Travel trips and choice, and freight volume and modal choice can be affected by several factors such as urban density, transport infrastructure and the design of transport systems. Recent major innovations in infrastructure design such as linking urban transport to land-use patterns, zoning, increase access to jobs and shops, comprehensive and integrated planning strategies have lead to reduction of urban pollution with possible climate change benefits as they reduce the reliance on car (Newman and Kenworthy, 1989). Designing clusters under the mixed land model, where homes, jobs and stores are together reduces the trips significantly (ECMT/OECD, 1995). However, designing infrastructure to suit transport demands is difficult because of the multiple needs of the different transport modes. Also, an integrated strategy requires coordination between many stakeholders which is not always easy (Gakenheimer, 1993).
Traffic and fleet management aimed at reducing road congestion and increasing traffic flows for different modes is gaining prominence because energy savings up to 10% in urban areas can be achieved, resulting in reduction of GHG emissions. Advanced Traffic Control Systems (ATCS), which include well-designed and coordinated control systems, have led to improvements in many cities of developed countries such as Cambridge in UK, and Oslo and Bergen in Norway (OECD, 1995). Singapore is one of the few countries that have instituted several demand management measures aimed at reducing demand for cars and restraining car use. These include fitting smart cards on vehicles as a means of paying tolls and use of road sensors (Pezoa, 1995), vehicle quota system based on traffic and electronic road pricing to reduce traffic jams in peak hours (Ang, 1996a) and the area licensing scheme that is continuously being reviewed (Ang, 1996b; see Box 8.3). Modal shifts from road to rail can yield energy savings of 0-50% resulting in GHG reductions and even higher in non-fossil fuel electricity powered electric trains, but these savings vary among regions and current trends of moving from rail to road travel can negate such benefits.
|Box 8.3 Urban transport demand management: a case study of Singapore (Source: Ang, 1993; Ang, 1995; Ang, 1996 A and B; Singapore Land Transport Authority, 1996)|
|Many cities in fast developing countries are adversely affected
by serious traffic congestion leading to increased travel time and fuel
consumption, environmental degradation and productivity losses. Singapore
is one of the few countries in the world that has adopted measures to moderate
demand for cars and to restrain their use.
Singapore, a small and densely populated state, has being going through rapid economic development in the past 30 years resulting in significant increases in road transportation. The country embarked on land transport policy with technical, regulatory and policy measures to control transport growth. A recent white paper on transportation clearly identified two demand management measures that are aimed at reducing demand and use of cars. These are a vehicle quota system and a road pricing system.
The vehicle quota system (VQS) was introduced in May 1, 1990 after several fiscal measures such as import duties, registration fees, and road taxes had been tried with very little success. As an example, purchase price of new cars increased by almost 200% in real terms between 1974 and 1990, but the car population doubled in the same period. Rising incomes was believed to have accounted for this growth and there was no indication that it will slow down by further increase in taxes. Hence, the VQS was designed to link vehicle population to road capacity. Vehicle registration is fixed by the government based on current traffic conditions and the market determines the vehicle price. It was applied to all vehicles except scheduled buses and school buses. New vehicles are put on a tender that is held in specific periods and cars can be used for a limited time without further taxes. Although the system is constantly under review to reduce its weaknesses, some changes have been achieved as shown in Table below.
|Table Annual Average Growth Rates of Road Vehicles during the introduction of VSQ|
|Other road vehicles||2.2%||1.4%|
|All road vehicles||3.9%||3.1%|
|The Area Licensing Scheme (ALS) was introduced in 1975 to
reduce traffic congestion in designated restricted zones in the city centre
during peak hours. The scheme included components such as car-pooling and
park-and-ride for weekdays. Special public buses for commuters and car parks
were introduced for commuters, Area licenses were made available in convenient
public outlets, and compliance was enforced. As a result of this scheme,
the number of vehicles entering the restricted areas fell by a third and
cars by 61%. In addition, commuters changed trip times and modal shift was
observed with car owners moving to buses. Noise and air pollution was also
reduced. Between 1975 and 1989, employment in the restricted zones grew
by a third in size. With the introduction of the rail-based Rapid Transit,
all vehicles had to pay ALS fees except public buses, motorcycles and essential
vehicles; car pool exemption was banned; and evening ALS was introduced.
Also in 1994, a whole ALS system was introduced that led to a reduction
of traffic by about 9% and increase in traffic speed.
The Electronic Road Pricing (ERP) system was introduced to replace the ALS, which was a manual pricing system that had limited coverage after a lengthy process of design and evaluation, as this was the first such system in the world. In 1993, the government offered three multinational consortia to develop a prototype, which they did for about a year. After modifications and improvements on the designs, the ERP started in late 1997. The system uses a smart card that is slotted into a unit attached to the windscreen. A detector automatically deducts charges when a gantry is crossed. Vehicles without cards or with cards of insufficient value are photo-recorded. These cards can also be used for phone calls and supermarket purchases.
On the whole, no doubt thanks to the introduction of these systems, Singapore car ownership is 11 per 100 people, which is very low compared with other countries with the same economic output. In 1995, the average road transport fuel consumption was 0.34 tonne of oil equivalent per capita resulting in 0.29 tonne of carbon emission per capita which is also low in comparison. Also, over 80% of the cars are less than 1600 cc and are well maintained, with an efficiency of 9 litres of gasoline per 100 km.
Increasing occupancy of travel trips by promoting mass public transport systems can result in substantial energy savings and GHG reductions because the emissions per passenger are lower especially with well organised routing and stops. Energy efficiencies in passenger-km for such systems can be up to 4 times better than private cars (Hilling, 1996). Potential reduction in emissions from using such systems in comparison to personal transport can be up to 99% in HC, 97% in CO, 85% in NOx, 46% in SOx, and 27% in PM (Hilling, 1996). Also, public transport systems especially well co-ordinated bus systems can prove very effective as shown in the case of Curitiba (see Box 8.4). Urban rail systems can prove beneficial in reduction of GHG emissions but experience shows that they are expensive especially for cities with less than 5 million people. The number of tracks also seriously affects its viability (PTRC, 1991)
|Box 8.4 Curitiba's public bus system (Source: Rabinovitch and Leitman., 1996)|
Curitiba, a Brazilian city of 1.6 million people, underwent a major restructuring of its bus system in order to reduce congestion and save journey time. This restructuring is a good example of the integration of transport with land-use planning. The main features of restructuring are the reserved bus lanes, the priority of buses over other models at intersections, a hierarchy of frequency, interconnecting routes, an easy ticketing system to avoid time wastage, and shelters at bus stops. Besides those features, various innovations, such as level boarding tubes, assure the speed of bus loading and unloading, therefore allowing the buses to operate like a surface subway. Feeder buses provide services to the five main corridors from more outlying areas. As a result, the use of buses in Curitiba has increased significantly.
Meanwhile, three factors made Curitiba a unique case: 1) a continued local policy, supported for many years, and favourable to the use of a public transport; 2) an urban plan compatible to the solution of public transport; and finally 3) an implementation of an integrated net transport.
The implementation of the integrated net was facilitated mainly by the interest of the Volvo Manufacturing Company, which was already established in that region, and the geographic characteristics of the city that allow the elaboration of an urban plan suitable to the net.
The rationalisation of the integrated transport system, the land-use legislation, and the fact of meeting human needs were seen as the driving forces for this system. However, this system is yet to be repeated elsewhere.
With a well-developed communication system, use of telephones and telecommuting can assist to reduce travel trips leading to reduction in GHG emissions (Davidson, 1994). As satellite-based communication systems develops, more comprehensive routing of different modes will be possible leading to reduction in GHG emissions. More details are available in Table 8.5. However, these options can be expensive.
|Table 8.5 Technical and potential transport productivity options|
|TECHNOLOGY||EXAMPLES||STATUS||TECHNICAL FEASIBILITY||CONVERSION EFFICIENCY||ENVIRONMENTAL IMPACT||MARKET POTENTIAL TIME FRAME|
|1. Traffic Control||
Road information systems
High occupancy vehicles
Interactive signals and controls deployed
Interactive signals and controls feasible
High occupancy vehicle
Significant local gains with the elimination of stop & go traffic (>10%)
Increased capacity of highways
Major pollutant reduction (30-50%) at local sites
Reduction of emissions in proportion to efficiency gains
|2. Travel Substitution||
Telecommuting in trials
High occupancy vehicle programmes
Electronics use expanding rapidly
|Dependent on modal shift of transport market and flexibility of work arrangements||
Move to more efficient energy conversion modes
Higher overall transport productivity (10-30% possible)
Reduction of emissions and change of emission sources
Reduction potential is approximately the same as fuel reductions
|3. Route Planning||
On-board navigation systems
Electronic displays and interactive warning
Satellite-based communication positioning systems in marine/air use
Demonstration on highway
On-board maps and interactive reporting
Anti-congestion measures feasible
Advanced communication technology
Staggered work hours
|Gains depend upon interaction between vehicle and overall road transport system||
Reduction of emissions and change of emission sources
Reduction potential is approximately the same as energy reductions
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