Resarch areas

Three factors to combine to create what may be termed as a strategic decision-making and planning process are identified by researchers at VTI. The three factors can be summarized as long-term visions for the town’s development, long- and short-term actions, and public support for the long-term vision.

The way buildings are positioned relative to the design of traffic systems influences the public’s travel patterns and their choice of transport mode. It is therefore important that building layout and traffic are coordinated in order to create sustainable mobility. Sustainable mobility is an umbrella term for measures that reduce the number and length of car journeys and the need to travel at all. The aim of this study is to shed light on the conditions under which local authorities coordinate building development and traffic issues with respect to sustainable mobility.

This investigation is based upon a pair of case studies, and examines the handling of building and traffic issues during the planning of two residential areas, one in Lund and one in Trelleborg. The study analyses how coordination between these two areas has been influenced by, for example, political interest and public support for a more sustainable transport system, and the distribution of tasks and responsibilities within the local administration, as well as the methods used to achieve coordination and to create mutual understanding between politicians and officials.

The case study findings show that circumstances differ when it comes to the local authorities’ coordination of building and traffic issues. In Lund – with its public support for sustainable mobility, politicians’ and officials’ general agreement on longterm urban planning goals, workable planning structures, and mechanisms to achieve consensus between the parties concerned – conditions were favourable to coordination of public transport and building planning. In Trelleborg there was less coordination between traffic and building planning, which among other things resulted in less propitious conditions for public transport. One explanation for this is the fact that public transport did not have an obvious role to play in the realization of Trelleborg’s long-term development goals.

The results show that where coordination has worked, three factors have combined to create what may be termed a strategic decision-making and planning process. The three factors can be summarized as (i) long-term visions for the town’s development, (ii) long- and short-term actions, and (iii) public support for the long-term vision. The first factor concerns the way in which building and traffic issues relate to conceptions of future urban development. To achieve long-term climate and energy goals, such conceptions should be based on the principles of sustainable mobility. It is important that coordination is made a tool for the implementation of planning policy. The second factor concerns how the vision is turned into concrete, long-term and short-term actions. Politicians and officials must be in agreement if real influence is to be brought to bear on actual decision-making and planning processes. Swedish local authorities should therefore develop mechanisms to enhance mutual understanding between politicians and officials on the basic principles of sustainable mobility. This becomes especially important whenever it is necessary to change the underlying systems of thought that hinder greater coordination. In addition, the long-term vision for urban development should be clearly formulated in strategic plans, and the structure of those plans should form a framework that supports work on a variety of levels. The third factor concerns public support. Without public support it becomes hard to make the occasionally difficult political decisions that affect the public’s travel behaviour. Public support can also be a driving force behind the realization of political decisions.

The life cycle assessment methodology is used to describe the environmental impact and energy consumption of roads and pavements as well as the use of resources for road and pavement construction. Within a project at VTI, European life cycle assessment studies have been compiled.

The energy use due to transport is considerable, around 30 per cent of the total energy use in Europe. Road transport is responsible for a large part, more than 80 per cent, and since it is mainly fossil fuel that is used, the emission of greenhouse gases is substantial. Added to this is the energy used for building, operation and maintenance the infrastructure i.e. roads, railways etc. The infrastructure of roads is also an important factor, not only because of the environmental impact and resource use due to building and maintenance but also because of the effect it has on the fuel consumption of the vehicles due to road alignment and rolling resistance.

In this report a number of scientific studies using the life cycle assessment methodology to study roads and pavements are described shortly. The report is limited to European studies that can be considered the most relevant and that have been performed since the mid-1990s.

One conclusion of the compilation is that the results of these studies are not directly comparable since the underlying prerequisites differ. For instance they include different stages in the life cycle and also different aspects of the environmental impacts. Other differences are the design of road construction and the number of years for which the environmental impact is estimated. Another important difference is the focus of the studies. For example, some make comparisons of asphalt and concrete pavements, whereas other compare the alternatives either to deposit the waste materials, for example slag, or to use them in road construction.

A common result is the conclusion that all roads are unique and have their own specific conditions, which means that a flexible method is needed that can be adjusted to suite the road you want to study. Also, the studies that have in some way estimated the energy use due to traffic have concluded that the energy used for construction, operation and maintenance of the infrastructure only amounts to a small part of the energy use for traffic. A conclusion of this is that if the purpose is to make road transports more energy efficient it can be better to accept higher energy use for the infrastructure if it leads to lower fuel use of vehicles, since it can result in lower total energy use.

The Swedish diesel market is dominated by a fuel quality that differs in several aspects from the fuel quality that is used in the rest of Europe. The Swedish fuel quality was introduced in 1991 as a fuel designed to reduce both regulated and unregulated emissions compared to the standard European diesel. Since then the gap between Swedish fuel and the standard European fuel quality has diminished as the European diesel has improved. This study examines the remaining differences in exhaust emissions between the two fuel qualities, and values the difference in emissions using the official Swedish values for air pollutants in the transport sector.
Information on exhaust emissions from heavy duty diesel engines is taken from a literature study. The results show that the use of standard European diesel (EN590) instead of the Swedish fuel quality (MK1) gives rise to extra emissions of nitrogen oxides (NOx) to a value of 10–19 öre (1–2 eurocent) per liter diesel for heavy vehicles meeting Euro IV or V requirements. For vehicles meeting only Euro III requirements the extra emissions of nitrogen oxides are valued to 19–29 öre (2–3 eurocent) per liter diesel. EN590 also gives rise to more emissions of particulate matter (PM). The valuation of particulate matter depends on the size of the population living in the area where the vehicle is driven. For a heavy vehicle meeting Euro IV or V requirements driven in a small town like Laholm the extra emissions from EN590 is valued to a maximum of 5 öre (0,5 eurocent) while the extra emissions from the same vehicle driven in the inner city of Stockholm is valued up to 52 öre (5 eurocent) per liter diesel. For vehicles only meeting Euro III requirements the extra cost from EN590 is even larger.

Over time as old and dirty vehicles are replaced by new vehicles meeting harder emission requirements the advantage of MK1 over EN590 will diminish. For private cars the difference in emissions is also most probably smaller than between the heavy vehicles that are analyzed in this study due to lower emissions per liter diesel.

The tests used in the analysis are from the period 2003–2008 but the specification of MK1 has changed both in 2006 and 2011. The specification of MK1 is now closer to EN590 considering the distillation curve and density. New tests are needed to be able to conclude if this change in the specification of MK1 has had any effect on the emissions.

Dubbdäcksslitage av vägbeläggningar orsakar emissioner av inandningsbara partiklar (PM10) vars tillåtna halt i omgivningsluften är reglerad enligt en miljökvalitetsnorm. Ett sätt att minska partikelemissionen är att anpassa beläggningarnas egenskaper. Föreliggande projekt har undersökt betydelsen för partikelbildningen av inblandning av gummi från bildäck i två beläggningars bitumenfas. Undersökningen genomfördes i VTI:s provvägsmaskin där två gummiinblandade beläggningar av olika konstruktion (GAP11 och GAÖ11) och en referensbeläggning (ABS11) undersöktes. De bildade partiklarnas halter och storleksfördelningar studerades.

Resultaten visar att GAP11 ger upphov till 20–25 procent lägre halter av PM10 än referensbeläggningen, medan GAÖ11 inte skiljer sig från referensbeläggningen vad gäller PM10. Storleksfördelningar visar att partikelmassan för PM10 har två maxima vid 4–5 och 7–8 µm. GAP11 sänker koncentrationen av den finare moden jämfört med ABS11, medan GAÖ11 främst påverkar den grövre moden. Ultrafina partiklar bildas och en mod vid ca 20–30 nm dominerar partikelantalsfördelningarna. Dessa partiklar är relaterade till däckdubbarnas interaktion med beläggning och/eller däckgummi. Högre hastighet medför högre koncentrationer av ultrafina partiklar.

Sammantaget tyder resultaten på en sänkande effekt av PM10-emissionerna av gummiinblandning i konstruktionen GAP11, medan GAÖ11 inte verkar sänka emissionerna jämfört med en ABS11.

The main function of traffic lighting is to make the road and the road area safe for people. In order to reduce energy use and costs for traffic lighting it is imperative to have as energy-efficient lighting as possible while still maintaining the requirements for road lighting.

The objectives of this project are: (I) to provide basic data for various steps leading to the energy efficiency of road and street lighting network. (II) to examine how the use of dimming and various light sources affect visibility as experienced by people. The project used a relatively new method for measuring luminance based on digital photography. This new approach made it possible to compare the luminance of 18 different measurements where the lights had different power and source. Specifically, it included five test sites with ceramic metal halide (between 70–200 W), nine measurements of high-pressure sodium (35–250 W), two measurements of compact fluorescent lamps (42–100 W) and one measure each of the OLED (100 W), and LED (100 W).

This study shows that there is a potential to reduce the energy consumption of several of the existing road lightings by reducing power and still meet the requirements based on traffic safety, because the measured luminance and the illuminance show that some of the values fall between the recommended classes.

There is potential to save energy by adjusting the lighting after weather conditions and this could be exploited in a much higher level than it is today, especially in the northern part of Sweden. On roads with large variation in vehicle intensity there is high potential to reduce the lighting effect to lower luminance classes during periods when traffic flows are low, provided that individual assessment is made on a case by case basis.

This study highlights four different types of dimming schedules based on different conditions in which the savings in kWh/year are between 19–50 per cent. By applying different types of dimming schedules road lighting systems can be tailored to reach a very high degree of energy efficiency. In the future there are also opportunities to introduce synchronized reductions in road lighting and speed limits (so-called variable speed limits) to save energy but still maintain road safety.

Results from the web survey based on photographs from roads with various lighting show that most people thought that the visibility of a dark-dressed person was best in the maximum effect level for each light source (high pressure sodium and ceramic metal halide), whereas responses were not decisive regarding the best visibility between light sources. However, the survey shows that more people (from 62.4–71.6%) choose ceramic metal halide lighting instead of high-pressure sodium in order to feel most comfortable if they would be driving.

When the results were compared with another publication the power demand per km road was higher for most types of lighting we examined on 50 km/h roads in this study (they also have low pole height). Our results also show that a road with 150 W high pressure sodium lighting and power demand of 4.3 kW/km met the same MEW-class as a road with 100 W ceramic metal halide lighting. The difference is that the 150 W road had a 5 m wider spacing between the light poles.

In this study, we did not detect any significant differences between high-pressure sodium and ceramic metal halide on average luminance or illuminance levels. However, measurements of uniformity of luminance and illuminance of ceramic metal halide lamps were sometimes at higher levels compared to high pressure sodium lamps.