GI-Forum 2014: Assessing bicycle safety in road networks

Assessing bicycle safety in multiple networks with different data models

Martin LoidlDepartment of Geoinformatics, Z_GIS

University of Salzburg

[email protected]

GI-Forum 2014, Salzburg

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Context

Why bicycle safety?!

www.zeitpunkt.ch

“Road safety: Second good year in a row puts Europe firmly on track towards target” (EC - IP/14/341; 31/03/2014)Another worrying feature of the statistics is the situation of vulnerable road users: The number of pedestrians killed is decreasing to a lesser extent than expected and the number of cyclists killed has recently even been increasing. This is partly due to the fact that more and more people cycle; the challenge for Member States is to encourage people to use their bicycles rather than their cars more often, but to make sure that the shift from car to bicycle is a safe one.

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How can we contribute to safety improvements for bicyclists?

Numbe

r of b

icycli

stsNum

ber of accidents

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Assessment

Status-quo analysis Weak-point analysis Corridors etc.

Planning & Infrastructure Priority of measures Budget allocation etc.

Information Routing etc.

www.stadt-salzburg.at

www.stadt-salzburg.at

www.radlkarte.eu

Assessm

en

t of N

etw

ork

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How to assess road networks

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Assessment Method I

Fuzzy results From grades to verbal description

Assessment standard hardly to establish Person, time, location

Requires much effort E.g. re-assessment after every physical

modification of road space

Expert knowledge as input for assessment procedure Sub-optimal for global assessment approach

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Assessment Method II

Conceptual fallacy Absolute (!) number of accidents no indication

for unsafe roads Function of N External effects

Accident analysis for detection of risk factors or hot spot analysis

http://gicycle.wordpress.com

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Assessment Method III

Not equally distributed over space Coverage in remote vs. central areas

Data Representative only for specific sub-groups

Semantic challenge Ontologies for feedback assessment

For punctual validation/calibration For group-specific analysis, qualitative assessment Not yet applicable for global assessment = research topic!

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Indicator-basedAssessment Model

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Loidl & Zagel (2010)

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Problem Statement

Bicycle routing service with „safety“ as routing criteria Different data sets from different sources Different data models

Geometry and attributes

Different environments to adapt the model for Urban vs. rural

type = roadbicycle_infra = cycleway

type = road

type = cycleway

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Study Area & Data

Authoritative data for city of Salzburg 11,458 edges 1,119.7 km net length

OpenstreetMap extract for adjacent municipalities (1A, 4G) 9,601 edges 941.3 km net length

Data sets with different data model and attribute structure

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Data models

Authoritative graph Center line Complex attributive formulation of bicycle infrastructure Complete and homogeneous

DB-Name Attribute Value Value descriptionSIC_STRAS4 Road category 400 Municipal roadSIC_STRAS5 Max.speed, km/h 50 SIC_STRA9 Buslane 1 Yes, FTSIC_STR13 Oneway 1 Yes, FTSIC_RAD_RE Bicycle infrastructure (right side, FT) 10 Yes, undefinedSIC_RAD_R1 Bicycle infrastructure (left side) 5 Cycle-/footway mixedSIC_RAD_RI Direction bicycle infrastructure (FT) 0 NoSIC_RAD_R5 Direction bicycle infrastructure (TF) 4 Both directions, independet from onewaySIC_STR24 Motorized traffic load, V/24h (TF) 0 SIC_STR25 Motorized traffic load, V/24h (FT) 17698

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Data models

OSM graph Edge for every physically separated

lane Very simple tag (key = value)

structure Up-to-date Gaps, inconsistencies, errors,

heterogeneous attribute structureKey Valuehighway pathbicycle designatedfoot designatedsurface paved

Loidl et al. (2014), Aufbereitung von Open Street Map Daten für GIS-Modellierungen und Analysen. AGIT

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Workflow

Define transition points between networks

Line matching and integration of transition

edges

Identify indicators for urban and rural

environment

Find corresponding attributes in digital data

Run indicator-based assessment model for

both environments

Z-transformation for index values

Rivers » bridgesHighway » ring underpasses

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Geometry & Topology Transfer points

Bridges, under-/overpasses Transition edges Line matching

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Assessment Model

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Result

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Application

www.radlkarte.eu

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Conclusion

Indicator-based assessment model Transparent Comparable Adaptable and scaleable Reproducable

Applicable in several contexts Proof of concept: safe bicycle routing Planning and simulation tool

GIS „intelligence“ helps for modelling in heterogeneous environment (data, geography, …)

@gicycle_

gicycle.wordpress.com