Category: Research

Bicycle flow modelling

Modelling bicycle flows at a reasonable scale is complex and not very well established yet. However, knowing when, where how many cyclists are on the road is crucially important for mobility management, transport planning and cycling promotion.
Before this background, a nationally funded research project called FamoS internet is dedicated to develop and evaluate two different modelling paradigms. Our partners at TU Graz internet expanded their intermodal four-step-model and integrated cycling. We at Z_GIS internet were responsible for testing an agent-based approach.

After 18 months of research and development – primarily driven by Dana internet, who is writing her PhD on ABM in transport modelling – we are able to present first results these days. At this year’s GEOSummit internet, the major GIS conference in Switzerland, I presented an introduction of how spatial information is employed in an agent-based modelling environment:

At the upcoming GI_Forum conference internet, Dana is going to give a presentation on her evaluation of ABM platforms for the purpose of bicycle flow modelling. The simulation model itself is going to be published in the Open ABM repository internet. A journal paper about the model is on the way.
You see, there is more to come! Stay tuned or get in contact internet with us right away.

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We need more data!

You have come across the claim that cycling is on the rise in cities all over Europe for sure. However, if you are looking for the statistics behind it you will be disappointed. Just try it and google for modal split development and cycling.

In their seminal paper Data driven geography internet, Miller and Goodchild state that “The context for geographic research has shifted from a data-scarce to a data-rich environment […]”. Thinking of the huge amount of data generated by an unprecedented number of sensors, this observation is absolutely true. Still, the story is a little bit different when it comes to the geography of cycling. Although the data volume is growing there as well – mainly due to the quantified-self-movement and the vast number of fitness and tracking apps – we are still in the situation that we cannot answer fundamental questions such as:

How many cyclists are on the road?

Where and when do they move through space?

How did the modal split develop over the past ten years?

The lack of adequate data and derived information is serious for a number of reasons:

  1. As long as the status-quo of cycling cannot be described by valid data, the demand for supportive policies, cycling friendly planning and funding does not become as obvious as it deserves to be. Cycling still suffers from a comparably low attention in the public discourse. And I dare to reason that the invisibility is partly due to the absence of hard facts.
  2. Although there is still room for improvement, authorities invest in cycling infrastructure and promotion. But in most cases they are unable to asses the effect of their interventions. Sometimes punctual counts and surveys are done, but the systemic effects remains hidden in most cases. Chris Rissel and colleagues provided a nice example in 2015 for how local interventions impact punctual investigations, but tend to have a rather low systemic effect (click here internet for the whole study).
  3. Without knowing when, where and which cyclists are on the road, it is hard to efficiently influence and manage cycling traffic. Even more important, as long as reasons for why persons do not cycle and local or temporal particularities remain unknown, it is impossible to target these persons and promote cycling among them. In other words, we desperately need qualitative survey data in addition to quantitative data, such as GPS trajectories, if we want to acquire an integrated picture of cycling mobility.

Interestingly, the situation has been anticipated on EU level for several years. In early 2017, Thérèse Steenberghen and colleagues published an extensive report internet on data availability for active modes. However, even on the country level, they diagnosed a lack of comparable data about walking and cycling, not to speak of the local level.

Yes indeed, we need more data. But before lots of data, which have minor relevance or do not contribute to answering the questions raised above, are acquired, fundamental issues need to be tackled:

Which kind of data do we need to get a holistic image of cycling mobility, to describe influential factors and to identify interdependencies between them?

Which data sources do already exist and how can additional data be efficiently acquired?

How can the availability and accessibility of data be increased in order to make them useable?

How can heterogeneous data be harmonized with regard to different data models, technical specifications and semantics?

What are efficient ways to establish monitoring systems in order to generate time series?

What are appropriate scale levels for data acquisition and analysis?

With regard to these issues, it becomes evident that we do not simply need more data, but more data that are relevant and additionally, more data intelligence. We have therefore recently launched a 30 months research project called Bicycle Observatory internet, in which we aim to develop an integrated perspective on cycling mobility and to further differentiate between the very different preferences and behavior patterns among cyclists.
In order to achieve these research goals we are currently evaluating existing data sources and will eventually complement them with additional data sources. A special focus lies on qualitative data from social research. The idea is to connect them to quantitative data on the basis of a common geographic reference.

Although the consortium covers a broad range of competencies and the partners bring in extensive networks, we are more than open for collaborations. Please drop me a line internet if you are interested in sharing your ideas, data, questions or examples!

Bicycle routing and safety

Back in 2016, I’ve presented a review study on bicycle routing portals and safety as routing criteria at the International Cycling Safety Congress in Bologna (ICSC internet).
Now, 16 months later, I’m happy to announce that an extended version of this contribution has been published in the Open Access journal Safety (follow this link internet to read the paper). Together with Hartwig Hochmair internet from the University of Florida, we updated and extended the study and derived recommendations on how to better address prevalent safety concerns in trip planners.

Safety concerns are still a major barrier for a larger bicycle mode share in everyday mobility (see e.g. Wegman et al. 2012 internet). In this article, we hypothesized that current online trip planners do not sufficiently consider safety as decisive criteria for route choice. Given the fact that  many cities around the world are still lacking of adequate, connected infrastructure, we consider trip planners as a potential element to bridge the gap between safety concerns and the built environment. Routing optimization could be used to highlight and recommend safe routes.
However, we have learned in our review study that virtually none of the investigated portals explicitly provides safety as a routing criteria. On the one hand this might be due to liability reasons, but on the other hand there are a few examples, which optimize routes in terms of safety (see this example internet, where the recommended route is explained as safest connection).

Factors that contribute to the routing criterion “safety” according to Hochmair 2005 internet (orange), and general routing criteria (green). Both classes are mapped to the analyzed portals in the matrix (right).

Geography and bicycling research

People’s mobility, and thus bicycling, is spatial by its very nature. Being mobile by bicycle means to ride from one location to another in a given environment. Fundamental geographical characteristics, such as neighborhood, accessibility or distance, determine mobility to a certain decree. However, these interdependencies are often neglected in bicycling research, planning and politics. The consequences of non-spatial approaches become evident in many cities: the environment (neighborhood) of bicycle ways is not considered and thus often unattractive or not suitable, central facilities are poorly linked to bicycle infrastructure (accessibility) or not straightly connected (distance). The graphs below show the increasing distance travelled by commuters in Austria. The proximity between place of residence and workplace directly affects the mode choice.

Klick on the image to open the interactive view.

In order to explicitly consider the spatial nature of bicycling mobility and to relate multiple perspectives on the environment, Geographical Information Systems (GIS) are increasingly employed in bicycling research and promotion. GI systems are capable to model and digitally represent all relevant physical objects (road infrastructure, facilities, land use etc.) and moving subjects, including quantitative and qualitative attributes. Using the geographical coordinate as common denominator, all entities, together with domain-specific attribution can be related to each other. This way, additional insights and new information about the multifaceted system of bicycling mobility can be gained.

Such integrated approaches are especially beneficial in the context of bicycling, where not only rational, but also subjective (for example with regard to safety) factors, together with interests of various stakeholders need to be considered. Facing and adequately addressing this complexity is also relevant in bicycle-related research. Explicitly geo-spatial approaches leverage existing domain knowledge and contribute to better results. Representing, modeling, analyzing and visualizing different perspectives on bicycling in a spatial framework leads to new knowledge and a strong evidence-base for informed discussions, participation processes and policies.

At this year’s POLIS conference internet I’ll present three case studies, which proof the integrative power of geography and the contribution of GIScience to bicycling research:

1. FamoS

Preliminary result of an agent-based bicycle flow simulation.

To strengthen active forms of mobility, it is necessary to adapt the road network in a way which allows optimal usage in spatial as well as temporal respect. The research project FamoS internet, started in September 2016, investigates the potential of traditional demand based traffic models (“4-step-model”) and of agent based simulation models to estimate the volume of bicycle traffic for entire cities at a maximum detailed scale level. These models are then fed into a novel planning tool, which facilitates evidence-based decisions in the process of planning and (re) organizing public space for active mobility.

2. GISMO

The research project GISMO internet, started in October 2016, integrates domain-specific know-how from various disciplines, namely GIScience, sports medicine and mobility management. As part of the project, the health effects of several interventions that promote sustainable, active mobility are investigated in a clinical study. These data are then combined with spatial models and analysis routines in a comprehensive map-based information platform, where the spatial characteristics of commuting trips and expected health effects are considered in mobility recommendations on an individual level. For a brief project update see my last post here internet.

3. Planning a Bike Sharing System

In order to transfer existing knowledge on Bike Sharing Systems (BSS) and parameters to a specific urban setting and to provide an evidence base for decision makers, we applied a generic spatial framework to the city of Salzburg (Austria), which merges spatial analysis results, expert knowledge and feedback from citizen participation processes. With this approach the potential demand could have been estimated for any location in town. Moreover, the contribution of each station location to the entire system was spatially modeled and optimized.
The spatial framework will be published and presented at next year’s TRA conference internet in Vienna.

In all thress presented cases solutions emerged that would have not be possible in the respective domain silos. However, the geographical space (concepts from geography and GIScience) is an efficient facilitator for cross-domain collaboration and knowledge generation. Domains (such as health science and medicine) and applications (such as transport modeling) which are often disconnected from bicycling research and promotion are integrated on the basis of common geographical coordinates. Consequently, the complexity of bicycling mobility can be better addressed when various perspectives on bicycling and respective interdependencies are explicitly considered.

P.S.: The presentation is available on Slideshare internet

 

GIS, commuting and health

Started in fall 2016, the ongoing research project GISMO internet (Geographical Information Support for Healthy Mobility) is the first of its kind – at least here in Austria. It brings together domain expertise from very different fields in order to generate an evidence base for companies that seek to improve their employee’s health. Medical doctors from sports medicine and cardiology, GI scientists, planners, traffic engineers and mobility consultants collaborate in a highly inter-disciplinary setting. The research project is funded by the Austrian ministry for transport, innovation and technology in the program MdZ internet.

Concept of the GISMO project.

The project’s main idea is the following: commuting to work is time-consuming and if done by private car bad for many reasons: congestions, noise, air pollution, space consuming, expensive and inactive. The project aims to tackle the last aspect and provides highly detailed information for companies about which return they can expect from investing into employee’s active mobility. It is important for employers to get an idea how effective different interventions are. On the other hand, employees can only be motivated to change well established commuting routines when the alternatives are realistic and attractive.
This is why we (a) started a clinical intervention study, (b) developed advanced routing algorithms and spatial models and (c) pack all the information into an intuitive, interactive information platform.

Lots of activities have been going on during the first twelve months:

A clinical intervention study with 70 subjects was designed. The study was approved by the responsible ethic board, before it was implemented in a large company.
The study design is the following: 70 car commuters are randomized either into two intervention groups or into a control group. In one intervention group subjects are motivated to switch to bicycle commuting. Subjects in the other intervention group switch to public transit and walking. All subjects are medically investigated before and after the intervention. Additionally, all subjects are required to document their commuting mobility in a diary. In order to validate this documentation and to derive estimations for the energy turnover, the subjects wear GPS fitness watches for two weeks in the beginning and another two weeks towards the end of the intervention.
The aim of this study is to estimate the health effect of active mobility interventions, which can be implemented in any company.

In order to recommend realistic routes for active commuting, we developed a sophisticated routing workflow, which makes use of a national, multi-modal routing service (VAO internet). The routes are optimized in terms of health (minimum distance for walking or bicycling) and travel time.
Together with the routing recommendations users of the platform are provided with spatial information about the quality of the environment. For this, we have developed spatial models that calculate walkability, bikeability and PT quality indices and map them at a very high spatial resolution.

Walkability and bikeability index for the federal state of Salzburg. The spatial resolution is 100x100m.

Currently, the project partner TraffiCon internet is developing the concept for the web-based information platform. A first proof-of-concept will be presented at next year’s TRA conference internet in Vienna. The platform will provide detailed information on health effects of active commuting, recommendations for individually optimized routes and information on potential interventions for companies.
Two master students at Z_GIS internet have started to analyse the GPS and heart rate data from the first data collection phase. First results look very promising with regard to mode detection and trip parameters.
The clinical study is going to run until May 2018 and first results are expected to be available soon afterwards.

As project leader I’m happy to say that the collaboration with partner from very different domains is extremely fruitful. Actually, we learn a lot from each other and it becam obvious that there are a lot more common interests (“What have GI scientists have to do with cardiologists?!”) than we had expected!
In order to share our experiences and to learn from others who are doing research in similar settings, we will organize a special session at the GI-Forum conference 2018 in Salzburg. The call for papers internet has already opened – you should definitely have a look at it.

 

Accessibility of kindergartens

Modal split for Austrian kindergartens and schools.

A recent publication of the national klimaaktiv internet program caught my attention last week. Following this report, 55% of all kids in Austria are brought to kindergarten by car. The share of kids cycling to kindergarten is below 5%.

One of my daughters on her way to kindergarten. We had a great winter season in 2016/17!

As the figures are for Austria, I don’t know if they are representative of my home town. Unfortunately, I haven’t found any statistics for Salzburg. My personal experience is that the number of kids on bicycles is very low – at least in my kids’ kindergarten. Most of the time we are the only one coming by bike.
Independently from the availability of statistics, open (government) data allowed me to do a bit of spatial analysis on the accessibility of kindergartens in Salzburg. The results are striking: there is virtually no need to bring kids to kindergarten by car in terms of distance or travel time. However, the environment of kindergartens is not always pedestrian- and bicyclist-friendly and of course, this impacts the mode choice for bringing and picking-up kids.

For the analysis I used the following data and settings:

  1. Address data are available from the federal Bundesamt für Eich- und Vermessungswesen. The dataset can be downloaded from their website internet.
  2. The location of kindergartens are published as OGD by the city administration. The most direct way to the data is to use this WFS internet. I need to add a disclaimer here: I’m not sure whether all kindergartens are included in this data set. Probably, not all private facilities are on the list.
  3. For the network analysis I used authoritative road data (GIP internet), published as OGD and enriched this dataset with additional information, which is also available via the national OGD portal internet.
  4. I used the routing engine from ArcGIS Desktop 10.4 for performing the network analysis.
    For the optimization of bicycle routes I employed the impedance model we have developed a few years ago for a bicycle routing service (see here internet and here internet for details). An average speed of 15 km/h (which might be a little bit too high) and global turn impedance at intersections were used as input parameters. For the pedestrian routes the shortest path was calculated and an average walking speed of 0.8 m/s was assumed.
  5. The walkability and bikeability index were modelled in the context of the GISMO internet research project; details are going to be published soon.

The average walking time to the next kindergarten, considering all address points in Salzburg is 8.14 minutes with a standard deviation of 6.10 minutes. The median is 6.86 minutes. 74% of all address points (16,741 of 22,694) are within 10 walking minutes from the next kindergarten. This means that 3 out of 4 kids could walk to kindergarten within a reasonable time.
These figures are even more striking when kids cycle to kindergarten. The average travel time is 2.90 minutes (!) with a standard deviation of 2.21 minutes. The median is 2.42 minutes. From 89% of all address points in Salzburg the next kindergarten could be reached in less than 5 minutes. This figures rises to incredible 98% for a maximum travel time of 10 minutes. Plotted on a map these figures look like this:

Travel time to the next kindergarten calculated for each address point in Salzburg. The left map shows travel times for pedestrians, the right one for bicyclists.

Although these numbers are striking, obviously, there are good reasons for parents not to let their kids walk or bicycle. Interestingly, the scientific evidence on influential factors on the mode choice for kindergarten-related trips is weak (not to say nonexistent). Studies of school pupils’ commuting trips reveal a significant impact of parent’s perception of the suitability of the environment on the mode choice (see for example Timperio et al. (2004) internet or Bringolf-Isler et al. (2008) internet). The impact of parents’ perception and behavior might be even bigger for kindergarten kids. In any case, the quality of the environment needs to be high in terms of pedestrian- and bicyclist-safety if active mobility should be further promoted. That this is currently not always the case, becomes obvious in the following maps:

Quality of the environment for pedestrians and bicyclists. Not all kindergarten locations are well-connected to a network of suitable (safe and comfortable) roads.

Last year, results of a large study on the relation of urban environments and level of physical activity were published in the prestigious medical journal The Lancet internet. The authors found that approximately 50% of the WHO recommendation of 150 minutes physical activity per week can be stimulated by an adequate environment.
Thus, the provision of safe and comfortable infrastructure has a huge effect, far beyond kids walking or cycling to kindergarten. Usually, this effect is quantified in terms of health, environment or economy. But apart from these important dimensions there is another one when it comes to kids. As Moran et al. (2017) internet proved earlier this year, the mode choice influences navigation skills and (spatial) knowledge of the neighborhood. As a geographer I’m tempted to conclude that these findings are a sufficient argument for further promoting active commuting to kindergarten and school!

Active mobility at GI-Forum conference

Today, I had the honour to chair another special session that dealt with GIS and mobility research at this year’s GI-Forum conference internet. The session “Spatial Perspectives on Active Mobility” was the third in a series (see here internet for a review of the 2016 and here internet for the 2015 session).
Of course, we will have a “Spatial Perspectives on …” session in 2018 again – the call will be published in December this year. So, consider this as an option for your publishing and dissemination strategy (by the way, the GI-Forum journal internet is open access!)

This year’s special session was a paper session with four speakers, who all went through a rigorous review process. The diversity of the contributions was high, demonstrating the wide range of mobility research where GIS plays a crucial role:

  • Irene Fellner internet from Vienna University of Economics and Business opened the session at the very local scale. She presented her work internet on landmark-based indoor navigation. Although the applied ILNM (“indoor landmark navigation model”), an extended version of Duckham’s et al. (2010 internet) LNM, performed well, Irene pointed to two major challenges: first of all, the ILNM requires very detailed data, which are not always available and secondly, the visibility of landmarks from the perspective of the user is not always given or unknown.
    Irene’s paper emerged from her master thesis at the University of Salzburg, where she successfully finished the UNIGIS MSc study program. Dr. Gudrun Wallentin, UNIGIS program director, regarded this special session as perfect stage to hand over the UNIGIS International Association (UIA internet) award for excellent master theses. Congratulations!
  • Ulrich Leth internet (Vienna University of Technology) presented the findings of a recent study where they investigated the impact of a bike sharing system on public transit ridership in the city of Vienna, which is famous for its extensive and well-performing public transit system. In total, Ulrich and colleagues analysed 1 million Citybike internet trips from 2015. Different to the expectation the title provoked, they found that the bike sharing system virtually has no impact on PT ridership, simply because of the huge difference in size and capacity. However, some details in their results were interesting and probably of relevance for other BSS: a) Citybike trips primarily substitute short and inconvenient PT trips, b) most bike sharing trips are made when the travel time ratio compared to public transit is 0,5 and c) the most popular OD relations are typical student trips (between transport hubs and university and student dormitories and transport hubs or universities).
  • Tabea Fian, a student from Georg Hauger’s internet (lead author of the paper) group, also from Vienna University of Technology, presented a spatial analysis of urban bicycle crashes in Vienna. Interestingly, the data were very similar to those I’ve extensively used in my PhD (see this paper internet). In a purely exploratory study design Georg has tried to identify blackspots in the network and tested for their significance. However, as it became evident in the discussion, final conclusions are hard to draw without a statistical population.
  • The last presentation was given by Anna Butzhammer internet from RSA iSpace. She presented parts of her excellent master thesis, in which she analysed the inter-modal accessibility of central places. For this, she developed a model that facilitates door-to-door travel time calculations with different modes. Her findings are especially important for planning and optimizing public transit systems, which can be regarded as backbone for sustainable mobility.

Tomorrow, the German-speaking sister conference, AGIT internet, will host a special forum on autonomous driving internet and on Friday I will chair another session on advances in GIS-T. Well, there will be a lot to discover, learn and discuss; if you don’t have the chance to be there physically, follow me on Twitter internet and stay updated.