BICYCLING SAFETY: Preventing Injury Requires Multiple Strategies

In recent years, bicycling has increased nationwide.  However, the growing numbers are most visible in urban areas where car congestion and mixed-use density make cycling particularly useful, which also gives bicyclists the political clout to push for improved safety facilities.


Bicycling isn’t just faster and cheaper than other forms of urban travel, it’s also healthier.  Regular bicyclists live, on average two years longer than non-cyclists and have a level of fitness equivalent to someone 10 years younger.  Students who bike (or walk) to school perform better on tests, regardless of the amount of other out-of-school physical activity.  Overweight adolescents who bicycle at least half the week are 85% more likely to become normal-weight adults.  The health benefits of cycling have a positive impact 20 times larger than the negative impact of safety risks experienced by cyclists.

Which isn’t to say that anyone wants to be in a bike accident, or that cycling is safe enough.  But there are no “silver bullet” single solutions.  Success requires understanding the full range of strategies and implementing as much as possible of each.

Around 75% of bicycling accidents are “solo” events, due to potholes or the rider’s own errors.  But these tend to cause minor injuries rather than death.  Being hit by a car, truck, or bus is more serious.  Aggressive passing, turning into a cyclist’s path, speeding, running red lights or stop signs – these are the driver actions that are at least a contributing cause in up to 85% of cyclist fatalities.  According to the Boston Bicycle program, the city had 8,329 car crashes in 2012 of which 426 involved a bicyclist, leading to 5 cyclist deaths.  The small increase in bike injuries from 2010 to 2012 occurred almost entirely during the darker winter months when the rent-a-bike Hubway stations were closed.  And while only 2% of Emergency Room visits resulting from bike accidents are for head injuries, these lead to 36% of the subsequent move from ER triage to a hospital admission.

Just as Medicine focuses on making sick people better, there are ways at both the individual and policy levels to reduce the severity of accidents.  Public Health, in contrast, seeks to prevent people from becoming ill in the first place – and there are also a very broad range of actions at both the individual and policy levels to reduce the likelihood that an accident will happen.

Post-accident, injury reducing actions are mostly and best done voluntarily by individuals (for example: wearing a MIPS helmet or signing up for a bike skills training class) although there are a few things that can be done on a policy basis to protect people from accident-caused injury (such as requiring trucks and buses to have “side guards”).   Fortunately, however, there are many things that can be done to reduce the odds of having an accident in the first place.  These range from increased training, to road design (providing more traffic-separated protected bike lanes of various kinds), to bans on distracting driving (and cycling!), and more.  Increased safety for bicyclists, and for everyone else, requires understanding each of the approaches suggested by each strategy, and then making sure that as many as possible get implemented.

Policy changes can be focused on the transportation context or on society at large.  As with the public health hierarchy illustrated in CDC Director Dr. Thomas Friedman’s Health Impact Pyramid the sweet spot is somewhere in the middle – actions that provide the greatest amount of improvement for the largest number of people at the least per-person cost and are most likely to be both technically and politically do-able.  


There are three strategic approaches to think about reducing serious injury or death among cyclists.  The first two – Keeping Bicycles Off The Roads and Treating Bicycles Like Cars – both provide important insights, but have major limitations.  The third strategy – Safety Through Numbers – not only improves safety but has enormous additional public health benefits and will be the main focus of this blog.  Making bicycling mainstream – getting many more people to use a bicycle more often for more types of trips – requires making it both objectively and perceptually safer.


In Europe bicycling remained a common, although declining, form of transportation well into the second half of the Twentieth Century, partly because of the poverty and infrastructure destruction caused by two World Wars and partly because of the region’s relatively compact built environment.  In the United States over those same years bicycling was nearly totally replaced by cars and local roads were overlaid with an extensive Interstate Highway System – from which bicycles and pedestrians were forbidden, particularly in the eastern states.   When Europe eventually built highways, they often placed bike/pedestrian (multi-use) paths alongside.  In the US, there were no such accommodations.

In post-WWII America, the roads were for motorized vehicles and bikes were for kids.  The decline of adult cycling was so extreme that the country that had once hosted more bike races of more types than any other was suddenly nearly empty of facilities and fans.  No bikes on the road – no accidents involving cyclists.

Not that the roads were safe, even for cars, but millions of dollars were poured into research and it was discovered that wide travel lanes, soft curves, broad shoulders, the absence of distractions, easy-to-read large signs, were among the ways to make highways more “error tolerant” for drivers moving at high speeds.  These prized insights were codified in road design manuals and engineering curricula, and slowly applied not only to the Interstate but to local arterials and other local roads.

The strategy was simply to keep bikes and cars apart.  The unfortunate result is that this often results in a society with no adult bicyclists.  But it does embody the true insight that the combination can be dangerous and that the primary reason most non-cyclists give for staying off the road is fear of traffic.


Faced with the threat of exclusion, and in opposition to what he considered dangerously misguided bike safety regulations, industrial engineer and avid cyclist John Forrester came up with the concept that bikes were simply vehicles and therefore had as much right as any other vehicle to be on the public right of way.  Vehicular cycling developed a whole curriculum of important skills appropriate to bicycling in traffic, called “Effective Cycling,” that still forms the basis of most American bicycling training programs.

However, if bikes are human-powered cars then cyclists have to act like car engines.  In the Vehicular Cycling world, it’s the job of the cyclist to keep up with traffic.  Which means that if you are not fit and bold you shouldn’t be using your bike.  In practice, this means that the young, the old, most women, and the inexperienced are excluded.  Furthermore, since most non-whites, particularly African-Americans, feel that the police are predisposed to question the legitimacy of their presence – as the frequency of “Driving While Black” and “Stop and Frisk” pull-overs confirms – they are unlikely to risk being so visibly non-conforming.

Today, Vehicular Cycling is a very small – although often vocal – current of thought within the bicycling community.   Originally, this camp opposed all “bike only” facilities – from bike lanes to traffic-separated cycle tracks – on the grounds that they would lead to the exclusion of their “advanced cyclists” from the rest of the road:  a fear that adherents of the old “bikes don’t belong at all” school do their best to validate.   However, as the presence of bike lanes and other facilities has drawn increasing numbers of cyclists, the Vehicular crowd has learned to avoid outright condemnation and focus on the ways that every proposed bike accommodation is imperfect and therefore will inevitably lead to accidents.   Anti-bike traditionalists within the traffic engineering profession often seize on this “lack of agreement within the bicycling community” as a justification to not include bike facilities in their designs.  But the growing acceptance of “Complete Streets” as a guiding philosophy will eventually render this delaying tactic ineffective as well.


Safety comes from numbers” is the mantra of most bicycle advocates today.  When comparing nations, cities, and even neighborhoods, it is clear that places with the highest number of bicyclists and rate of bicycling have the lowest rate of serious injuries or fatalities.  The effect is so strong that sometimes increasing numbers are even accompanied by a drop in the absolute number of serious bicyclist injuries and fatalities.

Bicycle advocates want to raise the “mode share” of bicycling from its current US level of under 2% of trips to anywhere between MassDOT’s 2030 goal of 4.3% to Boston’s 2020 target of 10%, or even to the current Amsterdam/Copenhagen levels of 25% to 36%.  Although most advocates assume this will be accompanied by a huge increase in the availability of bike riding skill training opportunities, few people believe that all the “newbies” will have superior bike-handling skills:  solo accidents and their typically minor injuries are likely to increase. Neither will the new cyclists have more traffic-tolerant attitudes:  they are unlikely to get on their bikes unless there is a vast increase in the availability of  bike lanes, “protected bike lanes”, “cycle-tracks”, off-road paths, and other low-traffic-stress facilities.

Regardless of the general level of cyclist skill, increased numbers of bicyclists will have several major safety impacts that will reduce serious injury and death resulting from car-bike collisions First, car drivers will become much more used to the presence of cyclists and will adjust their behavior accordingly.  Second, more car drivers will also be cyclists and have a feeling of connection with the people they pass. Third, car drivers will generally move more slowly and carefully on urban roads – partly because of the presence of the bicyclists, partly because of the changes in road design that accompanies that increase, and partly because of other road design changes, such as “traffic calming,” occurring as the result of growing demands for bicycle and pedestrian safety.

(Partly because of this push from outside the ranks of professional Transportation Planners, traffic engineers are slowly accepting that most of what they’ve been taught about making high-speed highway travel safer has exactly the opposite impact on local urban streets.  Speed kills.  Being hit by a car going 40 mph –within the 10-mph speed limit leeway of most city streets – will kill a person not in a car about 80% of the time.  Lowering the car speed to 20 mph reduces the risk to 5%.  In an urban street network, 20 mph is a reasonable speed; going faster just makes you arrive sooner at the next red light.)

The broader goal of increased numbers comes from making cities, businesses, college campuses, and entire states more “bicycle friendly” through pursuit of the Six E’s of engineering, encouragement, education, enforcement, equity, and evaluation.  But there are many specifically safety-focused items that feed into that larger program.


When it comes to safety, most people’s first thought is “what can I do?”  And there are some individual actions worth taking.  The League of American Bicyclists and its local affiliates have set up a national program for “League Certified Instructors.”  Almost everyone who takes one of their “Smart Cycling” training programs gains new skills and awareness on how to take care of their bike and ride on either the road or a path.  Bike shops are beginning to stress to bicycle purchasers the importance of doing regular maintenance and daily “ABC Quick Checks” – looking for possible problems with Air pressure, Brakes, Chain system, Quick Releases, and overall functioning or machine and gear.

Bike stores are also becoming more vocal – for both business and safety reasons – about the value of adding a rear-view mirror, front and back blinking lights, and highly visible/reflective clothing to the package for everyday cycling.  Getting bright front lights can tempt urban riders into the belief that they can see holes and debris just as well, and therefore can move just as fast, at night as during the day – which, for many people, isn’t true and should be countered by keeping the lights blinking rather than steady.  The goal is to make sure cars see you coming, not to let you see where you are going – if the street lights aren’t good enough you should simply slow down.

Although bike mirrors always vibrate to some degree, they allow the bicyclist to see cars catching up from behind without turning your head – a safety advantage made much easier if the car’s headlights are on.  And while mainstream cycling will result in the exchange of spandex for regular work clothes, even fashionistas should find ways to include reflective elements on their outfits as well as on their machines – although this, like wearing a helmet, can create the impression that bicycling is an inherently dangerous act, which, in comparison to every other mode of travel simply isn’t true.  (New York’s Transportation Alternatives is sponsoring a “reflective fashion” show as part of its bike home from work party!)


Should, despite these precautions, an accident occur, wearing a well-fitted helmet is a really good idea.  They don’t reduce direct fatalities, which are typically caused by getting run over or directly hit.  However, as discussed in the June’13 issue of Bicycling Magazine, helmets “soften… rare catastrophic blow” and reduce the severity of getting your scalp ripped by the pavement as you slide, but the normal helmet does little to reduce the impact of “more common crashes…at slower speeds but can still result in concussion.”  Lowering (but not eliminating) the likelihood of damaging concussions requires technologies such as the MIPS (multi-directional impact protection system) currently only available in the US on the Scott Lin helmets.

While encouraging helmet use is a proven safety measure, requiring it has the counter-intuitively opposite effect — because there will always be some percentage of people who refuse to wear helmets, mandatory helmet laws cause an immediate and possible long-term decline in the number of people willing to ride, and hence the overall safety of the streets.

Post-accident injury reduction could also come from wearing appropriate clothing, a trick that motorcyclists have learned with their heavy leather jackets and big boots.  The market does not currently supply similarly protective light-weight clothing for muscle-powered vehicles, but the concept isn’t totally impossible.  More immediately, better training among police, ambulance and Emergency Room staff about the most frequent types of bike-related injuries might improve the speed and impact of their efforts.


Changing the bicycling environment will impact more people than efforts to convince every individual to behave differently.  Improving the context requires political or at least collective action because, by definition, it cost-effectively affects everyone – or at least large numbers.  There are several approaches:  training programs integrated into school Physical Education and new driver education programs, changes in mandated equipment on motorized vehicles, changes in road design and other infrastructure, and a wide range of public policies.


In Denmark, bicycle training is an automatic part of grade school, if not pre-school.  This requires making enough bicycles available for Phys. Ed. classes, perhaps on a district-wide rotating basis of 2 weeks per school per year, which should be within the financial ability of most school systems.  And it requires updating Phys. Ed. instructors’ own training, which could be done as part of the current shift from team sports (that only benefits the most athletic among the students) to life-long fitness (that can benefit everyone).

In Massachusetts, the Registry of Motor Vehicles now includes at least one bike-related question on every written driver’s test based on a new section in the driver’s manual about the laws relating to on-road cycling and cars.  But nothing has yet changed in the actual road test.  Furthermore, there appears to be no testing at all for Massachusetts commercial driver license (CDL) applicants about safe operational methods around bicycles, despite the fact that commercial vehicles have the deadliest track record for cyclists.


Being hit by a right-turning car going across a cyclist’s track is the “deadly right hook” bogyman of bike safety.   Once the cyclist passes the vehicle’s rear she can no longer see if the turn signal has begun flashing, assuming of course that the driver turned it on in the first place.  Requiring mirror-mounted blinking turn lights would give the cyclists another chance to notice and take protective action.  Similarly, requiring all cars to have daytime running lights – always lit headlights – makes it much easier for a cyclist to see them approaching from behind either via a bike mirror or by a quick glance.

Colliding with a truck or bus can cause serious injury, but what kills cyclists and pedestrians is having the impact throw them under the rear wheels where they get crushed.  The UK, European Union, Japan, and Brazil all require their trucks to include “side guards” or “lateral protection devices” that protect against this deadly type of collision.  Several US cities, including Portland, have begun installing them on city vehicles.  Costs are estimated at about $500 for a retrofit and much less if factory installed.  It’s a lot less costly than a life and should be made mandatory at least for all new trucks and buses.


As we all know from personal experience, the way we drive depends more on road conditions than posted speed limits.  If there are potholes, bumps, tight corners, or lots of surrounding activity we drive slower.  If there are wide lanes, soft curves, smooth pavement, few distractions, and less traffic we go faster.  Programs such as traffic calmingroad diets, and Safe Routes To Schools have developed ways to make the physical environment encourage safer – and slower – driver behavior.  Traffic planners have begun talking about making road conditions that reflect the “desired speed” for a particular location rather than being enslaved by the “design speed” – which can be measured in many ways but because of the historic tendency to overbuilt roads in highway-like fashion often ends up justifying higher rather than lower limits.

Similarly, the adoption of complete street policies – requiring that designs include multi-modal accommodations – has made it harder to simply ignore the needs of cyclists (and pedestrians and bus riders).  However, simply including bike facilities is very different than making them truly safe, much less prioritizing them over car volume and speed.  The recent Urban Bikeway Design Guide developed by the National Association of City Transportation Officials (NACTO) provides detailed guidance on how to implement state-of-the-art facilities that improve both through-put and safety for all travelers, regardless of mode.

In general, safety is usually increased by either increasing the amount of modal separation or togetherness – it’s the middle situation that’s most risky.  Cycling separation is achieved through the creation of bike lanes, then “protected bike lanes” separated in some visual way from traffic, then “cycle tracks” that are physically separate from cars, and then totally off-road paths which ideally have additional separation between faster moving people on bikes or roller-blades and slower moving people on foot or kids’ scooters and bikes.   A Montreal study found that the injury rate on cycle tracks was 28% lower compared to bicycling on the road, at the same time there was a 2.5-fold increase in the number of cyclists.  A Vancouver study found a nine-to-one increase in safety on the cycle tracks, which were also safer than cycling on an off-road path shared with pedestrians.

Creating bike facilities taps into the latent demand for cycling.  As with highways, if you build it people will come.  (The reverse insight that “if you take it away, they will go away” turns out to be also true – which is why reducing car capacity in favor of transit or bicycling almost never results in the long-term traffic chaos that pundits always predict!)  In the city of Cambridge, the number of cyclists tripled in the ten years after bike facilities began to be widely installed, to the point where several intersections now have “bicycle traffic jams” at rush hour!

The “push everyone together” approach, often called “shared space” may seem counter-intuitive but relies on the insight that the more that people have to pay attention to what they’re doing the less likely they are to do something stupid.  Cars are allowed into a specially-marked “bicycle boulevard”, “neighborway”, “bike priority area”, or “pedestrian/bicycle zone” but the speed limit is no more than 5 to 10 mph and “vulnerable road user liability” rules prevail – meaning that the more damage your vehicle is able to cause the more you are by default responsible for preventing it from happening.  Bicyclists are responsible for keeping out of the way of pedestrians; cars have to go slow enough to yield to all non-motorized traffic; trucks watch out for cars and everyone else.  Not only does this actually work, resulting in significantly lower accident rates for every type of traveler, in some situations it also leads to faster throughput for cars who no longer have to wait for lengthy traffic lights or find breaks in the traffic flow in order to make difficult turns.


In a certain sense, everything connects to policy.  In addition to the previously described policies relating to universal training, motorized vehicle equipment, and road design several other policies would significantly change the traveling environment to enhance bicyclist safety.  Some examples include the passage of Vulnerable Road User Laws not only for “shared spaces” but for all roads, parking areas, and off-road locations – perhaps combined with regulations requiring motorists to keep at least three feet away from bicyclists they pass or to leave their headlights on during the day even if the vehicle doesn’t have automatic daytime running lights.  Banning distracted driving (cell phones or horseplay) by both motor vehicle drivers and bicycle riders would prevent many problems.  Stronger enforcement of existing or newly passed laws governing car movement – speeding, running red lights, parking in a bike lane, making right turns from a left-hand lane (especially for trucks) – would make a big difference.  A London study found that while trucks constitute only 5% of urban traffic they are responsible for nearly 50% of cyclist fatalities.  As a result, some municipalities are now requiring that deliveries be made early in the pre-commuting-time morning, or even banning large trucks entirely from various sections of the city.

In Copenhagen, city officials have decided that providing positive incentives for cycling are not enough.  They have begun exploring ways to actively discourage bringing cars downtown through reduced parking spaces and increased parking fees, lower speed limits, exclusion from various plazas and streets, and other methods.  The high level of car and gasoline taxes as well as the relatively easy availability of public transportation also nudge car numbers lower.

All these policies find a focus in Transportation Demand Management programs that require every employer to analyze staff commuting and customer travel patterns and implement ways to reduce the number of single-occupancy trips.  TDM has played a major role in the city of Cambridge’s ability to lower traffic volume in the Kendall Squarearea by nearly 14% while packing additional firms and employees into more than 4 million square feet of new commercial and institutional space over the past decade.

Finally, providing affordable bicycles to low income families can give opportunity to people who often have few transportation options.  Boston’s “Roll It Forward” bike donation program collects and repairs used bikes then gives them, along with helmet and training, to low-income kids (and their families) around the city.  Their 2013 goal is 2,000 bikes!


As with all public health issues, bicycle safety is partly dependent on larger societal conditions, most directly land-use patterns but also including the level of poverty, the amount of street violence and police tactics, and the larger national response to our escalating environmental/climate crises.

Transportation and land use are intimately entwined.  It was our vast amount of land that made the Interstate highways seem fitting; it was the highways that made the dispersed suburbs possible; it was the low-density suburbs that made cars indispensable.  Smart growth and the “new urbanism” seek to create more vibrant, appropriately dense, mixed-use communities where residents can easily walk or bike between home, work, school, daily shopping, friends, and recreational activities.  As real estate agents already know, people prefer to live in walkable and bikeable communities or near bike paths; customers will pay more for products bought in stores on tree-lined streets. Changing zoning patterns to a “form based” approach with appropriate types of business and residential uses, requiring significant moves towards more “energy positive” structures and vehicles, and ensuring that people of all income levels and races are welcome – along with robust infrastructure for non-motorized movement — will create neighborhoods where bicycling and walking are both common and safe.

The more seriously our nation deals with the need for energy conservation, greenhouse gas emissions, and declining fossil fuel reserves, the higher priority will be given to expanding our mass transit, bicycling, and walking facilities.

As with nearly all public health and cultural issues, reducing poverty will also have a positive effect.  Getting on a bike requires not only the purchase of the equipment and the acquisition of skills, it also requires a certain amount of social confidence.  People who think it likely that they will be mistreated should the police have reason to notice them, as many poor or non-whites have historic reason to believe, or who don’t trust that other members of society will be sensitive to their well-being, are less likely to bike on the road or anywhere else.  Similarly, people who live in violent neighborhoods are unlikely to allow their children to play outside, much less to be seen with a desirable object.


In any context, it is the individual bicyclist’s responsibility to use appropriate equipment, and ride in ways that prevent injury to both herself and others.  But there’s only so much one person can do.  Individual change sets the stage for large scale transformation, but it neither triggers nor implements it.  Big changes require advocacy – the careful combination of protest, lobbying, and partnership that leverages the impact of organized groups.  If you really want to be safe on your bike, spend more of your days cycling and more of your evenings joining others.   Enjoy the ride!


 Thanks to Charlie Denison, Carice Pingenot, Laura Smeaton, and especially Alex Epstein for feedback on earlier versions.


Related Previous Posts:

NON-MOTORIZED HIGHWAYS: A Regional Green Routes System To Connect Municipal Bike Networks, Sidewalks, and Parks

MODE SHIFT AMPLIFIERS: The Importance of the Out-of-Vehicle Experience

MAKING COMM. AVE. SAFER: City Proposals Are A Good Start; TurnPike Overpass Is Next Issue

ROAD RAGE, GUNS, & DEMOCRACY: Why Road Safety is About More Than Traffic Lights

MOTIVATING HELMETS: How Convince People To Buckle Up

SAFETY AND THE LAW: When Are Higher Penalties The Right Tool For Changing Behaviors

ZONING REFORM: Unlocking Investment in Transportation, Health, and Livable Communities

SHAPING TRAVEL CHOICES: The Four C’s of the Behavioral Context

SAFE CYCLING – Actual, Subjective, Social; Solo or Group



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