The use of digital maps for the evaluation and improvement of a bicycle-network and infrastructure

Een duurzaam mobiliteitsbeleid gaat gepaard met het stimuleren van fietsgebruik. Potentiële fietsers haken echter vaak af omdat de veiligheid en het rijcomfort van fietspaden langs de Vlaamse wegen te wensen over laat. Een oplossing om de veiligheid van fietspaden te verhogen, is het optimaliseren van de kwaliteit van de fietsinfrastructuur langsheen een fietsroutenetwerk. Rekening houdend met de omvang van zo’n fietsroutenetwerk, is het essentieel om te bepalen op welke locaties de nood aan een verbetering van de infrastructuur van prioritair belang is. In dit artikel wordt een methodologie voorgesteld voor de evaluatie van de fietspadeninfrastructuur en het detecteren van de ernst van knelpunten langsheen het fietsroutenetwerk. De ontwikkelde methodologie berekent de knelpunten in het netwerk aan de hand van een Geografisch Informatie Systeem (GIS). De knelpunten worden bepaald door de afwijking te berekenen van de bestaande fietsinfrastructuur ten opzichte van een vereiste - en dus veiligere - infrastructuur. Als toetsingscriteria werd het Vademecum Fietsvoorziening, een document van de Vlaamse overheid, gebruikt. Dit vademecum beschrijft de vereiste fietsinfrastructuur afhankelijk van karakteristieken van de aanliggende weg. Een eerste stap is het selecteren van alle relevante criteria die bepalend zijn voor de veiligheid van het fietspad. Vervolgens wordt een inventaris opgesteld van alle attributen langsheen het wegennetwerk. Elk attribuut (bijv. de breedte van het fietspad) wordt geëvalueerd een draagt geheel of gedeeltelijke bij tot de ernst van een knelpunt. Aan de hand van een multi-criteria analyse wordt een knelpuntenscore berekend voor elk stuk fietspad in het netwerk. De resultaten worden gevisualiseerd op een kaart. Dit onderzoek kadert binnen het mobiliteitsbeleid van de stad Gent, en is een deel van een prioriteitenkaart die aanduid welke fietspaden als eerste dienen (her)aangelegd te worden

Flexible and stretchable circuit technologies for space applications

Flexible and stretchable circuit technologies offer reduced volume and weight, increased electrical performance, larger design freedom and improved interconnect reliability. All of these advantages are appealing for space applications. In this paper, two example technologies, the ultra-thin chip package (UTCP) and stretchable moulded interconnect (SMI), are described. The UTCP technology results in a 60 µm thick chip package, including the embedding of a 20 µm thick chip, laser or protolithic via definition to the chip contacts and application of fan out metallization. Imec’s stretchable interconnect technology is inspired by conventional rigid and flexible printed circuit board (PCB) technology. Stretchable interconnects are realized by copper meanders supported by a flexible material e.g. polyimide. Elastic materials, predominantly silicone rubbers, are used to embed the conductors and the components, thus serving as circuit carrier. The possible advantages of these technologies with respect to space applications are discussed

Embedded passive components for improved power plane decoupling

In this paper, a detailed power integrity study is described that compares the behavior of surface-mount devices and embedded components for power decoupling. Through measurements and simulations, it is found that when the layer count of the board is low, there is no significant difference between both technologies. When the number of layers increases, the short connection for the embedded components is clearly superior to the surface-mount capacitor. The resonance frequencies for the embedded capacitor do not change significantly with the increased layer count. The case with the surface-mount capacitor however, shows a large increase in parasitic inductance due to the long vias through the board

A dual-mass capacitive-readout accelerometer operated near pull-in

A mechanical two-mass configuration and a readout circuit for a single-axis capacitive-readout accelerometer with ΣΔ force-feedback is presented. The system reduces electrical and quantisation input-referred noise through the use of negative springs, reduced gaps in the readout capacitors and maximised readout voltage. A theoretical analysis and simulation results are discussed

Mechanical analysis of encapsulated metal interconnects under transversal load

Novel insights regarding the ability of encapsulated metal interconnections to deform due to bending are presented. Encapsulated metal interconnections are used as electric conductor or measurement system within a wide range of applications fields, e.g. biomedical, wearable, textile applications. Nevertheless the mechanical analysis remains limited to reliability investigation of these configurations. Different papers and research groups claim that meander-shaped metal interconnections are predisposed for these applications fields due to their deformability while, to the author’s knowledge, no reports are found about this ability. An analysis based on the work needed to bend interconnections to a certain curvature will be used to compare different interconnection configurations with each other. The experimental as well as the simulation setup is based on PDMS encapsulated PI-enhanced Cu tracks. The results and conclusions are specific for this type of interconnections, but can be extended to a global conclusion about stretchable interconnections. From the obtained insights it is proven that periodically meander-shaped interconnections need significant less work, up to more than 10 times less, to bend the interconnection to the same curvature compared to straight interconnection lines. Furthermore it shows out, for the meander-shaped interconnection, that per increase of 250µm encapsulation thickness the work raises with a factor 2. For straight interconnection lines the work in function of the encapsulation thickness is limited to 20%/250µm. The bendability of the straight interconnection lines is determined by the shape of the interconnection, where for meandered tracks the encapsulation will determine this factor, for an encapsulation thickness of maximum 1mm. For encapsulations > 1mm, the encapsulation thickness will become the predominant factor which determines the deformability for both interconnection shapes

ITS-technieken om verkeersveiligheid te verhogen op kruispunten met verkeerslichten (VRI’s): Onderzoek naar de mogelijkheden van dynamisch snelheidsadvies op VRI’s

This report proceeds on the report “ITS and traffic safety, Intelligent Transport Systems” (RA-MOW-2008-007) and expands on the possibilities of ITS systems for the enhancement of traffic safety around intersections equipped with traffic lights. It seems quite obvious that there is a higher risk for traffic accidents at junctions then on other road segments, since road users cross at junctions. Based on accident statistics, this report proves that enhancing safety around intersections indeed has a strong positive impact on the global traffic safety. It also introduces the use of Intelligent Transport Systems (ITS) as a mean to enhance safety around crossroads equipped with traffic lights. A detailed technical description is given of the communication techniques supporting such systems, and an extensive overview is given of the state-of-the-art in the most relevant related research projects. Accident statistics prove that an important portion of both fatal and non-fatal accidents occur at intersections. In the EU-13 this represents 5.476 casualties or 21.3% of all traffic casualties. In Belgium 19.3% of all traffic casualties are the consequence of incidents at intersections. When the absolute figures are divided per million inhabitants, Belgium has the fifth highest number of deaths at intersections in Europe (after Italy, Hungary, Estonia and Poland). This Belgian number, 20 lethal accidents per million inhabitants, is higher then the average EU-13 (18.1) and EU-16 (19) numbers. In the Intersafe project (performed within the PReVENT project) several accident scenarios where studied, and among others the percentage of intersection fatalities within the total of traffic casualties were determined for France, Great-Brittan and Germany. Junctions are responsible for 30 to 60% of the incidents with wounded, and 16 to 36% of the fatal incidents. When examining the analyses of red light negation, it can be concluded that the critical situation can be avoided if the driver is informed and warned earlier. However, it has to be guaranteed that this information and warnings do not lead to an even more dangerous risky behaviour where they are interpreted as “if I drive faster I will be able to just catch the green light”. This would create an even higher risk of serious accidents, therefore enough attention should be given to this issue. The above numbers and analyses prove that enhancing safety around intersections should be a priority in traffic policy. Extra attention should be given to preventing red light negation, since this is a major part of the dangerous traffic violations. Research focusing on accidents on intersections proved that there is a connection between the type of intersection and the degree of traffic safety on that junction. A study was found that provides a quantitative evaluation of traffic safety around different types of intersections, expressed as the number of registered incidents with wounded per million passing vehicles. This number is the highest for intersections with traffic lights (0.11), followed by junctions on a main road (0.09), junctions with right of way (0.09), roundabouts (0.07) and junctions without right of way (0.06). The average number of wounded per accident decrease in the following order: traffic lights, main road, right of way, no right of way (respectively 1.22, 1.18, 1.11, 1.09). The seriousness of accidents, expressed as the number of hospitalizations rather increases in that order (respectively 17,16,18,18). This means that rearranging intersections can be beneficial. An American study investigated what the effect would be if the junctions in North Virginia were rearranged. It was concluded that delays would be lowered with 62 to 74 % (according to junction type), meaning a reduction of 300.000 lost hours per year. The annual saving in fuel consumption would be 200.000 gallons (757.000 litres). Traffic safety would increase drastically: reforming junctions into roundabouts would result in 62 less accidents and 42 less wounded (comparison between 1993 en 2003 with five crossroads for which accident statistics were available). Therefore a logical measure to enhance traffic safety is to rearrange intersections equipped with traffic lights or to transform them into roundabouts. Other possible measures can be related to traffic lights regulation, road layout (canalization, slopes, facilities for vulnerable road users, etc), improvement of visibility, driving education, speed management around intersections, enforcement (camera’s), road surface, etc. These measures are already applied in Flanders today. But a technique that is almost entirely neglected is the employment of Intelligent Transport Systems to increase traffic safety around intersections. This approach is further elaborated in this report. When traffic control infrastructure at crossroads is extended with intelligent software and possibly sensors and means to communicate with neighbouring vehicles, applications can be developed with a positive impact on different domains. The three most important ones are traffic safety, traffic circulation and the environment. Many studies focusing on intelligent intersections aim to enhance traffic circulation. Self-organizing traffic lights divide traffic into platoons by counting (e.g. using counter loops in the road surface) the number of vehicles waiting at the traffic lights, and adjusting the switching times accordingly. This technique was applied in a traffic simulator to the Wetstraat in Brussels, where it would lower the total travel times approximately 25%. In other research a system was developed where every vehicle can vote for switching of the lights. For this it communicates it’s identity, direction, position and place in the queue to the traffic light. Using this information of all the neighbouring vehicles, the light can calculate which light switch will result into the greatest total profit for all vehicles. Results showed an enhancement in average waiting times from 30 to 50%. In the domain of positive effects on traffic safety, developments are taking place in a number of European research projects such as PReVENT, Safespot and VII. Frequent scenarios that are being tackled are avoiding of or warning for red light negation, avoiding accidents with vulnerable road users and coordination of turning left with oncoming traffic. Also, applications that aim for an enhancement in traffic circulation imply an enhancement in traffic safety. Less research can be found aiming at environmental benefits, but again applications focusing on enhancement of traffic circulation imply positive effects on the environment. A common aspect of many of these applications is the fact that they rely on communication technology. This can be divided into three major groups: local short-range communication, cellular data networks and digital broadcast technologies. When they are studied in the scope of intelligent intersection control, then both broadcast- and cellular technologies do not qualify as a possible supporting technology. This because of the one-way communication character of broadcasting, and the higher delays and end user cost of cellular data networks. This limits the choice to local communication media, more specific CEN DSRC, IEEE 802.11p, CALM-M5, CALM-IR and IEEE 802.15.4. When taking a closer look at their parameters, they indeed seem to be very suitable: they are interactive, free to use, can offer a high bandwidth and are not dependent of network operator coverage. An extensive technical description of these communication technologies is given in this report. CEN DSRC is typically used for Electronic Toll Collect (such as Télépéage in France). However it is not suitable for the implementation of intelligent traffic lights because it only supports one-way communication. IEEE 802.11p is an amendment to the well-known IEEE 802.11 Wireless LAN technology (also known under the Wi-Fi hallmark) for use in vehicular environments. This technology is also not suitable for intelligent traffic lights in Flanders since it operates on the ITS frequency bands of the US. CALM-M5 however is the European derivate of IEEE 802.11p, and this technology indeed is greatly suitable. But just like IEEE 802.11p it will suffer van scalability issues, meaning that more research regarding scalable routing protocols has to be conducted before it can be used in a real rollout. In the field of directional communication both European standards CALM-IR and CALM-MM qualify as an implementation candidate. CALM-IR is a communication standard based on infrared light, en is very good in sharply defining communication zones. CALM-MM operates on frequencies similar to radar, and can provide very high bandwidths. On short to medium term CALM-IR has the advantage that it is already much further developed then CALM-MM. IEEE 802.15.4 is a communication technology used in wireless sensor networks. Its main characteristics are energy efficiency and scalability. This technology is most suited for application in mobile devices, thus for including vulnerable road users in the intelligent intersection. However this requires that the (typically SANET) routing protocols on top of this technology support mobility. This demands further research. To conclude, on short to medium term three communication technologies qualify for the implementation of intelligent traffic lights: CALM-M5, CALM-IR and IEEE 802.15.4. CALM-M5 is suitable for omnidirectional communication with vehicles, CALM-IR for directional communication with vehicles and IEEE 802.15.4 for omnidirectional communication with vulnerable road users. Further research is needed regarding suitable routing protocols before CALM-M5 and IEEE 802.15.4 can be successfully applied in intelligent intersections. Based on these technological developments, several research projects already investigate intelligent intersections. INTERSAFE is a subproject of the PReVENT project. Goal is to inform and/or warn the driver about traffic lights; this information/warning contains information regarding the time and the proper speed to safely cross or exit the intersection. The idea is to avoid conflicts at junctions with these information/warnings. These conflicts can be caused by absent-mindedness (not noticing the traffic light or the state of the lights), by maladjusted driving behaviour in function of the expected red- or green cycle, or by an inadequate insight in the traffic lights installation. Finally, it is expected that this information/warning will stimulate the driver to adjust his driving behaviour, reducing the risk for conflicts. This adjustment of the driving behaviour mainly is related to a decrease in speed, this can be performed gradually, but can bend to severe braking if the information/warning is not taken into account on time. Two demonstration vehicles were designed for testing this technique. A visual and auditive warning was used to give speed advice. Complying with this speed implies that the intersection can be safely crossed. Demonstrations at Versailles proved that this systems works well on the test roads from a technical point of view. However, the nature of the provided information and the voluntary character of the system imply that the safety on these intelligent intersections is highly dependent of they way the driver translates the information/warning into adjusted driving behaviour. From this research project, it appears that if some specific technical enhancements are conducted, supporting driving behaviour at intersections can improve traffic safety. IRIS is a sub-project of the Safespot project. IRIS uses vehicle-infrastructure communication to analyze the movements of all individual vehicles, and laser scanners to identify vulnerable road users. Based on these inputs, the system can assess dangerous situations on time and take necessary measures to avoid accidents (such as adjusting switching times of the lights or sending warning messages to human-machine interfaces in the vehicles using wireless communication). The IRIS system focuses on three scenarios responsible for a major part of the accidents at intersections: red light negation, turning left (conflict with oncoming traffic) and turning right (conflict with vulnerable road users). In the project experiments are performed in a driving simulator. Simulation makes it possible to perform a more systematic and extensive analysis of the applications and their possible variations. Early during development simulation can be useful to study the timing of the applications, derive optimal parameter settings and assess the potential impact of the applications if validation in the real world is not possible. In parallel with the simulation work, a real IRIS system is built and tested in the project. In May 2009 a first public demonstration of this system will be given Helmond, The Netherlands. Aiming to improve traffic circulation and to reduce consumption and emissions, the project Tovergroen was set up in The Netherlands. Tovergroen is a system to detect trucks and give them priority if possible by prolonging their green phase. However, the detection system performed inadequate, not recognizing trucks or recognizing the wrong vehicles as trucks (campers, cars with trailers, etc). Despites these problems Tovergroen increases the chance that trucks do not have to stop with 5 to 10%. Tovergroen decreases red light negation of heavy traffic with approximately 30%. It is expected that the positive effect will be even greater using a more reliable detection system. In cooperation with the Technical University of Munich, Inglostadt en GEVAS software, Audi has developed Travolution. Aim is to inform drivers regarding the appropriate speed to maintain to cross the intersection without stopping. Using wireless communication, the intelligent traffic light sends the duration of the red light to the in-vehicle system. The in-vehicle system then calculates the appropriate speed to catch the green light and informs the driver. In Inglostadt 46 intersections were equipped with this system, and two test vehicles were used. In the next phase, this experiment will be extended with 20 cars and an additional 50 intersections. Goal is to investigate how the optimization of traffic light controllers in urban areas can decrease pollution and travel times. At the ITS World congress in New York, several other applications were demonstrated where information is communicated from traffic lights to vehicles. Although there is almost no information available regarding these demonstrated applications, a short description is included in this report

Homogeniseren van snelheden in Vlaanderen: een verkennend onderzoek (Verkeersbordendatabank): onderzoek naar mogelijkheden om de verscheidenheid in snelheidszones te reduceren zonder dat de verkeersveiligheid en de verkeersleefbaarheid worden geschaad

The aim of this research is to investigate whether the database “Road signs” could be used to homogenise speed regimes. It also examines what the effects of homogenised speed zones could be on the number of road signs. Driving speed is an important factor in road safety. Speed not only affects the severity of a crash, but is also related to the risk of being involved in a crash. The speed is not only a quality criterion within a transport system but should also take into account the need for structural safety margins. A human as the vulnerable road user is the weakest element in the road traffic system. This vulnerability explains the injury in an accident. The vulnerability is in relationship with the purely biomechanical properties of the human being, the speed-related released kinetic energy in a collision and the characteristics of the vehicle. The number of accidents depends heavily of the varying conditions in traffic and environment. Flanders, with its fragmented space and his historically not very well planned underlying road network, is characterised by strong changes in road structure and environment. Most research reports conclude that speed differences at road section level (larger speed variance) is related to higher crash rate. However, - taking into account these varying characteristics - the number of changes of the speed limit on a road has to be kept as limited as possible. Changes in the speed limit and differences of speed in the traffic flow and speed differences between different vehicles increase the risk of accidents. Larger differences in speed between vehicles are related to a higher crash rate. Without exception, a vehicle that moved (much) faster than other traffic around it, could have a higher crash rate. There is also – mainly because of the limitations of the capacity of the road user –a need to simplify the traffic tasks. Homogeneity in the traffic flows is needed. If this is translated to the characteristics of the vehicle, the mass and speed of the vehicle along with the directions in which the traffic participants move, determine the degree of homogeneity. Through greater homogeneity, one can reduce the possibility of conflict: how more homogeneous the traffic is, how limited the chances of a conflict/ accident. After outlining the legal framework, the theoretical framework -within the categorisation of roads and within the possible environmental factors- that may determine the speed regimes, is situated. In Belgium apart from vehicle related speed, the road administrator makes specific speed regulations related to the categorisation of the road. Whether the existing general maximum speed (90 km/h) should be changed in to lower general speed level (70 km/h) should be framed within the safety goals and within driving comfort and an acceptable traffic flow. To achieve these goals a homogenizing of the speed regimes could be a solution. In seven cases (chosen within a spatial framework), the effect of lowering the overall speed of 90 to 70 km/h is examined. Here the length of the road segments where the maximum speed changes and the chosen speed within a specific road categorisation is described. Although the application of these generic scenarios (more effect of the application of the zone boards can be expec-ted) on the database (road signs) are only a first analysis, the result on the number of speed signs, is important. The conclusion is that reducing the speed from 90 to 70 km/h, 6 on 7 speed signs can be removed. Less speed signs reduce the needed attention and the workload for the driver; more smoother and safer traffic could be the result