DYNAMIC SPEED ADAPTATION IN ADVERSE CONDITIONS

This paper proposes a system for dynamic speed adaptation in adverse conditions, such as wet/slippery roads, decreased visibility, darkness and sharp curves. Accident risks increase drastically in such conditions, especially since drivers often do not adapt speeds to lower friction or impaired visibility. Thus, the discussion is centred around a method for calculating the appropriate highest speeds and a system to influence driver’s speed-choice in these conditions via an in-vehicle device. The safety effect of the proposed system is estimated to result in a 19% - 42% reduction of injury accidents in Sweden. The paper concludes by making suggestions for further research into alternative technological solutions, effects on driver behaviour and workload and implementation of the system for other reasons than weather and road-dependent adverse conditions. (Less) Document type: Articl

SPEED REGULATION BY IN-CAR ACTIVE ACCELERATOR PEDAL

The effects on speeds and speed distribution were studied in a large scale field trial with an in car system for speed adaptation in the city of Lund, Sweden. In the trial 290 vehicles were equipped with an "active accelerator pedal" and data logger for a period of 3-11 months. Data was logged in each test vehicle during the whole trial and was analyzed for 3 one-month periods: Before activating the system, after short time use and after long time use. The results showed significant reductions in the speed level. Speeds on stretches decreased statistically significantly (p"0.05) at 60 out of 69 observed sections. The effects were largest on arterial roads, at mid-block sections, where the prevailing traffic conditions and street design allows higher speeds. The standard deviation decreased on all arterial roads, mainly due to the decrease in speed of the fastest vehicles but there is also an effect from an increase in speed of the slowest vehicles. On streets with mixed traffic no differences in speed or speed distribution could be shown. This is most likely due to the fact that speeds were already controlled by the prevailing traffic conditions and they already were so low that the system never had to interfere. Further research is needed in order to investigate possible behavioral adaptation effects when the system is active as well as inactive and how driver behavior would be influenced in a situation where a large part of the vehicle fleet equipped with an active accelerator pedal. (Less) Document type: Articl

Interaction between Cyclists and Motor Vehicles : the role of infrastructure design and vehicle characteristics

The aim of the project was to examine interactions between motor vehicle drivers and cyclists at intersections and the impact of infrastructure design and motor vehicle characteristics on interactive behaviour. The project activities included literature reviews on cycling infrastructure at intersections, vehicle driver behaviour and cyclist behaviour; questionnaires among motor vehicle drivers and cyclists across different cities in Sweden; field observations to investigate what cues cyclists use to interpret the intention of motor vehicles they interact with at signalised intersections; on-site interviews with cyclists to explore their strategy in an encounter with a motor vehicle; and a cycling simulator study to examine the behaviour of cyclists when approaching an intersection and the factors that may influence their decisions. The findings confirm that the way the cycling infrastructure is designed at intersections contributes to how cyclists and motor vehicles interact. Placing cyclists and motor vehicle drivers close (where they are visible to one another) at intersection areas increases the level of presence-awareness for both road users and consequently it increases safety. Though cyclists may feel more uncomfortable (exposed and unsafe) with this solution, they tend to be more careful and attentive. This finding from the literature was confirmed by the field observations showing that mixed traffic, i.e. “no cycle facility” at the intersection is the safest solution and the cycle lane solution is the least safe one. However, the on-site interviews with cyclists revealed that the large majority of the respondents preferred the infrastructure solution with a separated bicycle path. This is a typical case where objective safety and subjective safety stand in opposite relationship. The findings also revealed that one-directional cycle tracks enhance interaction at intersections, since motor vehicle drivers only expect cyclists from one direction. However, cyclists not following the rule and riding against the prescribed direction create problems and conflictive situations. Cyclists and the way they use the road infrastructure were found to be highly heterogeneous; the availability of cycling infrastructure at an intersection does not guarantee that cyclists use it as expected by designers and perhaps by motor vehicle drivers, as the infrastructure solution in some cases might not provide the shortest path for the cyclist. The uncertainty in cycling behaviour was found to be more at intersections with no cycling infrastructure. Confidence level among cyclists was found to affect their interaction with motor vehicles which tends to be hard for motor vehicle drivers to predict as different cyclists behave differently depending on their confidence in traffic.The majority of the interviewed cyclists said that when arriving at an intersection just after a motor vehicle they usually pass it on its right side. This was seen in observations on sites with cycle lane or cycle path but not on sites with mixed traffic. Also, if the motor vehicle was a heavy vehicle (bus or truck), somewhat fewer cyclists passed it on its right side. Also the cycling simulator study revealed that the most significant difference of longitudinal stop position was between the condition of a narrow lane without cycle lane marking and a truck standing at the stop line and the condition of wide lane with cycle lane marking and a car standing at the stop line, where the average stop position of the cyclist was behind the truck in the first condition and next to the car in the second condition. This finding corresponds to the test cyclists’ verbal expressions of the importance of “being visible and avoiding the blind spot”. The increased caution associated with the presence of a truck is motivated and in line with previous studies. At sites with mixed traffic (no cycle facility), compared to with cycle lane or cycle path, the cyclists’ scanning behaviour was more complete. At sites with cycle path, the cyclists looked for eye contact with the driver of the motor vehicle to a much larger extent than cyclists at the other two types of sites. Cyclists at sites with mixed traffic (no cycle facility) were more active in their visual search behaviour than cyclists at the other two types of sites. Also, those cyclists who passed the motor vehicle on its right side were more active in their visual search behaviour than those who did not pass the motor vehicle. The share of critical situations indicates that sites with mixed traffic (no cycle facility) is the safest solution and cycle lane solution is the least safe one

Inventory of best practices to prevent incursions into work zones - Literature review.

The aim of this report was to review the literature to identify existing best practices used to prevent incursions into work zones and improve safety of road users and road workers. A systematic literature search was conducted and various available sources referred to by knowledgeable experts in the field were considered. Best practices found in the literature review comprise both regulatory/management issues and technical issues

Measuring sustainability of transport in the city - development of an indicator-set

The HASTA indicator framework, covering the three dimensions of sustainability, i.e. Economic, Environmental and Social, to monitor sustainability of transport in Swedish cities was elaborated. Under the three sustainability dimensions, there are 6 sustainability aspects (indicator groups), 2-3 per dimension; these are Efficiency, Accessibility (Economic dimension), Accessibility, Safety, Liveability (Social dimension); Emissions, Resource use (Environmental dimension). The accessibility indicator group is related with both economic and social sustainability. The individual indicators are structured in three levels of a hierarchical structure. The highest level is represented by the Outcome indicators which reflect the sustainability target in the subject area of the indicator. These Outcome indicators are of both objectively measurable variables and subjective variables, reflecting how the inhabitants experience sustainability of transport in their city. On the lowest level, the Input indicators provide information on possible measures to make improvements in transport sustainability. On the intermediate level, the Output indicators show the effect of the adopted measures (Input indicators). There are 19 Outcome indicators, 22 Output indicators and 42 Input indicators

Road Safety Management at Work Zones : Final report

Accidents nearby work zones are a persistent road safety problem in many European countries. The Conference of European Directors of Roads (CEDR) has initiated and finances the IRIS project (Incursion Reduction to Increase Safety in road work zones) with the aim to collect and share information about best practices in temporary traffic management at road works. An analysis of work zone accidents and a review of best practices were made. Psychological issues to improve safety at work zones were studied by a literature review. Interviews with stakeholders were carried out in eight European countries to gather information on guidelines, standards and procedures in temporary traffic management. Best practice findings cover organizational/management issues, work zone safety reviews, establishment/de-establishment of a road work zone, informing/warning and guiding road users through work zone areas, speed management, protecting devices for road workers’ and road users’ safety and incursion warning systems

Strategies and tools for speed management on European roads.

The aim of the European project MASTER (MAnaging Speeds of Traffic on European Roads) is to produce information that can be cited in the preparation of national and EU decisions concerning speed management and standards for speed control equipment. For this purpose, the project seeks answers to three key questions:1) What are acceptable ranges of speeds?2) What are the key factors influencing drivers’ choice of speed?3) What are the best speed management tools and strategies?Each of three research areas addresses one of these questions. Area 1 is concerned with developing a basis for appraisal of effects of different levels of speed upon accident occurrence, emissions, noise, vehicle operating costs and travel time. Area 2 provides information on factors that influence drivers speed behaviour with respect to present speed levels and speed management methods in Europe, enforcement levels, motivation and acceptability of driving speeds, and road design and subjective road categorisation. Area 3 reviews various tools for speed management, tests the most promising ones and gives recommendations for implementation of Advanced Transport Telematics (ATT) systems. The summary reports from these three work areas provide the main inputs to this paper, which is concerned with making recommendations for speed management strategies and policies. The full results of the project are documented in 26 reports which are listed in the reference section of this paper

Review of current study methods for VRU safety : Appendix 4 –Systematic literature review: Naturalistic driving studies

With the aim of assessing the extent and nature of naturalistic studies involving vulnerable road users, a systematic literature review was carried out. The purpose of this review was to identify studies based on naturalistic data from VRUs (pedestrians, cyclists, moped riders and motorcyclists) to provide an overview of how data was collected and how data has been used. In the literature review, special attention is given to the use of naturalistic studies as a tool for road safety evaluations to gain knowledge on methodological issues for the design of a naturalistic study involving VRUs within the InDeV project. The review covered the following types of studies: •Studies collecting naturalistic data from vulnerable road users (pedestrians, cyclists, moped riders, motorcyclists). •Studies collecting accidents or safety-critical situations via smartphones from vulnerable road users and motorized vehicles. •Studies collecting falls that have not occurred on roads via smartphones. Four databases were used in the search for publications: ScienceDirect, Transport Research International Documentation (TRID), IEEE Xplore and PubMed. In addition to these four databases, six databases were screened to check if they contained references to publications not already included in the review. These databases were: Web of Science, Scopus, Google Scholar, Springerlink, Taylor & Francis and Engineering Village.The findings revealed that naturalistic studies of vulnerable road users have mainly been carried out by collecting data from cyclists and pedestrians and to a smaller degree of motorcyclists. To collect data, most studies used the built-in sensors of smartphones, although equipped bicycles or motorcycles were used in some studies. Other types of portable equipment was used to a lesser degree, particularly for cycling studies. The naturalistic studies were carried out with various purposes: mode classification, travel surveys, measuring the distance and number of trips travelled and conducting traffic counts. Naturalistic data was also used for assessment of the safety based on accidents, safety-critical events or other safety-related aspect such as speed behaviour, head turning and obstacle detection. Only few studies detect incidents automatically based on indicators collected via special equipment such as accelerometers, gyroscopes, GPS receivers, switches, etc. for assessing the safety by identifying accidents or safety-critical events. Instead, they rely on self-reporting or manual review of video footage. Despite this, the review indicates that there is a large potential of detecting accidents from naturalistic data. A large number of studies focused on the detection of falls among elderly people. Using smartphone sensors, the movements of the participants were monitored continuously. Most studies used acceleration as indicator of falls. In some cases, the acceleration was supplemented by rotation measurements to indicate that a fall had occurred. Most studies of using kinematic triggers for detection of falls, accidents and safety-critical events were primarily used for demonstration of prototypes of detection algorithms. Few studies have been tested on real accidents or falls. Instead, simulated falls were used both in studies of vulnerable road users and for studies of falls among elderly people

Säkrare fordon genom integrerade säkerhetssystem - en litteraturstudie

Föreliggande litteraturundersökning om integrerade säkerhetssystem i fordon visar att system som funnits ha en positiv trafiksäkerhetseffekt är: Adaptiv farthållare, Alkolås, Automatisk lagring av färddata (svarta lådan), Antisladdsystem, Bältespåminnare, Däcklufttryckskontroll, e-Call, Hastighetsanpassare (ISA), Kollisionsvarningssystem och Körfältsstöd. System som kan ge både positiva och negativa traffiksäkerhetseffekter är ABS, Trötthetsvarnare, Adaptiva strålkastare och Mörkerkörningsassistent. System för vilka inga kända utvärderingar med avseende på trafiksäkerhet påträffats: Automatisk fordonsidentifikation, Bromsstöd, Bältessträckare, Dödvinkelassistent, Elektroniskt körkort, Parkeringsstöd, Regnsensor, Start i motlutassistent, Väderinformation

Mätinstrument för uppföljning av transporthållbarhet i svenska kommuner

I det moderna samhället är en välplanerad infrastruktur med fungerande transporter och pendling en självklarhet. Transportsystemet har inverkan på fysisk och social miljö och det finns ett stort behov av att minska de negativa effekterna. Förutom tillgänglighet och minskad miljöpåverkan betonas ofta vikten av kostnadseffektivitet. Denna rapport beskriver ett verktyg framtaget inom ramen för HASTA programmet och som underlättar det systematiska arbetet med att nå kommunens hållbarhetsvision. Verktyget gör det möjligt att tydligt visualisera kommunens transporthållbarhetstillstånd. Med hjälp av HASTA:s verktyg – noggrant utvalda indikatorer i ett lättillängligt ramverk – kan kommunen kontinuerligt följa upp och förbättra sitt transporthållbarhetstillstånd