ENOUGH KILLING: How to Make Bike-Car Collisions Less Deadly

It’s important to know that the huge increase in bicycling in Boston has been accompanied by a much small increase in bike-car collisions, meaning that the accident rate has gone down.  It’s yet another validation of the “Safety In Numbers” principle.  It’s not that the new cyclists are more skilled than the previous ones, or that a higher percentage of them are wearing helmets. It’s simply that the more people on bikes the more that drivers become aware and accepting of their presence, leading to a lower rate of collisions and injuries.

But that doesn’t make it any less upsetting to learn that yet another bicyclist has been killed by a motor vehicle.  The fifth this year.   Yet another ghost haunting our streets.

The police haven’t issued a final report on this latest tragedy, so the following is based on what has been available in the newspapers and on-line.  But here is my best guess of what happened, and some suggestions about how to make it less likely to happen again.


Twenty-three year old BU graduate student, Christopher Weigl was cycling down Commonwealth Avenue on his way to class.  It’s a down-hill grade in that area and the light ahead of him was green.  If he did what most people (including myself) do in that stretch of road, noticing that none of the cars in the lane immediately to his left had their right-turn blinkers on, he sped up as he approached the intersection.

The tractor-trailer driver, working for an out-of-town firm, was also coming down Commonwealth and getting ready to make a right turn on to St. Paul street.  He was in the far-left lane because the size of his vehicle required a large turning radius.  Knowing that his turn would block both car lanes, and noticing a break in the traffic, he pulled a sharp and quick right.

Even if the truck had its turn blinkers on, it’s unlikely that Weigl could see the truck coming from two lanes to his left.  Even if he thought to look (and could see) over the cars on his right  it would also be difficult for the truck driver to notice a fast-moving cyclist who probably was still a  hundred feet or more before the intersection when he turned his wheel and hit the gas.

By the time Weigl saw the truck in front of him it was too late.   News reports say that we was wearing a helmet, but it wouldn’t have mattered – it seldom matters in a collision drastic enough to kill.  It’s not clear if Weigl was instantly killed by the impact or fell under a wheel before the driver could stop, which is the usual cause of death when someone is doored and is then thrown outwards into the street – which is what happened a couple years ago to a young women in Cambridge’s Central Square and may be what happened to the cyclist killed earlier this year in South Boston.


There are a couple of possible preventive lessons in this.  Yes, cyclists should be very careful when approaching intersections – you may be dead right, but you’re still dead.  But that’s not the real issue here – no one was acting illegally or irresponsibly or stupidly.  Everyone was doing what they were supposed to;  and someone died.

First, the city and state should enforce the law forbidding two-lane right turns.  They’re simply too dangerous – accidents waiting to happen.  If the intersection isn’t big enough for a tractor-trailer to make a one-lane turn, then they shouldn’t do it – and neither should car drivers no matter what their turning radius.  (And this is yet another good reason to start installing intersection cameras!)   A more drastic approach would be to ban 18 wheelers from the city either all the time or during certain hours. Deliveries should be done with smaller box trucks. They are not only safer when moving but take up less curbside space. This is what they do in bike friendly cities in Europe.

Second, to prevent under-wheel killings, the state should require all large trucks, tractor-trailers, and buses to have “side guards.”   These are railings or flat sheets between the wheels that both save fuel by making the truck more aerodynamic and save lives by preventing bicyclists, motorcyclists, scooter-riders, and pedestrians from sliding under the wheels.   They’re expensive,  costing $800 to $2,000 to install.  On the other hand, they work:  side guards have been mandatory in Europe since 1989;  after Britain adopted a side-guard requirement one study found that fatalities dropped 61% in cases where bikes collided with the side of the truck.  It all depends on your priorities.

Portland, Oregon now puts side guards on all municipal trucks.  Since the purpose is to prevent people from getting swept under the wheels, something that almost exclusively happens when the driver is turning right (partly because the driver is less able to see what’s approaching from the right than from the left) , the city only places them on the right side of the truck.  In Canada, Newfoundland and Quebec have put side guards on their government-owned truck fleets.  (British sites provide technical details about fitting side guards on various types of trucks, including retractable side guards for trucks that get tipped,  e.g. dump trucks, or those that drive over extremely uneven surfaces, e.g. logging trucks.

Third, we have to lower speed limits and build our new expectation into the very structure of the road.  A car going 40 mph has an 80% chance of killing anyone it hits.  Reducing the speed by half decreases the likelihood of death to 5%.   Dense commercial and residential areas should have a default limit of 20 mph – or less.  Walk Boston and other advocacy groups are working on a bill to do this on a state-wide basis.  Defining the street segments to be affected and how to measure speed violations turns out to be very difficult, but when the final wording is determined we all need to support it.  In addition, we need to give municipalities the right to create “Safety Zones” around not only schools but also parks, playgrounds, senior centers, and health care facilities with speed bumps that make it uncomfortable to drive faster than 15 miles per hour.

Fourth, Complete Streets are not enough – unless the program mandates more protected bike lanes along major roads or turns certain streets into “bicycle boulevards” with special bike-prioritizing traffic signals at intersections.   This would not only provide a lower level of traffic stress, thereby inviting lots of additional people to try bikes and playing into the Safety In Numbers dynamic, but make it more likely that right-turning car (and truck) drivers would actually see cyclists.

Even better would be the creation of a cross-town series of bike “corridors.”  These would be composed of off-road paths through our parks (like the ones in the Emerald Necklace) or along our waterways (like the ones along the Charles and Neponset rivers).   They would include separated-from-traffic protected bike lanes – set up using painted lines, flexible buffers, or well-placed parked cars (as already exists on Western Avenue heading towards the Charles River), or even curb-separated cycle tracks (such as those being proposed for Melnea Cass and Malcolm X Boulevards).  The Corridors could also include low-traffic, usually residential “neighborways” which have been specially signed and shaped to keep cars at a low, child-safe speed.  And they could have some sections of “Bicycle Boulevards” which are larger, longer stretches of road that have been restructured to prioritize bicycle travel (such as might be possible along one side of upper Commonwealth Avenue).

At a minimum, all of DCR’s Parkways should be restriped to create buffered bike lanes.  This would also be fitting because, in the best of all possible futures, the Corridors would be treated like extensions of our parks into our neighborhoods – tree-lined, with water-runoff catchments, and occasional play spaces for local children to use, which is why those of us working for this vision describe it as a Green Routes system.

None of this will bring back Weigl or the other four cyclists killed by cars, trucks, and buses.  But it may reduce the number of future deaths.   We’ve got enough white bicycles.


Thanks to Alex Epstein for the side guard idea and Charlie Denison for suggesting the truck ban.


Related Previous Postings:

> VULNERABLE ROAD USERS (VRU) PROTECTION LAWS: “Whoever Can Do The Most Damage Has To Be The Most Careful”


> GREEN ROUTES TO THE FUTURE: Combining Regional Vision and Local Initiative to Revitalize Urban Transportation and Well-Being

> PARKS, GREENWAYS, AND TRANSPORTATION: Increasing Usefulness By Combining Visions

> SAFE CYCLING:  Actual, Subjective, Social; Solo or Group





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7 Responses to ENOUGH KILLING: How to Make Bike-Car Collisions Less Deadly

  1. Daphne says:

    Very good description of what probably happened and how to avoid it in the future — but can we really say “everyone was doing what they were supposed to do”? Sure, it’s hard to see a bike that is two or three lanes to the right and several hundred feet back, but if you can’t see that your way is clear then you should be waiting, or moving slowly, until you can confirm that your way really is clear. Wouldn’t it have been wiser for the truck driver to turn slowly and be sure that his maneuver was safe, even at the cost of making some cars (and indeed bikes) slow down? You’d have to ask a lawyer whether this action rises to the level of criminal negligence, but if your supposition about the sharp and quick right turn during a supposed break in the traffic is right, I think it does.

    Look, I yield to cars that are turning right in front of me a lot, because I’d rather be alive than “dead to rights.” But a mediagenic tragedy like this could have been an occasion for educating the driving public about the MA right hook law, which many drivers don’t know about.

    It’s terrible to think about this tragedy as an “opportunity,” but this is the first time in ages that I’ve seen drivers (as opposed to bicyclists) thinking about road safety. There are some comments on related news stories written by drivers wondering “who has the right of way when I’m turning across a bike lane”–I had always thought that the drivers who right hook me were either jerks or blind, but it turns out that some of them are just ignorant of the highway code. Doesn’t make me any safer or any more trusting, but at least ignorance can be fixed more than “being a jerk” or “being addicted to your cellphone” can. Now that’s a public health campaign I’d like to see, instead of “No Excuses/Wear A Helmet.”

  2. semiller says:

    Thanks for the comment. I actually thought several times about the “doing what they were supposed to” phrase. I was trying to emphasize that no one was acting in a totally outrageous manner. Of course, in hindsight it’s clear that the truck driver should have been more careful. And I suspect that the driver — like all drivers who let themselves be vulnerable and open enough to internalize the lessons of that horrible incident — will be more careful in the future. But putting myself into that moment, assuming that the cyclist was a hundred feet or more away from the intersection at the moment of beginning the turn, I can’t say that I would have done so much better — I would hope I would, but I can’t be sure about it. Some drivers, like some people (including bike riders) are simply jerks. But most, like most people, don’t intend to be hurtful. And I agree — “look right” would be a better focus for a public health campaign than “wear a helmet.”

  3. terry says:

    BOTH “doing what they were supposed to”, is what I tried to fathom on Dec 23 when I chose to ride the down hill section of Comm. Ave.

    The common practice’s by both truck drivers and cyclists at that particular intersection absolutely needs to be re-examined and re-mediated.

    Most educated and experienced motorists/cyclists know that just before a truck takes a right turn , not to squeeze by on the right. I think experienced motorists and cyclists will agree that the situation that day on Comm Ave invites ambiguity and demands extreme levels of awareness and caution.

    What the truck driver appears to have done is get into the furthest left lane, long before the intersection. For all Chris new , that truck driver was getting situated for a left turn. The truck drivers choice, way before the intersection, is ambiguous at best. I would guess that nine out of 10 car drivers in right lane would have been surprised by that lane position of the truck driver.

    Please read this post from a cyclist last year, titled

    # Rear-ended on 15 Nov 2011 at 7:30 pm

    i was ran over by a woman while riding my bike yesterday. i was in my lane and moved over just a smidge to make a banking right hand turn. she thought i was going left and soon as i moved over went to pass me. she following way to close and i actually turned into her not realizing she was right there as she should have waited till i was more than finished with my turn to speed up. her trailblazer sucked my bike under the front wheel and she ran over my foot. think again when you think about passing too closely to a bicyclist. im about to go after her for my extensive hopsital bills..

  4. semiller says:

    I agree that most of us know that it is really dangerous (and stupid) to try to squeeze by on the right just before a truck (or any vehicle) takes a right turn. In addition, I wasn’t there and certainly don’t claim to know exactly what happened but I think you’re right in thinking that Chris had no perception that the truck was turning to the right given its left-lane position….a confusion that the earlier post shows happens no matter what vehicles are involved…meaning that Chris wasn’t trying to squeeze by: he thought he was going straight in a situation that posed no danger. So the bottom line is both that we all have to be more careful at intersections no matter how safe they may appear to be AND we need to find ways to reduce the probability that cyclists (and pedestrians) get injured (killed) by getting thrown under the wheels of trucks, buses, and cars. Steve

  5. terry says:

    .”July 8, 2002
    News Release: Fatal crash could have been easily avoided.
    Government miseducation an ongoing problem
    CAMBRIDGE – The recent fatal bicycle crash of 36-year-old Dana Laird could have been easily avoided, had she followed the published advice of a local bike safety expert.
    But the Cambridge city government gave her the opposite advice, with tragic results.
    “Dana Laird was killed because she rode her bike in the ‘door zone,’” said John S. Allen of Waltham, engineer and author of numerous cycling books and articles, and co-founder of the Cambridge Bicycle Committee 16 years ago. “For decades, we’ve told bicyclists to ride their bikes outside of the door zone. And if they follow that advice, they won’t get ‘doored.’ [struck by a car door flung open]”
    Allen spelled this message out in his booklet Bicycling Street Smarts, which has been adopted by the Departments of Transportation in Pennsylvania and Ohio as the official bicycle driver’s manual. Here’s what those states tell bicyclists about the door zone:
    Where there are parked cars, the usable width of the street begins about 3 feet out from them. . . Don’t ride in the danger zone. . . . At speeds above 5 miles per hour, you can’t stop in time to avoid a car door. Then your only choices are to hit the door or to swerve out into the street—maybe into the path of a passing car. Avoid this problem by riding outside the reach of car doors. (Chapter 2, Page 13, Ohio Bicycling Street Smarts)I was writing government guidelines about avoiding the door zone 24 years ago. We are supposed to know better. Door zone bike lanes are a sad example of government that won’t admit its mistakes.”
    Allen pointed out that most bicyclists need “permission” to ride outside the door zone, and a bike lane in the door zone seems to withdraw that permission.
    “Every vehicle operator has the right to operate his or her vehicle in a manner consistent with his or her own safety,” Allen said. “And a bicyclist is a vehicle operator. A bicyclist shouldn’t cringe to the right for the convenience of overtaking traffic, any more than a minivan mom should whenever a sports car appears in the minivan’s rear view mirror.
    “For decades, we’ve been teaching bicyclists to ride confidently and safely, with great results. But we can’t teach everyone. And our efforts to make safe cycling practices into general knowledge are thwarted when the government paints a bike lane in the most dangerous place.”
    Years earlier, Allen had pointed out a study that found a high rate of dooring collisions in the Boston area to the Cambridge city government, together with a plea to avoid “door zone” bike lanes and a safer alternative plan. His plea was ignored.
    “I know all too well the desire to ‘do something’ for bicyclists,” Allen said. “And when you paint a bike lane, it’s a highly visible ‘something.’ That doesn’t make it right. Sometimes, doing nothing is best. Sometimes, a different accommodation is the safest.
    “A bike lane in the door zone is never safe. I told Cambridge that years ago, and now I’m sorry to have to repeat the message.”
    Schubert added that he’s seen “too much creativity” from planners and designers anxious to make their mark on the world.
    “Traffic engineering isn’t a game,” Schubert said. “If you screw it up, people die.”

  6. terry says:

    I started a perceptual analysis of a Dec 6 bike fatality on Commonwealth Ave across the street from Boston University. Cyclist was riding in a bike lane on a downhill section of a bike lane .One witness (Rebecca Albrect) claims the left side of DZBL is wavy. If true, I assume it is causally related to bus and truck weight and use of that side of DZBL.

    Vehicular cyclist’s might know to leave the DZBL (door zone bike lane) and claim a smooth section of the adjacent lane. That perfect version of cyclist with proper traffic attention, would also be more at liberty to maintain speed AND have the time to switch between “open focus”(where conscious attention to peripheral risk is knowingly sought) to “narrow focus” (which is like tunnel vision) but necessary to correctly asses the greatest risk at any given moment.

    My assertion is that beginner to intermediate cyclist’s, with “partial information about dangers of riding in bike lane” (ie being advised of the primary danger of being door’d) would, on that down hill section, be hyper-vigilant to only one risk. Narrowly focused on a heightened risk of being door’d. IN THIS CASE FATALLY STUCK in a narrow focus mode sequentially scanning each and every door and driver seat, that there would be very little left in their ability to decipher the lethal semi-truck positioned illegally two lanes to the left about to take an illegal right turn.

  7. semiller says:


    I have no interest in providing a venue for the remnants of the vehicular/effective cycling partisans to rehash their complaints. The election is over — they lost. At the same time, I acknowledge that they have some important ideas about how to safely cycle in traffic. So…

    1) I just walked along the stretch of Comm. Ave where Christopher Weigl was run over. The pavement along the left side of the bike lane IS a little bit uneven (“wavy”), which might have pushed him a bit further to the right where he would have been paying extra attention to the possibility of someone opening a car door. It’s possible that this prevented him from noticing that the truck was quickly (and illegally) cutting across two lanes of traffic to make the right turn.

    2) The right line in a bike lane is more about keeping parked cars close to the curb than providing a suggestion path for cyclists. Because of this, the right side of a bike lane is often within the door zone. The left line of a bike lane is what cyclists should use as their guide.

    3) The danger posed by cars and trucks, the inability of non-highly-fit cyclists to keep up with moving traffic, and the unwillingness of non-high-risk bike riders to place themselves in the middle of moving traffic makes most bicyclists hug the right side of the road. We can either tell these people that they are unfit to be cyclists and they should leave their bikes at home, or we can find a way to make our roads safer for them without demanding that they act contrary to their core feelings. Given that the most important factor in lowering the rate of accidents (for both bicyclists and car occupants) is increasing the number of cyclists on the road, thereby making motorists more aware of their legitimate presence and (to some degree) slowing them down, it would seem that the second strategy is better for everyone.

    3) Based on months of filming bicyclists and then measuring both the cyclist’s distance from parked cars and passing cars distance from cyclists, the city of Cambridge found that painting an “edge line” then adding bike symbols, then adding an outside line to create a bike lane each increased the distance that bicyclists rode away from parked cars AND the distance that passing cars were away from the cyclists. Furthermore, “When motorists were asked what made them most aware of cyclists on the street, the most common response during the “before” condition was ‘nothing.’ In the ‘after’ survey, the most common response was ‘the bike lane.’” (See Bike Lane Study: How Pavement Markings Influence Vehicle)

    Now, let’s make the city safe for bicycling for ordinary people — lots of them!

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