel patterns and existing problems before carrying out policy changes. This requires detailed data on existing travel patterns, with traffic volumes and forecasts for predicted traffic volumes and pollution emissions from that traffic to be determined. Once the extent of the problem is realised only then can planners and policy makers implement strategic policies to address the issue. The remainder of this literature review will focus on travel demand management and specific examples of traffic demand management schemes.