Science

Thousands of cyclists die in road accidents every year. Research by Schepers et al showed that the majority of these deaths, in the EU at least, were the result of collisions between vehicles and bicycles, mostly at unsignalised intersections. Prati et al have shown that in such cases the driver’s response plays a critical role in the outcome.

Vehicle manufacturers take either a passive or an active approach to protecting pedestrians and cyclists from collisions. The passive approach involves making the front of the vehicle softer with modified bumpers and external airbags. The active approach involves systems which can sense an impending collision and take evasive action such as automatic braking. There has been a large amount of research and development work in this area with such systems now being assessed within the Euro NCAP standard.

Study Design

This study is concerned with the active avoidance of collisions by car drivers. 44 drivers were instructed to drive through an intersection at speeds of either 30 km/h or 50 km/h. A bicycle then entered the intersection from their right side. The speed of the car was controlled and a light gate was used to trigger the bicycle to enter the intersection at repeatable positions relative to the car. The test track was digitized and 47 drivers completed the same exercises in a driving simulator. In total 947 trials were carried out.

The response of the drivers was recorded in terms of reaction time to take the foot off the gas pedal and to start braking. Some drivers showed proactive behavior releasing the gas pedal as the approached the intersection while others showed reactive behavior by not starting to release the gas pedal until they saw the cyclist. The arrival configuration of the bike and car was used to calculate a risk ratio for each trial. A regression analysis was then used to understand how the factors characterizing the driver’s behavior affected the risk to the cyclist.

Results

There were some differences in driver behavior in the simulator when compared to the track. The results showed that the most important factor was bicycle visibility. The sooner the bicycles became visible the more effectively the driver braked.

What it means for better bicycles

This study was mostly concerned with informing the design of road infrastructure and active safety systems in cars. That’s great, but what can this study tell us about creating better bicycles?

The biggest danger to cyclists is being hit by a vehicle at an intersection. Making yourself more visible, particularly from the side is the most important thing you can do.

When approaching a badly designed intersection, in which you are hidden by walls or bushes, a system which projects your presence ahead may be valuable. The Blaze Laserlight, therefore, looks like it has some real value, although this study has not directly tested it.

It’s also a good idea to slow down and be defensive of course. But in terms of bike design, side visibility is the takeaway message here.

Read the full paper

You can access the full paper here.

Modelling how drivers respond to a bicyclist crossing their path at an intersection: How do test track and driving simulator compare?

Christian-Nils Boda Marco Dozza Katarina Bohman Prateek Thalya Annika Larsson Nils Lubbe

Accident analysis and prevention. , 2018, Vol.111, p.238-250

The BicycleSafe website is dedicated to teaching cyclists how not to get hit by cars. It lists ten of the most common types of accidents and for each it one it gives tips on how to avoid it.

There is also lots of general advice. Key tips might seem obvious but it’s well worth going through them and thinking about your current habits. I should note that this advice isn’t referenced to any research. It’s just common sense advice.

Equipment:

• Use lights that are bright and clearly visible from all directions: front, rear and sides
• Wear bright clothing
• Get a rear view mirror

Behaviour:

• Avoid traffic if you can
• Slow down at intersections
• Get drivers attention
  • Signal before turning
  • Make eye contact and wave at drivers
• Position yourself where you can be seen on the road
  • Don’t ride too close to the curb
  • Stay in your lane: Don’t dip in and out of the cycle lane
  • Don’t stop in drivers blind spots
• Give yourself space around car doors
• Give yourself time to stop
• Don’t ride where you’re not allowed – you will also be unexpected
• Check your mirror before turning into or across traffic

A study carried out by Bath and Brunel Universities looked at how much space drivers give when overtaking. The researchers wanted to see if the clothing cyclists wear will affect drivers’ behavior. Different clothing was chosen to indicate different levels of experience. The extreme of inexperience was indicated by a cyclist wearing an outfit including a high visibility vest with the words, “Novice Cyclists, Pass Slowly”. At the other extreme the cyclist wore a racer outfit. A vest was also worn with the words, “Police Witness.com Move Over Camera Cyclist”.

Previous research is cited showing that drivers seem to have significantly reduced the room they give cyclists overtaking. The mean distance has decreased from about 1.8m in 1979 to about 1.2m in 2014. It is also interesting that drivers pass much closer in the morning than in the evening with the distance increasing linearly throughout the day.

A single male cyclist rode a consistent route for a number of months wearing each of the outfits. The route was the cyclist’s usual commute into West London, involving a wide range of different riding conditions over 26 km. Instruments were used to measure and log the proximity of each vehicle which passed. An ultrasonic sensor was used which has an accuracy of 1 cm and samples at 10 Hz. Data logging was carried out using an Arduino Uno. Plans for the replication of the test equipment are available from the authors Ian Walker, Ian Garrard and Felicity Jowitt.

Surprisingly there was no statistically significant difference in the mean passing distance for the novice or the racer. Drivers gave the same distance to an apparently experienced cyclist as they would to a novice.

There was, however, a small but significantly increased distance when the cyclist wore a vest indicating that the police were involved and they were being filmed.

Full details of the paper: The influence of a bicycle commuter’s appearance on drivers’ overtaking proximities: An on-road test of bicyclist stereotypes, high-visibility clothing and safety aids in the United Kingdom, Walker Garrard Jowitt, Accident analysis and prevention. , 2014, Vol.64, p.69-77

A study carried out in the Netherlands has compared the likelihood of crashes resulting in emergency treatment for eBike and regular bike riders. A survey carried out in emergency departments were used to gather data for the case group while a survey drawn from the population acted as the control group. The results were controlled for age, gender and bicycle use. The results suggest that although crashes for eBikes and regular bikes are of equal severity, eBike users are more likely to be involved in a collision.

The case group, those who had been involved in an accident, consisted of 294 eBike riders and 1699 regular bike riders. eBike riders experienced twice as many falls while mounting or dismounting and 30% more crashes while cornering but half the number of crashes while overtaking. However, the sample sizes are too small to establish statistical significance in these results.

It is noted that eBikes are generally significantly heavier than regular bikes. This increases the chance of falling when mounting or dismounting, common for older cyclists. Also, noted is the fact that eBikes are often front wheel drive which increases the likelihood of front wheel skidding and therefore loss of control. Another possible reason for the increased risk when riding eBikes is higher speed in relation to rider capability.

Abstract:

Use of electrically assisted bicycles with a maximum speed of 25 km/h is rapidly increasing. This growth has been particularly rapid in the Netherlands, yet very little research has been conducted to assess the road safety implications. This case-control study compares the likelihood of crashes for which treatment at an emergency department is needed and injury consequences for electric bicycles to classic bicycles in the Netherlands among users of 16 years and older. Data were gathered through a survey of victims treated at emergency departments. Additionally, a survey of cyclists without any known crash experience, drawn from a panel of the Dutch population acted as a control sample. Logistic regression analysis is used to compare the risk of crashes with electric and classical bicycles requiring treatment at an emergency department. Among the victims treated at an emergency department we compared those being hospitalized to those being send home after the treatment at the emergency department to compare the injury consequences between electric and classical bicycle victims. The results suggest that, after controlling for age, gender and amount of bicycle use, electric bicycle users are more likely to be involved in a crash that requires treatment at an emergency department due to a crash. Crashes with electric bicycles are about equally severe as crashes with classic bicycles. We advise further research to develop policies to minimize the risk and maximize the health benefits for users of electric bicycles.

Reference:

The safety of electrically assisted bicycles compared to classic bicycles
Schepers, J.P. (Ministry of Infrastructure and the Environment, Netherlands); Fishman, E.; Den Hertog, P.; Wolt, K. Klein; Schwab, A.L. Source: Accident Analysis and Prevention, v 73, p 174-180, December 2014

Read the full paper...

This study had the objective of measuring the ability of a bicycle safety education curriculum to “reduce the number of injuries and fatalities”. It involved testing middle school kids before and after they were given a bike safety course to determine how much their knowledge had increased. I have some issues with the methodology. It seems to me this study simply tested how well the kids retained the information taught in the course. This may result in reduced injuries and fatalities but this study really doesn’t demonstrate that. It would be nice to see a follow-up in which accident statistics for children who did the course are compared with a control group who have not had the training.

Abstract

Purpose The purpose of this study is to measure the effectiveness of a bicycle safety education curriculum for middle school age children in order to reduce the number of injuries and fatalities of bicyclists hit by cars in Miami-Dade County.

Methods The University of Miami BikeSafe® program includes a four day off-bike middle school curriculum that follows a train-the-trainer model, where a small number of staff trains a larger group of grades 6th-8th physical education teachers from various schools to teach the bike safety curriculum to their students. Subjects in this study included 193 students from 18 classes (3 per school) at 6 selected middle schools. Measures included a knowledge assessment of the curriculum that was administered to students pre- and post-curriculum implementation. Data were collected and analyzed with school and class period examined as predictors of post-score.

Results A significant difference (p .05), suggesting that a standard intervention was applied.

Conclusion The BikeSafe educational curriculum was found to improve the bike safety knowledge of middle school aged children. Future efforts will focus on sustaining and expanding this program throughout Miami-Dade County and other high risk communities.

Reference:

BikeSafe: Evaluating a bicycle safety program for middle school aged children
Hooshmand, Jonathan (University of Miami, Miller School of Medicine, United States); Hotz, Gillian; Neilson, Valerie; Chandler, Lauren Source: Accident Analysis and Prevention, v 66, p 182-186, May 2014

Read the full paper…

This study carried out telephone interviews with cyclists in Tasmania, Australia, to understand how frequently they had accidents. It found an overall accident rate of 1.6 major accidents and 3.7 minor accidents per 100,000 km ridden. Major accidents were defined as those requiring medical attention or resulting in a day or more off work. Minor accidents included only those which affected daily activities or had a financial cost. 37 percent of minor and 49 percent of major accidents involved a third party (cars, pedestrians, other cyclists etc). Surprisingly only 25 percent of major accidents involved a motor vehicle, the same as for those involving a pedestrian.

Although a wide range of factors were considered, due to the small sample size, in most cases no statistically significant correlations were found. Men were found to be less likely to have minor accidents while mountain biking significantly increased the likelihoodd of accidents, both minor and major. The study was carried out over eight months spanning 2011 to 2012. The 136 participants were recruited through approximately 700 e-mails and newsletters from cycling clubs and by adverts in bike shops.

Abstract:

Purpose: To characterise the demographics, cycling habits and accident rates of adult cyclists in Tasmania.

Methods: Volunteers ≥18 years of age who had cycled at least once/week over the previous month provided information on demographics; cycling experience; bicycles owned; hours/km/trips cycled per week; cycling purpose; protective equipment used; and major (required third-party medical treatment or resulted ≥1 day off work) or minor (interfered with individuals’ regular daily activities and/or caused financial costs) accidents while cycling.

Results: Over 8-months, 136 cyclists (70.6% male) completed the telephone survey. Mean (standard deviation) age was 45.4 (12.1) years with 17.1 (11.4) years of cycling experience. In the week prior to interview, cyclists averaged 6.6 trips/week (totalling 105.7 km or 5.0 h). The most common reason for cycling was commuting/transport (34% of trips), followed by training/health/fitness (28%). The incidence of major and minor cycling accidents was 1.6 (95% CI 1.1–2.0) and 3.7 (2.3–5.0) per 100,000 km, respectively. Male sex was associated with a significantly lower minor accident risk (incidence rate ratio = 0.34, p = 0.01).Mountain biking was associated with a significantly higher risk of minor accident compared with road or racing, touring, and city or commuting biking (p < 0.05).Conclusions: Physical activity of regular cyclists’ exceeds the level recommended for maintenance of health and wellbeing; cyclists also contributed substantially to the local economy. Accident rates are higher in this sample than previously reported in Tasmania and internationally. Mountain biking was associated with higher risks of both major and minor accidents compared to road/racing bike riding.

Reference:

Accident rates amongst regular bicycle riders in Tasmania, Australia
Palmer, Andrew J. (Menzies Research Institute Tasmania, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia); Si, Lei; Gordon, Jared M.; Saul, Tim; Curry, Beverley A.; Otahal, Petr; Hitchens, Peta L. Source: Accident Analysis and Prevention, v 72, p 376-381, November 2014

Read the full paper…