Some of the most important measures for the reduction of impact on environment are:
1. Technical Measures, for Reducing Atmospheric Pollution:
Technological improvements to road vehicles would seem to offer the greatest potential for reducing pollution in the short to medium term if there are no major changes to transport policy or individual behaviour. The three-way catalytic converter can reduce NOx, CO and HC by 95, 80 and 90 per cent respectively. Not surprisingly therefore, the fitting of these devices to new cars is now mandatory in many industrialised countries.
For all of these reasons, the catalytic converter cannot be regarded as anything like a full answer to the problem of pollution from the transport energy system. In some ways it actually makes matters worse, for it deludes people into thinking that it is some sort of magical technical fix that deals with all pollution, so that there is no need to change their behaviour in any way. It obscures the fact that the only way to deal with the problem properly, at source, is to burn less of the fuels or to reduce the amount of carbon in them.
Burning less of the fuels may be achieved in a number of ways. Changes to engines and power train, weight reduction and aerodynamic improvements are estimated to be capable of achieving a 28 per cent reduction in energy consumption by cars in the 1989-2010 periods in the UK. However, whether this potential becomes reality depends on manufactures’ attitudes and consumer preferences; judging by trends since the first energy shock of 1973, it would seem more likely that whatever technological improvements are made will be used to increase power and performance rather than to save fuel.
A second method of reducing energy consumption per vehicle is to encourage changes in driver behaviour. It is thought that driving smoothly could save up to 20 per cent of car fuel. However, motorists are frequently less interested in saving money than they are in saving time and many such as van drivers or users of company cars do not pay the loss of their wasteful driving practices. It would seem that behavioural changes are highly unlikely unless precipitated by legislation or by pricing mechanisms.
2. Alternative Fuels and Power Sources:
Rather than burning less fuel, another way of reducing C02 emissions is to develop alternative, low-carbon fuels to power road vehicles. Some are already in use, such as methanol, liquefied petroleum gas and electricity (batteries), whereas others such as compressed or liquefied hydrogen have yet to be fully exploited. However, most still face technical problems and volume or weight required on the vehicle. Moreover, as far as the longer-term issue of greenhouse gas emissions is concerned it does not appear that any of the alternatives fuel sources offer a clear advantage over petrol and diesel when the full fuel cycle is taken into account.
3. Reducing Total Emissions:
Increasing appreciation of the seriousness of these trends and of the growing contribution of road transport to global warming is leading to attempts to reduce carbon emissions per vehicle, but given the continuing rise in the number of vehicles and in the number of kilometres travelled by them, this can only be the staring-point. Longer-term goals must thus address the issue of total emissions rather than emissions per vehicle, as in the EU where there is a commitment to overall CO? Emission reduction, beginning with stabilisation of emissions by the year 2000. How this is to be achieved is unclear, particularly against the background of forecasts of increasing traffic of up to 140 per cent in the UK and 500 per cent in southern Europe.
4. Reduction of Noise Pollution:
A number of measures might be adopted under this heading:
1. Introducing technical measures such as the redesign of the engine for lower engine speeds; encapsulation of the engine and gearbox in a noise-absorbing tunnel or box; and modification of road surfaces to reduce tyre noise, though this may conflict with the aim of reducing skidding. Associated with this is the need to maintain road surface smoothness in order to minimise vibration.
2. Influencing driving habits to produce smoother flow and lower speeds and thus lower noise peaks.
3. Managing traffic to keep it flowing smoothly, perhaps by linking traffic lights to produce green waves of traffic and thus reduce stop-start progress.
4. Controlling motorcycles perhaps by preventing owner-modification, fitting better exhaust silencer or even controlling top speed and acceleration. As large motorcycles are really items of sports equipment rather than essential means of transport, there is no reason why they should be permitted to emit as much noise as fully laden commercial vehicles.
5. Lower rail noise can be achieved by shifting to electric traction, by better track maintenance and by modification of the rail vehicles, particularly the wheels and bogies. Vibration is reduced by much the same package. In the case of the Japanese Shinkansen lines, the use of iron girders has been minimised, vibration resistant track beds installed and rails polished to reduce corrugations. Even so, noise barriers have had to be erected, homeowners compensated or bought out and much of the line put in tunnels, up to 56 per cent of it on the Okayama-Hakata section. Among other measures, creation of buffer zone with plantation, construction of bypasses around towns and reduction of traffic may be useful.