1 3 Research and analysis Safety aspects of contraflow cycling cyclist's vademecum for the brussels capital region Detailed analysis of accidents involving cyclists on cyclist contraflows in the Brussels-Capital Region (2008, 2009 and 2010)
2 Research and analysis Cyclist contra-flows encourage more people to travel by bicycle, as they allow cyclists to use safe routes and avoid unnecessary detours. The aims of this study are to: evaluate the relative risk of cycling accidents in contra-flows compared to the rest of the road network, determine the proportion of accidents involving a cyclist travelling against the flow of traffic, understand the circumstances of recorded accidents in order to determine whether the road layout could have contributed to their occurrence, and propose recommendations for the design of contraflow schemes with a view to reducing the risk of accident. It implements Action 8.3 of the Road Safety Action Plan (Plan d actions sécurité routière/verkeersveiligheid Actieplan) of the Brussels-Capital Region, and pages 2.1 and 2.2 of the Cycling Plan (Plan Vélo/Fietsplan) of the Brussels-Capital Region. Authors Isabelle Chalanton (BRSI) Benoît Dupriez (BRSI) Contributors Marc Broeckaert (BRSI), Patricia Courange (BM) Marianne Courtois (BM), Florence Dekoster (BM), Frederik Depoortere (BM), Karl Determe (BM), Yves Englebin (BRSI), Jean-François Gaillet (BRSI), Françoise Godart (BM) Michèle Guillaume (BRSI), Isabelle Janssens (BM), Laurence Sailliez (BRSI), Ulric Schollaert (BM), Arnaud Verstraete (De Lille cabinet) Acknowledgements We thank the College of Attorneys General, which allowed us to consult the official accident reports; the managers and staff of the traffic accident department at the Brussels Police Prosecutor s Office, and the police precincts of Brussels-Ixelles, Brussels-Midi, Polbruno, and Uccle- Auderghem-Watermael-Boitsfort for their warm welcome during the analysis of the official reports; and Ms Caroline Zwaenepoel, of the Police Operational Information Directorate of the Federal Police, who sent us the essential identification numbers of the official reports. Layout Ria De Geyter (BRSI) This brochure can be downloaded from the sites: (webshop.ibsr.be) and Disponible en français. Beschikbaar in het Nederlands D/2014/0779/22 Publisher : Camille Thiry (Brussels Mobility) March 2014 Glossary BM BIVV IBSR BRSI Cyclist Vehicle Pedestrian Brussels Mobility Belgisch Instituut voor de Verkeersveiligheid (Belgian Road Safety Institute) Institut Belge pour la Sécurité Routière (Belgian Road Safety Institute) Belgian Road Safety Institute
3 Table of contents 3 Summary Introduction Objectives of the study Background Analysis of the literature Methodology The mapping step Mapping the contra-flows Mapping of accidents Selection of the accidents to be analysed Analysis of the accidents Initial observations Distribution and use of contra-flows One in four streets in the Brussels-Capital Region is a contra-flow Over 4 in 10 cyclists on contra-flows travel against the traffic General characteristics of accidents on contra-flows What proportion of accidents occurred on a contra-flow? What is the breakdown of accidents involving a cyclist on a contra-flow between accidents at intersections and accidents on road sections? Are contra-flows more dangerous than the rest of the road network? Are there more accidents when cyclists travel against the traffic? Are accidents involving cyclists travelling against the traffic on contra-flows serious? Is the breakdown of cycling accidents on contra-flows by age and gender significant? Is the breakdown of cycling accidents on a contra-flow by time significant?... 22
4 4 4 - Accident profiles Accidents at an intersection Accidents on a road section Points for discussion Does specific cycling infrastructure ensure safety? What are the possible types of conflict on a contra-flow? Are narrow contra-flows more hazardous? Does the positioning of parking on the right or the left have an impact on cyclist safety? Can profiles of the most dangerous road types be identified? Conclusions Annexes References... 44
5 1 Préalables Summary 5 One street in four in the Brussels- Capital Region has a cyclist contraflow There are 404 km (251 miles) of one-way streets with cyclist contra-flow in the Brussels- Capital Region, accounting for 25% of the road network open to cyclists. Nearly 91% of them are local access streets (the local network ), 6% are local collector roads, 2.5% are primary collector roads, and 0.5% are arterial roads (the primary network ). At 48% of intersections in the Region, one or more of the streets has a contra-flow. This is the case for 50.5% of intersections on the local network, 56% of intersections on local collector roads, 44% of intersections on primary collector roads, and 34% of intersections on the primary network. Thus contra-flows constitute a significant part of the Brussels cycling network and contribute to high cycle permeability throughout the city. Contra-flows are not road safety black spots Of the 992 cycle accidents analysed, 126 (or 12.7%) involved a cyclist travelling (in either direction) on a road with a cyclist contra-flow, entering an intersection from a contra-flow, or crossing an intersection while heading towards a contra-flow. Only 47 accidents out of 992, or 4.7% of all cycle accidents, involved a cyclist travelling against the traffic on a contra-flow. When the number of accidents by direction of travel is compared with the number of cyclists travelling in each direction, there are proportionally no more accidents involving a cyclist travelling against the traffic than with the traffic; in fact, there are slightly fewer. Studies conducted abroad confirm that the introduction of contra-flow cycling has not caused a rise in cycle accidents on the roads concerned, and given the advantages it presents, it has an overall positive effect on safety. Of the 47 accidents involving a cyclist travelling against the traffic, 31 (66%) occurred at an intersection. For cyclists travelling with the traffic, the proportion of accidents at intersections (40%) was below the overall average. On sections of road away from intersections the danger is therefore greater when the cyclist is travelling with the traffic, but at intersections the danger is greater when the cyclist is travelling against the traffic. Thus the risk of accident to cyclists travelling with the general traffic flow must not be underestimated, and where necessary solutions must be found. The highest accident risk for cyclists is on the primary network The type of road or intersection is a more decisive factor in the risk of a cycling accident than the introduction of contra-flow cycling. The risk of an accident occurring per km of road is over 15 times greater on a road section or intersection on the primary network than on a road section or intersection on the local network. On the local network, where most contra-flows are located, there are fewer cycle accidents per km on sections of road with contra-flow cycling than on sections of road without contra-flow cycling. On the basis of cyclist counts, the risk for a cyclist of being involved in an accident is approximately four times greater per km travelled on the primary network and twice as great on local collector and primary collector roads than on the local network.
6 summary 6 Failure to give way (yield) is the most common cause of accidents when the cyclist is travelling against the traffic The main causes of accident when a cyclist is travelling against the traffic are: failure to give way (yield) (by one or other of the two road users) at an intersection: 14 accidents poor positioning of the road users involved at an intersection: 7 accidents vehicle turning at an intersection, cutting across the path of an oncoming cyclist: 6 accidents vehicle leaving a parking space on a road section: 6 accidents pedestrian crossing a road section: 5 accidents oncoming vehicle on a road section: 4 accidents. Studies conducted abroad confirm that most accidents with a cyclist travelling against the traffic take place at an intersection. Accidents on a road section generally involve pedestrians who fail to check whether a cyclist is coming in the opposite direction.. Influence of the width of the roadway and the positioning of parking The narrowness of streets does not appear to be a major accident factor; narrow streets are awkward, but the number of accidents involving contra-flow cyclists is lower than the proportion of such streets in the road network. The risk to cyclists appears to be less where parking is situated on the left (the main traffic flow being on the right) than where parking is situated on the right. Parking on the left greatly reduces the risk of accidents involving drivers opening car doors without looking, but it involves two main risks for contra-flow cyclists: it encourages the cyclist to veer towards the centre of the road, which is a riskier position to be in when approaching intersections; and it can mask visibility for pedestrians crossing between two vehicles without paying attention to contra-flow cyclists. A follow-up study would be useful to confirm this analysis with a larger sample of observations. Conclusion Overall, the accident risk for cyclists travelling on, entering or leaving a contra-flow is low. Nonetheless, two conclusions can be drawn on intersections: (a) intersections should be properly designed in order to reduce speeds and increase mutual visibility; (b) road users should be encouraged to take greater care when approaching an intersection with a contra-flow.
7 7 1 - Introduction 1.1. Objectives of the study Brussels Mobility identified four objectives for this study: evaluate the relative risk of accidents for cyclists on contra-flows compared to the rest of the road network; determine the percentage of accidents involving a cyclist travelling against the traffic; understand the circumstances of the accidents to determine whether the road layout could have contributed to their occurrence; make recommendations regarding road layouts with a view to reducing the accident risk. Figure 2 - F19 + M4 road signs at the entrance to a contra-flow 1.2. Background Since 2004, highway authorities have been required to authorise two-way cycling on oneway streets. They can only refuse to do so on grounds of safety, such as insufficient road width, lack of visibility at bends, or excessive traffic speed that has not yet been reduced. Cyclist contra-flows, known in Belgium as limited one-way streets (sens unique limité/ SULs or beperkt eenrichtingsverkeer/bev), are indicated by (compulsory) road signs (Royal and Ministerial Decrees of 18 December 2002) and (optional) road markings. Available road width <2.6 m 2.6 m >3 m 3 m contra-flow prohibited contra-flow authorised contra-flow mandatory Figure 1 - Introduction of contra-flow cycling depending on available road width according to regulations (Sources: Royal and Ministerial Decrees of 18 December 2002; IBSR 2004) Figure 3 - C1 + M2 road signs at the exit from a contra-flow. Despite the advantages of contra-flows for cyclists - shortest route, avoidance of busy and/or dangerous main roads, eye contact when passing oncoming traffic - some contraflows are sometimes still perceived as being dangerous. It is therefore necessary to evaluate contra-flows in order to respond objectively to criticisms and comments. Chapter 2 explains the methodology used. The overall results of the study are presented in Chapter 3, while the accident scenarios identi-
8 introduction 8 fied as a result of detailed analysis of the official accident reports are discussed in Chapter 4. A number of specific issues are discussed in greater detail in Chapter Analysis of the literature There are few published studies on accidents involving cyclists travelling against the traffic on contra-flows. However, the progressive introduction of contra-flows in several cities provides us with initial feedback from neighbouring countries. In Germany, cyclist contra-flows have been allowed since 1997, and a few already existed before then. At the end of the 1980s, the city of Munster introduced a number of contra-flows. A study by Planungsgemeinschaft Verkehr (1992) showed that the number and severity of cycling accidents on the roads concerned remained almost unchanged. It also showed that the introduction of contra-flows improved traffic conditions for cyclists, which in turn led to increased use of contra-flows by cyclists. Over half of cyclists considered contra-flows to be safe, while most had encountered critical situations there. For their part, half of motorists believed that contra-flows were dangerous. The main problem cited by both cyclists and motorists was the road width, while most conflicts actually occur at intersections, as on narrow streets road users tend to slow down and adapt their behaviour. Narrow streets are nonetheless more problematic when there is more motorised traffic. The study concludes that the accident risk is similar, or even lower, when the cyclist travels against the traffic than when he travels with the traffic. Better signage of contra-flows, especially by means of road markings, and more awareness-raising measures are desirable. The study by Alrutz D. et al. (2002), conducted in 15 German cities, showed that most accidents involving a cyclist travelling against the traffic occurred with pedestrians who failed to check whether a cyclist was coming in the contra-flow direction. Accidents between a cyclist riding against the traffic and a motor vehicle are rather rare and occur mainly at an intersection. The study concludes that the introduction of contra-flows has no negative effects on road safety, and that it is even positive as it enables cyclists to get off busy main roads and use quiet back streets instead. These conclusions are confirmed by the study conducted by Ryley T and Davies D (1998) in London. Video sequences filmed on five contra-flows showed that cyclists travelling against the traffic were not in danger. Furthermore, no accident was recorded following the introduction of contra-flow cycling (during the study period). Most cyclists interviewed felt safe but believed that better signage was necessary. In France, 215 km (134 miles) of two-way cycling streets were opened during the summer of 2010 in 30 km/h (20 mph) zones in Paris. A study conducted at seven sites by Paris City Hall (2011) showed a sharp increase in use of the roads concerned by cyclists. Despite the increased number of cyclists, there was no increase in the number of accidents. The study also concluded that the introduction of contraflows is safe and that the much-feared head-on collisions are extremely rare, but that there is a conflict between contra-flow cyclists and pedestrians crossing between parked vehicles. Other studies conducted in France by CERTU [Centre for Studies on Road Networks, Transport, Urban Planning and Public Facilities] (Nuyttens, 2008) with the aim of evaluating contra-flows show that few accidents involve cyclists travelling against the traffic, and that all accidents occur at intersections.
9 9 introduction Finally, in Oslo, the Norwegian Centre for Transport Research has studied the introduction of contra-flows on two roads. In one case, video observations showed that the conversion of a parking lane into a contra-flow cycling lane led to a reduction in the number of conflicts between cyclists and pedestrians on the pavement (sidewalk), to the satisfaction of pedestrians. Thus in neighbouring countries the introduction of contra-flows has not caused a rise in cycling accidents on the roads in question and, given the advantages, has a positive overall effect on safety.
10 Methodology This study comprises two methodological components: the first involves mapping the contra-flows and identifying the exact location of cycling accidents in the Brussels-Capital Region; the second involves analysis of the accidents that occurred on contra-flows or at an intersection with a contra-flow The mapping step This step is necessary in order to determine which cycling accidents occurred on a contraflow or at an intersection with a contra-flow, as this information is not mentioned in the accident database provided by the Ministry of Economic Affairs (SPF Économie/FOD Economie), Directorate-General of Statistics and Economic Information (see explanations below) Mapping the contra-flows Mapping of the contra-flows is based on the UrbAdm_sa layer of Urbis We first identified the road network accessible to cyclists by eliminating motorways, tunnels and certain bridges. This network comprises 12,424 sections of roadway and has a total length of 1,654.2 km (1,027.9 miles). The mapping of one-way streets and one-way streets with cyclist contra-flow is based on the map of the Brussels-Capital Region for active travel modes (cycling and walking), September 2011 edition. As this source has some errors, it was checked against the One-Way Map application of the Brussels Regional Informatics Centre (CIRB/CIRG) and Google Street View. As these two sources are not entirely up to date, there may be some inaccuracies in the mapping of one-way streets and one-way streets with cyclist contra-flow Mapping of accidents The cycling accidents were first identified using the database of accidents involving injury compiled each year by the Ministry of Economic Affairs(SPF Économie/FOD Economie), Directorate-General of Statistics and Economic Information. These data, extracted from the forms for the analysis of traffic accidents with fatalities or injuries, are seriously underrecorded, especially with regard to slight injuries 2. In 2008, 2009 and 2010, 824 cycling accidents involving injury were recorded in the Brussels- Capital Region. These three years were chosen because contra-flows were rolled out across the 19 municipalities making up the region in Of these 824 accidents, 433 took place on a road section between intersections and 391 at an intersection. These accidents were mapped using the ArcGIS Online geolocation tool (in the absence, at this point in the study, of a geolocation tool based on the Urbis data). The location of most of the accidents at an intersection was verified manually. For 13% of the accidents on a road section no house number was given, which makes it impossible to identify the precise location. These accidents were assumed to have occurred in the middle of the road segment Selection of the accidents to be analysed The location of the accidents was identified using the ArcGIS projection system (WGS 84 projection). The map of the accidents was then imported into the Belgian Lambert 72 projection system, used for the URBIS data (which 1. The URBIS data are cartographic data generated by the Brussels Regional Informatics Centre (CIRB/CIBG). The UrbAdm_sa vector layer contains the centre line of all roadways in the Brussels-Capital Region. 2. Accidents with injury, and especially those involving vulnerable road users, are by no means all identified in the list compiled on the basis of the accident analysis forms:, the police are not called out to every accident with injury, especially where the cyclist is the only person involved, and the police do not always fill in an accident analysis form in addition to the accident report.
11 11 methodology had been used to map the contra-flows). Due to this change of reference system, these points may not be perfectly positioned on the correct street segment of the URBIS network. It was thus necessary to take account of this imprecision when selecting the accidents. For this, the selection of accidents located on a contra-flow segment was extended to include those located less than 10 metres from a contra-flow segment (using the select by location tool of ArcGIS). Nonetheless, some accidents whose location is out by more than 10 m may not have been selected, while they should have been. On the other hand, those that were selected in error (because they were less than 10 m from a contra-flow without having occurred there) were removed during the analysis. Mapping the accidents involving cyclists from 2008 to 2010 shows that 222 accidents (out of a total of 824) occurred on a contra-flow or at an intersection with a contra-flow. A previous study conducted in 2009 by the Belgian Road Safety Institute (IBSR/BIVV) (Dupriez, 2009) showed that 16 accidents (out of a total of 168) took place on a contra-flow or at an intersection with a contra-flow in 2005, 2006 and 2007 in the municipalities of Etterbeek, Evere, Saint- Josse-Ten-Noode/Sint-Joost-ten-Noode, Schaerbeek/Schaarbeek, Woluwe-Saint-Lambert/ Sint-Lambrechts-Woluwe and Woluwe-Saint- Pierre/Sint-Pieters-Woluwe. These accidents were added to the analysis, as in these six municipalities contra-flows were generalised in The study thus deals with 238 accidents that occurred on a contra-flow or at an intersection with a contra-flow. Four of the case files were not available for consultation; 234 accidents were therefore analysed Analysis of the accidents The accidents were reconstructed on the basis of the official accident reports. The files were consulted in the police precincts of Brussels-Ixelles/Brussel-Elsene, Brussels-Midi/ Brussel-Zuid, Polbruno, and Uccle-Auderghem- Watermael-Boitsfort/Ukkel-Oudergem-Watermaal-Bosvoorde and at the Brussels Police Prosecutor s office. The official report numbers, not included in the database provided by the Ministry of Economic Affairs, were provided by the Police Operational Information Directorate of the Federal Police. Each file was then studied using an analysis chart that includes data on the locations, the road users, the sequence of events in the accident (divided into four phases 3 ) and several factors judged to contribute to an accident (see the analysis charts in the Annex). Field visits were then made to determine the extent to which the road layout could have played a role in the accident. In the vast majority of cases, the road layout had not changed between the time of the accident and that of the analysis. Where it had changed, it was still possible to reconstruct the road layout at the time of the accident relatively accurately, in particular using aerial photographs. Following the analysis, cases considered similar were grouped together on the basis of the sequence of events in the accident to obtain several accident profiles. 3. Namely, the driving situation, the accident situation, the emergency situation and the collision situation. This sequential analysis of the accidents follows that proposed by INRETS (French National Institute for Transport and Safety Research) (Brenac et al., 2003).
12 fiche n o Initial observations 3.1. Distribution and use of contra-flows One in four streets in the Brussels-Capital Region is a contra-flow Network accessible to cyclists Two-way One-way with contra-flow One-way Kilometers Figure 4 - One-way streets in the Brussels-Capital Region (2009).
13 13 initial observations Mapping the one-way streets shows that there are 3,116 sections of one-way street with cyclist contra-flow out of a total of 12,424 road sections accessible to cyclists in the Brussels- Capital Region, or 25% of the roads. The total length of contra-flows is linear km, or 24% of the 1,654 km of roadways accessible to cyclists. There are 722 sections of one-way street without contra-flow cycling, making a total of 88.9 km. The breakdown of contra-flows by hierarchical level of road, as defined in the Iris 2 regional mobility plan (see Figure 7), is as follows: Hierarchy Total number of road sections Number of contra-flow sections Percentage of contra-flow sections in this category (%) Total number of intersections 4 Number of intersections with at least one contra-flow Percentage of intersections with at least one contra-flow in this category (%) Local network , ,5 Local collector road Primary collector road Primary network , , , , , Total , Figure 5 - Road hierarchy as defined in the Iris 2 plan Almost 91% of contra-flows are on the local network, 6% on local collector roads, 2.5% on primary collector roads, and 0.5% on the primary network. At 48% of all intersections in the region, at least one of the roads is a contra-flow; 50.5% of intersections on the local network include at least one contra-flow, compared with 56% on local collector roads, 44% on primary collector roads, and 34% on the primary network. Thus contra-flows constitute a major part of the Brussels cycling network and contribute to a high permeability of cyclists throughout the city Over 4 in 10 cyclists on contra-flows travel against the traffic The recent series of cyclist counts organised by Provelo, Cyclists count 6, provided some information on the use of contra-flows by cyclists. Of the 212 cyclist counts conducted on the local road network (106 different sites), 87 of them on contra-flows (43 different sites), the average number of cyclists counted was greater on contra-flows than on two-way or one-way streets: approximately 10 cyclists per site (observed over 20 minutes) compared with approximately 8 on the other roads. 4. Intersections were categorised according to the highest hierarchical level of road present. We took into account only those accessible to cyclists. 5. The hierarchical level of the road is not specified for all segments on the map file provided by Brussels Mobility. 6. These data come from 381 individual 20-minute counts, carried out during the rush hour by cyclist counters at locations chosen by them during a specified one-week period. While these data have no scientific value, the large number of individual counts provides orders of magnitude which are useful for the purposes of this analysis. Campaign site:
14 initial observations 14 These counts also show that 56% of cyclists travelling on contra-flow sections of the local road network are travelling with the traffic and 44% against it General characteristics of accidents on contra-flows Although this data should be treated with caution, it is the only information available in such detail, and provides at least orders of magnitude on use of the road network by cyclists What proportion of accidents occurred on a contra-flow? 992 accidents* 758 No contra-flow in the vicinity no presence of a contra-flow? yes 60 No user on the contra-flow 48 Other vehicle on the contra-flow no no presence of one of the 2 users on the contra-flow? yes Cyclist on the contra-flow? yes 79 Cyclist riding with the traffic on the contra-flow no Cyclist riding against the traffic on the contra- yes 47 Cyclist riding against the traffic on the contra-flow Figure 6 - Breakdown of cycling accidents in the Brussels-Capital Region by type of road (with or without a contra-flow) and by direction of travel of the cyclist * 824 accidents out of the 19 municipalities (years 2008 to 2010) accidents out of 6 municipalities (years 2005 to 2007) = 992 accidents.
15 15 initial observations Of the 992 cycling accidents analysed, 126, or 12.7%, involved a cyclist travelling on a contraflow, entering an intersection from a contra-flow, or crossing an intersection towards a contra-flow. Accidents involving a cyclist travelling against the traffic on a contra-flow accounted for 47 cases out of 992, or 4.7% of all accidents involving cyclists. In 48 accidents the other vehicle was on the contra-flow section, and in 60 cases none of the users involved was coming from or heading towards the contra-flow section. A concentration of cycling accidents was observed on the primary network and on the central boulevards. related to the contra-flow (n=115) not related to the contra-flow (n=107) not on a contra-flow motorway/trunk/arterial road primary collector road local collector road local access road kilometers Figure 7 - Cycling accidents in the Brussels-Capital Region in 2008, 2009 and 2010 and hierarchy of roadways.
16 initial observations What is the breakdown of accidents involving a cyclist on a contra-flow between accidents at intersections and accidents on road sections? As can be seen in Figure 8, of the 992 accidents involving a cyclist, 47.8% occurred at an intersection. Of the 126 accidents involving a cyclist travelling on a contra-flow, entering an intersection from a contra-flow or entering a contra-flow, a similar proportion (48.7%) occurred at an intersection. Section n=514 Intersection n=478 on a section not on a contra-flow at an intersection without a contra-flow or other vehicle on contraflow (n=48) on a section on a contra-flow - cyclist with the traffic at an intersection with a contra-flow- cyclist with the traffic on a section on a contra-flow - cyclist against the traffic at an intersection with a contra-flow - cyclist against the traffic Figure 8 - Breakdown of cycling accidents in the Brussels-Capital Region between those at or not at an intersection, those with or without a contra-flow in the vicinity, and the direction of travel of the cyclist. Figure 9 shows that of the 47 accidents involving a cyclist travelling against the traffic, 31 (66%) occurred at an intersection. In the case of cyclists travelling with the traffic, accidents at intersections were, at 39.7%, below the overall average. The danger is therefore greater when the cyclist is travelling with the traffic on a road section or against the traffic at an intersection. Thus the risk of accident for a cyclist travelling with the traffic must not be underestimated, and where necessary measures must be taken to reduce it. Intersections at the exit from a contra-flow should also be laid out in such a way as to reduce traffic speeds and increase mutual visibility. Road users should also be encouraged to take extra care when approaching an intersection with a contra-flow.
17 17 initial observations 100% 90% 80% 70% 512 ON A ROAD SECTION % 50% 40% average 30% 20% 10% AT AN INTERSECTION 31 0% total cyclist on a contraflow travelling with the traffic cyclist on a contra-flow against the traffic Figure 9 - Comparison of the number of cycling accidents at an intersection and on a road section Are contra-flows more dangerous than the rest of the road network? On a road section Nearly 91% of contra-flows are on the local network. They should therefore be compared primarily with this type of road. Contra-flows account for 32.9% of the total length of the local network, and had 30.5% of the accidents that occurred on the local network. The rest of the contra-flows are distributed as follows: 6% on local collector roads, 2.5% on primary collector roads, and 0.5% on the primary network. When the number of accidents involving cyclists on a road section is divided by the number of kilometres of each category of road, the following results are obtained (see Figure 10): On a road section, the level of danger for a cyclist travelling on the local network is thus 5 to 6 times less per km travelled than on the primary network, and 3 to 4 times less than on a primary collector road. On the local network, contra-flow road sections even appear to give rise to fewer accidents per km of road than other roads (two-way or ordinary one-way). On the rest of the road network, the number of cycling accidents on a section is too small to be able to make the same distinction between roads with and without contra-flows.
18 initial observations 18 25,0 24,8 20,0 15,0 15,6 13,8 10,0 5,0 average 4,4 3,9 0,0 Primary Primary collector Local collector Local roadway not contra-flow Local roadway contra-flow Figure 10 - Number of cycling accidents on a road section per 100 km of road (Brussels-Capital Region, 2008 to 2010, N=824). At an intersection The breakdown of accidents by hierarchical level of intersection is as follows: Primary Primary collector Local collector Local % of intersections 12 19, ,3 Of which, % of intersections with at least one contra-flow ,5 % of cycling accidents 37,5 30,6 17,2 14,7 Of which, cycling accidents related to the contra-flow(%) 1,3 6,1 1,8 5,1 Figure 11 - Number of cycling accidents at an intersection by hierarchical level. The proportion of cycling accidents occurring at an intersection on the primary network (37.5% of all accidents) is three times the proportion of intersections located on the primary network (12% of all intersections). This table also shows that the proportion of accidents related to the contra-flow is greater at intersections on primary collectors. Intersections on primary collectors and the primary network with a contra-flow must therefore be carefully designed.
19 19 initial observations Road sections and intersections Figure 12 shows that on the primary network, primary collectors and local collectors there are more cycling accidents at intersections than on road sections. Conversely, on the local road network, more accidents take place on a road section. It should be noted, however, that the Ministry of the Brussels-Capital Region classifies intersections according to the highest hierarchical level of road present. As a result the higher hierarchical levels are somewhat over-represented. The risk per km of road can be found by dividing the number of accidents that occurred on each of the categories of the network (road section + intersection) by the linear distance of this category. Figure 13 shows that the risk of accident per km of roadway is over 15 times greater on a road section or intersection on the primary network than on a road section or intersection on the local network. This means that improving safety by redesigning 1 km of the primary network will have a significantly greater effect on the road safety of cyclists than redesigning 1 km of the local network. The accident rate on local collector roads is very similar to that on primary collector roads, even though local collector roads are supposed to resemble local roads more closely than primary collector roads (see the Regional Development Plan). 160 not related to a contra-flow related to a contra-flow - cyclist travelling with the traffic related to a contra-flow - cyclist travelling against the traffic Accidents not related to a contra-flow Accidents related to a contra-flow and with cyclist going with the traffic Accidents related to a contra-flow and with cyclist going against the traffic # accidents Road Section Primary Intersection Road Section Intersection Primary collector Road Section Road Section Local 156 km 231 km 155 km 1108 km Figure 12 - Number of cycling accidents at an intersection or on a road section by hierarchical level (Brussels-Capital Region, , N=824). Intersection Local collector Intersection Number of accidents per 100 km of road and per year Primary Primary collector Local collector Local average 156 km 231 km 155 km 1108 km Figure 13 - Relative risk of a cycling accident (road section or intersection) per 100 km of road by hierarchical level (Brussels-Capital Region, , N=824).
20 initial observations 20 The average risk for a cyclist (the concept of "risk exposure") can be calculated by dividing the number of accidents per km of road by the average number of cyclists who use that type of road. The only data available on the number of cyclists by hierarchical level of road come from the "Cyclists count" data collected by Provelo in These figures should be treated with caution, but they nonetheless reveal a general trend. The results obtained by Provelo are as follows : Hierarchical level of the road Primary network Primary collector Local collector Local network # cyclists on average/20 min Figure 14 : Number of cyclists by hierarchical level of roadways (Source: Provelo). On the basis of the above cyclist counts, Figure 15 shows that the accident risk per km travelled on the local road network is below the average for the entire road network (=1), while the accident risk on other road types is above average. Relative risk of accident per km travelled by bike 2,5 2,0 1,5 1,0 0,5 0,0 Accidents not related to a contra-flow Accidents related to a contra-flow Primary Primary collector Local collector average Local 156 km 231 km 155 km 1108 km The accident risk for a cyclist per km travelled is approximately 4 times greater on the primary network and twice as high on primary collector or local collector roads as on the local network. The counts appear to show that there are more cyclists on contra-flow sections than on other sections of the local network. If these counts are confirmed, they would tend to show that the risk for a cyclist per km travelled is less on a contra-flow section of the local network than on other sections of the local network. Overall It is clear that the hierarchical level of the road section or intersection is a more decisive risk factor for bike accidents than the introduction of contra-flow cycling on one-way streets. On the local network, where most contra-flows are found, the number of cycling accidents per km is lower on contra-flows than on other roads. Figure 15 - Relative risk of accident per km travelled by bike (Brussels-Capital Region, , N=824, Provelo cyclist counts). 7.