Category Archives: Crashes

Description and history of the location of the Tempe crash

Comments from Reed Kempton, a Senior Planner with the Maricopa County Department of Transportation, late in the day on March 21. This is an addition to my earlier post about the crash. I thank Reed for his permission to post his comments, which originally appeared on the e-mail list of the Association for Bicycle and Pedestrian Professionals.

**********

I’ve been driving through this intersection in its various configurations for 50 years and bicycling here for 48 (Yes, I am that old!) and would like to address some of the questions and statements from the past couple of days. Refer to the Google link below and note the position of the large X in the median. One report indicated that the pedestrian stepped off the median into the car’s path about 350 feet south of the intersection near the top of the X in the northbound direction. If this is the case, the car would have just changed lanes and been moving into the left left turn lane. 125 feet further south makes more sense to me as the car would be moving straight and not yet reached the left turn lanes.

https://goo.gl/maps/YkNMUu1nYZp

>How many lanes of car traffic are there?

2 lanes southbound; 2 lanes northbound; approaching the intersection northbound adds 2 left and one right turn lane; both directions include sidewalks and bike lanes

>Why does the area have clear, solid, inviting pathways across a median, if people aren’t supposed to cross there?

A history on the Mill Avenue bridges over the normally dry Salt River can be read at the Wikipedia link below but here is a short summary. From 1931 to 1994, only one bridge existed. Southbound traffic used the bridge while northbound traffic drove through the river. When water was flowing, a rare occurrence for many decades, the bridge was used for one lane of traffic in each direction. There was an asphalt crossover located just north of the bridge. When the second bridge was added, a crossover was put in place to accommodate the potential closing of one of the bridges. The X in the median is intended to be used to move cars from one side to the other if a bridge was closed. What looks like a path, has vertical curbs and signs that say do not cross here. In 1999, Tempe put two dams in the river to create a town lake.

https://en.wikipedia.org/wiki/Mill_Avenue_Bridges

>How far is it to a safer place to cross?

The signalized intersection is 350 feet north. Ped access to the park below the road is about the same distance south. Just south of that is a shared use path along the north bank of the river. The Rio Salado Path connects to path systems in Scottsdale, Mesa, and Phoenix making it possible to travel significant distances without riding or walking on a road.

>A trail meets the street where there is no crosswalk and no traffic signal.

While it is pretty easy to walk across the desert landscape in this location, there is no trail meeting the street. There are numerous mountain bike trails east of Lake View Dr.

Maybe tomorrow we will be given more information.

Reed

The Tempe crash

The dashcam video in the recent Tempe crash which killed a woman walking across the street with a bicycle has now been released.

To me, it is quite clear that the human driver was dozing off or distracted and that the vehicle’s sensors failed to register that the pedestrian — walking with a bicycle broadside to the road, a very robust infrared and radar target, and crossing empty lanes before reaching the one with the Uber vehicle — was on a collision course. The vehicle had its low-beam headlights on when high beams would have been appropriate, the headlights were aimed low (probably a fixed setting), and the pedestrian’s white shoes don’t show in the video until two seconds before impact, that is, at a distance of about 60 feet at the reported 40 mph.

Braking distance is about 80 feet at 40 mph, and reaction time for a human driver adds about another 60 feet. An automated system with radar and infrared should have noticed the pedestrian sooner, had a shorter response time, and stopped the vehicle. Human eyesight is much better than a dashcam’s at night and the human driver might have seen the pedestrian earlier and avoided the crash if she had been paying attention. But also, the bicycle had no lights or side-facing retroreflectors which might have shown up much earlier and alerted optical or infrared sensors or a human driver, and the pedestrian somehow chose to cross an otherwise empty street at precisely the time to be on a collision course.

So, the human driver and vehicle’s sensors failed miserably. We can’t allow automated vehicles (and human drivers) to perform at the level shown in this video. We do need to make greater allowances for pedestrians, bicyclists, animals, trash barrels blown out into the road, etc.

Several people have offered insights — see comments on this post, and also an additional post with a description and history of the crash location.

Avoiding the left cross

This post isn’t about pointing the finger of blame. If that is to your taste, you can find endorsement of that position in many of the comments on the video on YouTube. But I think that we would rather avoid crashes in the first place, so this post is about avoiding crashes.

The cyclist could have prevented this crash. He missed three cues that it was about to happen. The motorist missed one cue.

Briefly at 0:09 through 0:10 in the video, the car which was about to turn left is visible with its left-turn signal on. The cyclist’s camera saw the car and so the cyclist also could have seen it and the motorist could have seen the cyclist, but neither was looking at/for the other. The car slowed (note increasing gap between it and the SUV ahead of it). The minivan which the cyclist was passing on the right also slowed, leaving a gap for the car to turn left into the driveway. These were additional cues which the cyclist might have heeded. Following the brief interval when the cyclist and motorist might have noticed each other, the minivan screened the cyclist’s and motorist’s view of one another until too late for either to prevent the collision.

How might cyclists avoid crashes like this? While it is tempting to maintain speed in a bike lane when motor traffic to the left is slow or stopped, do not expect that the bike lane somehow makes you immune to incidents like this. Do not pass on the right any faster than would allow you to avoid a vehicle or pedestrian crossing in front of the vehicle to your left. If you can safely pass motor vehicles on the left (though not here on this two-lane road), do that instead.

Alice Swanson fatality, a right hook

Here is the intersection in Washington, DC, where cyclist Alice Swanson was killed by a right-turning garbage truck.

The Street View is from 2009, as close as Google gets to the year of the crash (2008). The big cross street is Connecticut Avenue. The little one before it is 20th Street NW. My recollection is that the garbage truck turned right into 20th Street, and Swanson probably assumed she could pass it safely because it would turn right onto Connecticut Avenue and the traffic signal was red. If you open the Street View in Google Maps and click on the clock at the upper left, you can go to Street Views from different times and see the intersection without a bike lane (2007) and with green paint (2014). The dashed bike lane stripes indicate that motorists are supposed to merge into the bike lane, but many do not and it may not even be possible with a large truck. Note also that parking extends close to the intersection — the last 20 feet or so are no parking, with a fire hydrant.

Duck Boat crashes

We had a duck boat run into a motor scooter from behind on Saturday, May 7, 2016 in Boston, killing one of the riders. It isn’t clear from the news story why this happened, though I expect that the poor forward visibility from the duck boat was a factor. Did the motor scooter operator pull ahead of the duck boat, riding and stopping in its large blind spots? Or did the duck boat operator run into the back of the motor scooter in spite of its being in hiss field of view? As usual with crashes involving two-wheelers — bicycle, motor scooters, motorcycles — and despite there having been many eyewitnesses, the Boston Globe offers no information as to the cause of the crash. Investigation is underway, although if it proceeds as with recent bicycle crashes, detailed results may not be made available for a long time, if at all.

Another duck boat crash occurred in Seattle, 5 killed, 62 injured — but that one was due to failure of an axle, which sent the duck boat into the side of a bus in an oncoming lane of traffic.

What is to be learned from these crashes?

For one thing, the duck boats are surplus from the Second World War. Though they served gallantly in that war, they are over 70 years old now: mechanical failures are not out of the question. The duck boats’ design as amphibious vehicles placed the driver high above the road over a high hood, with poor visibility to the front — a problem which has led to fatalities of pedestrians in crosswalks with large trucks. The duck boats do not have a front bumper, but instead, have a hull which can push unfortunate pedestrians, cyclists and vehicles underneath. These vehicles probably would not be legal, except that they are antiques.

Another issue with the Boston crash may be of education. Did the motor scooter driver not understand the peril of riding in blindspots of large vehicles? Boston is relentlessly installing bicycle facilities which direct bicyclists to ride into blindspots. It does not appear that the collision involved any such installation, but motor scooter operators are permitted under the law to use them, and their existence, along with a lack of instruction as to their perils, contributes to hazardous behavior elsewhere as well.

In the context of all these issues, my misgivings about the Vision Zero campaign described in the Boston Globe on April 17 need no further mention.

Some thoughts about self-driving cars

Google’s report on its self-driving cars:

http://static.googleusercontent.com/media/www.google.com/en/us/selfdrivingcar/files/reports/report-0515.pdf

Most than half of the collisions reported in this document are slow-speed rear-enders of the Google cars. That’s unusual. It might be that the behavior of the Google cars is more cautious than what human drivers expect, so the Google cars stop more often abruptly or at unusual places, and so are not tailgater-friendly. I’d suggest that the Google cars might be equipped with a rear-facing warning device.

It seems to me that self-driving cars will be able to avoid any collision where a human driver could avoid fault, and others. In other words, operators of non-automated vehicles (including bicycles) and pedestrians who follow the conventional rules of the road will be able to operate safely around automated vehicles. Vehicles with automated crash avoidance (not necessarily completely automated vehicles, even) will not rear-end bicycles, and so the premise of fear from the rear evaporates if automated crash avoidance becomes universal with motor vehicles. Self-driving cars will not be able to avoid collisions where avoidance would require violating the laws of physics. Vehicles with automated crash avoidance will be able to avoid some collisions in which the potential colliding vehicle or pedestrian is outside the field of view of a human driver, such as right-hook collisions, as long as there is a clear sight line to the automated vehicle’s sensor. Same for a large truck’s high hood which prevents the driver from seeing a pedestrian crossing in front.

Automated vehicles will not be able to avoid left-cross collisions where the bicyclist or motorist is passing on the right of other vehicles and concealed by them, or pedestrian dart-out collisions. The concept of fully networked vehicles is supposed to address this problem. All vehicles approaching the same place in the road network are envisioned as communicating with each other even when they are hidden from each other’s view. As someone with an electrical engineering degree, I consider this at best a very difficult proposition, and it might be described as a pipe dream. Bandwidth, interference and reliability issues lead me to ask “what could possibly go wrong?” Also, instrumenting every object on the road is only practical on a limited-access highway — no, not even there, because there will still be breakdowns, wild animals, debris. On other roads, is every pedestrian going to carry a transponder? I don’t think so.

Automated crash avoidance is easily hacked by rolling a trash can out into the roadway, and the like. The caution which automated crash avoidance inherently incorporates changes the dynamic from the one among humans, which can involve a game of bluff. To me, this means that automated vehicles will be extra-cautious in the presence of other drivers and pedestrians who do play the game of bluff, and so the progress of automated vehicles will be slow and erratic in, for example, Boston traffic.

All this leads to the question: does behavior change as these vehicles become more common? Does infrastructure change? Every new technology takes a while to find its feet. As Marshall McLuhan said, “We look at the present through a rear-view mirror. We march backwards into the future.” Do conditions become better or worse for bicyclists and pedestrians? And why? We have some control over this depending on the direction which is set for the technology, but also, time will tell.

Another serious issue I’ve heard mentioned is the car which is not only driverless but passengerless. There is potential for an increase in traffic if a car can be called to meet a person (like a passengerless taxi), or directed to drive around and around the block empty when a parking space can’t be found. I can’t say how serious this problem will be. To some extent, that depends on the extent of freedom afforded to people’s control over the driverless cars. It’s an interesting legal question involving private use of public space. We already face this question with congestion-pricing schemes. But on the other hand, fewer cars on the road might be needed, because the car-sharing model works better when a car can be called rather than only stationed. Again, time will tell.

Translation of complete paper on German bikeways 1897-1940

I’ve prepared a full translation of the important paper by Dr. Volker Briese of the University of Paderborn in Germany about the history of German bikeways from 1897 through the start of World War II. This has previously been available only in German, or in a highly condensed version in English in the narrowly distributed Proceedings of the 1993 International Cycle History Conference. You may read the English translation here, and also find your way to the other versions as well if they are what you would prefer.

Truck side skirts: reliable way to prevent cyclist fatalities?

No, not reliable, though some are better than others. And they are also supposed to confer an aerodynamic advantage. Some do, some don’t.

Some have a smooth surface which can deflect a cyclist. That is still no guarantee that the cyclist will escape serious injury or death. Other side guards are only open frameworks which can catch and drag a bicycle. A lot of what I have seen is little more than window dressing.

The side guard in the image below from a post on the Treehugger blog has no aerodynamic advantage and could easily guide a cyclist into the rear wheel of the truck.

Photo of truck side with guard from Treehugger blog.

Photo of truck side with guard from Treehugger blog.

A cyclist can easily go under the side guard shown in the image below, from a Portland, Oregon blog post. A cyclist who is leaning against the side guard is guided into the sharp edge of the fender bracket and fender, and the front of the turning wheel, which can pull the cyclist down. There is another wheel behind the one in the photo.

Side guard on City of Portland, Oregon water transport truck

Side guard on City of Portland, Oregon water transport truck

The side guard on a Boston garbage truck in the photo below — my own screen shot from the 2013 Boston Bikes annual update presentation — is only an open framework which could easily catch and drag a bicycle.

Side skirt on City of Boston garbage truck

Side skirt on City of Boston garbage truck

A truck which is turning right off-tracks to the right. A cyclist can be pushed onto his/her right side, and goes under, feet to the left, head to the right. On the other hand, if an overtaking truck contacts the left handlebar end, or if the right handlebar end contacts a slower or stopped vehicle or other obstruction, the handlebar turns to the right and the cyclist slumps to the left, headfirst.

To be as effective as possible for either aerodynamics or injury prevention, side guards must cover the wheels. Though that is practical, none of the ones shown do.

But no practical side guard can go low enough reliably to prevent a cyclist from going underneath. The side guard would drag  at raised railroad crossings, driveway aprons, speed tables etc. Even if the side guard did go low enough, it would sweep the fallen cyclist across the road surface, possibly to be crushed against a parked car or a curb.

Fatalities have occurred when cyclists went under buses, which have low side panels — but the wheels are uncovered. The Dana Laird fatality in Cambridge, Massachusetts is one example. Ms. Laird’s right handlebar end is reported to have struck the opening door of a parked vehicle, steering her front wheel to the right and toppling her to the left.

Dana Laird fatality, Cambridge, Massacchusetts, 2002

Dana Laird fatality, Cambridge, Massachusetts, 2002

The bicycling advocacy community, as shown in the blog posts I’ve cited, mostly offers praise and promotion of sub-optimal versions of side guards, a measure which, even if executed as well as possible, offers only a weak, last-resort solution to the problem of bus and truck underruns.

Most of the comments I see on the blogs I linked to consider it perfectly normal for motor traffic to turn right from the left side of cyclists, and to design infrastructure — bike lanes in particular — to formalize this conflict. The commenters also would like to give cyclists carte blanche to overtake close to the right side of large trucks, and place all the responsibility on truck drivers to avoid off-tracking over the cyclists.

Cyclists are vulnerable road users, but vulnerability is not the same as defenselessness. It is rarely heard from today’s crop of bicycling advocates, but a cyclist can prevent collisions with trucks and buses by not riding close to the side of them. There’s a wild contradiction in playing on the vulnerability, naiveté and defenselessness of novice cyclists to promote bicycle use with measures — particularly, bike lanes striped up to intersections — which lure cyclists into a deathtrap. Regardless of whoever may be held legally at fault in underrun collisions, cyclists have the ability to prevent them, and preventing them is the first order of business.

Want to learn how to defend yourself against going under a truck? Detailed advice on avoiding bicycle/truck conflicts may be found on the CyclingSavvy Web site.

Additional comments about the political situation which promotes underrun collisions may be found on the CommuteOrlando site.

Ian Cooper comments on the C&O Towpath

Cyclist Ian Cooper offers a report on the C&O canal towpath, which I have mentioned in a previous post. Supreme Court Justice William O. Douglas deserves a lot of credit for preserving the canal as a park, but as Ian reports, it does not make the grade as a bicycle facility.

Ian Cooper with Trail-a-Bike rig on the C&O towpath trail

Ian Cooper with Trail-a-Bike rig on the C&O towpath trail

Aside from the issues of safety and of priorities which Ian raises, do the parts of the path which are “paved” with pebbles the size of golf balls meet the National Park Service’s criteria to prohibit cyclists from parallel roads, introduced into the current transportation bill in Congress?

An article in the Pittsburgh Tribune-Review newspaper seconds some of Ian’s comments, while indicating that improvements are in the works. The effectiveness of the improvements is certainly open to question: more gravel will not eliminate dropoffs or necessarily provide a good or durable riding surface. The article includes the photo below.

Rough conditions on the C&O towpath trail

Rough conditions on the C&O towpath trail, Paul Christensen photo for the Tribune-Review

An online article by a bicycle tourist also reports some difficult conditions on the trail.

Ian says about that article:

The first image on the left of the page shows a little of how muddy it can get, though it can be worse than this when the path gets very narrow and bumpy. This is a different area of the trail (farther north than my ride), and again this is very wide and non-grassy in comparison with some of the trail south of Harper’s Ferry and Point of Rocks, MD. The author tells how safety is a real issue on the trail due to the bad condition of the surface.

In both the above images, the wide trail allows you to choose a path through the mud. This isn’t always the case in the part my daughter and I cycled. Sometimes you just have to stop and walk. Sometimes you get no warning, hit a pothole or a mud patch and have to rely on skill to maintain control.

Here are Ian’s comments on his own ride:

I know the C&O well. Here on the Maryland side it’s not paved, and I think anyone doing more than 10 mph on it would be taking a grave risk. I cycled with my daughter from DC to Harper’s Ferry June 2nd – 3rd, 2011 with my daughter on a Trail-a-Bike behind me. I will never use it again, as the National Park Service has stated that it must remain unpaved, as it is to retain its historical attributes as a canal towpath. The only reason I didn’t give up on using it during that trip is that I have a lot of experience cycling in winter conditions, so I had confidence that I could counter-steer and retain balance during times when the bike lost traction in the mud. Also, we were heading north, so we were cycling on the canal side of the trail, where the drop-off was only 10ft. I dread to think what might happen if a less confident or less skilled cyclist lost control going southward and fell into the river.

We averaged 5mph. On regular roads, I would have done the trip in less than half the time (in part because the road goes pretty much straight there, while the ‘so-called’ multi-use trail takes a dog-leg approach alongside the river). Also, this trail is overgrown with weeds, is ‘paved’ with loose pebbles the size of golf balls, and is 4 ft wide in places with mud patches and 10+ft drops on each side. In my view it is the worst bike trail I’ve ever seen and is literally a death trap for cyclists (which is presumably why bike trail advocates avoid referring to it as a bike trail). Sadly, most so-called bike infrastructure is poorly designed, poorly implemented and lacking in funding for maintenance. I have yet to see a bike trail or bike path that is well designed, well implemented and well maintained. Until I do see such a thing, I am 100% against such follies.

The photo below was taken around 12 noon on June 3 somewhere near White’s Ferry and is the only image I have showing the actual trail. It shows what should be considered a ‘good’ part of the trail in this area – this part is wide, relatively flat and has only a gentle slope away to the canal on one side. As you can see, even though there’s perhaps 8ft of trail, most of it is grassed over and there’s only two thin tracks of usable surface. Sometimes the trail gets so treacherous that the wet and slippery grass in the middle becomes the safest place to ride.

A better section of the C&O towpath trail

A better section of the C&O towpath trail

The C&O has few road crossings, it’s true. But if you use it in May or June, before the flood season is completely over (and presumably before any yearly maintenance is carried out before the summer season), you see it at its worst, when it is difficult just to maintain control of the bike. At some points, especially the stretch between Seneca and Point of Rocks, MD, it is quite literally frightening. In many places the trail is very narrow, it has a steep ten foot drop on one side to the old canal, and a steep twenty foot or more drop on the other side to the river (sometimes both at the same time). In May and June, the trail is so overgrown that stinging nettle bushes often thrust out into the trail. The trail is filled with pebbles and rocks, and overgrown grass and stinging nettles sometimes make all but a section between 6 and 12 inches wide unusable. This thin section can be muddy, it can change from dry to wet very quickly, it can be deeply rutted from use by previous cyclists, and other parts can be washed out so badly that cyclists can experience sudden potholes. It is extremely treacherous.

In my view, this stretch of the C&O Canal towpath should be closed as a multi-use path as its lack of adequate maintenance means that it is only a matter of time before a cyclist or a runner gets killed on it.

Save

Why this crash?

The fancy, expensive bicycles and racing clothing are not matched by these cyclists’ bike handling skills.

If you play the video through to the end, you will see that the wheel touch broke 4 of the 8 spokes on the right side of the boutique 16-spoke front wheel.

Detailed explanation:

  1. Boutique wheel, few spokes, spokes necessarily overtensioned, big gaps for things to get in between them.
  2. Rider ahead merged left and slowed (notice backpedaling), oblivious to riding in tight group.
  3. Tri bars and no brake there.
  4. Overlapping.
  5. Spokes broke against QR handle. At this point overlap was by more than half a wheel.
  6. Still a good recovery.
  7. Inability to steer due to unstable front wheel and to need to move hands position to brakes — cyclist heads for ditch.
  8. Attempt to brake on warped front wheel locked the wheel.

Some commenters on the YouTube post have pointed out that the cyclist who crashed was wearing a sleeveless jersey and not wearing socks. This clothing is characteristic of triathletes — who don’t ride in groups while racing and are less likely to learn group riding skills than are road racers. Another point about clothing is that the cyclist wasn’t wearing cycling gloves. He broke his fall with his hands on gravel. Ouch.