Traffic accident statistics indicate that human error contributes to the majority of road accidents. Certain types of accidents predominate. In particular, vehicles turning right to cross oncoming traffic at marked and unmarked intersections account for approximately one quarter of all accidents. It is this type of accident to which motorcyclists are particularly vulnerable.
Accident analysis has become increasingly sophisticated in the past two decades. Research has moved beyond working out what happened and increasingly analyses why an accident happened. It is this information that is useful for us motorcyclists.
Researchers in the USA and Japan equipped hundreds of cars with video and sensor recorders to record traffic conditions and driver behaviour, including driver gaze (where the driver was looking), GPS location data, vehicle speed, accelerator pedal position, steering angle, and turn signal activation. This is what they found.
A significant number of accidents, whether with oncoming vehicles or pedestrians, involved vehicles making right turns at intersections in a particular way. What is remarkable is that the researchers were able to re-create the accident scenarios on a close circuit and watch test subjects make the same mistakes. Certain driving situations produce much higher accident rates than others.
From the perspective of the motorcyclist this is interesting because it draws our attention to one of the highest risk road situations. If we can identify the problem, perhaps we can do something to avoid it.
If you look through the photographs below you can see how the typical “right hand turn” accident develops.
Notice the position of the motorcyclist in the photo “3 seconds to near miss.” He is either obscured or partially obscured from view to right turning traffic by a vehicle in front (“oncoming vehicle 3”).
As the “oncoming vehicle 3” makes the turn, the motorcyclist carries on into the path of the “Test vehicle.” This is the point at which the accident occurs.
Let’s view the accident situation from the point of view of the car driver.
One can see from the video stills above that it is only if the car driver’s gaze point is close to that of the motorcycle when he emerges from behind the oncoming car that the turning car driver might stop in time. The research found that if the car driver had already begun the turn (in other words their foot was on the accelerator and not the brake) they would take more than twice as long to stop. The average reaction time in this case was 1.7s. How far will the bike have travelled across the junction in 1.7s? It would be safe to assume the worse.
That the researchers were able to reproduce the accident reliably indicates the right hand turn can be a remarkably efficient, and lethal, trap for both car and motorcycle drivers.
As a motorcyclist, to avoid this type of accident it is essential one recognizes and anticipates the danger and adjusts one’s speed so the motorcycle can be brought to a halt safely. Do NOT trust that drivers making a turn have either seen you or that they have correctly estimated your speed.
A separate research study in Malaysia concluded that an increase in approach speed of the motorcycle is associated with an increase in motorcycle crashes. It is self-evident that approach speed is important in the right hand turn crash.
So, how to avoid right hand vehicle turns that kill motorcyclists?
(1) Anticipate that a vehicle that can not be seen might appear from an obstructed view-point on an intersection.
(2) Position one’s motorcycle to maximize visibility both of the intersection and so that the motorcycle is conspicuous to other vehicles.
(3) Don’t lane-split down the side of a vehicle that is making a right hand turn ahead. There is no visibility through the vehicle, and another vehicle turning across your path would not be visible. Don’t risk it.
(4) Reduce your speed so that in the worst-case scenario the motorcycle can be brought to a halt before hitting a right turning vehicle.
While not a research conclusion, one might consider circumspection when faced with the typical U-turn where it is commonplace for drivers to creep forward to complete their manoeuvre while waiting for traffic to pass. It is not unreasonable to reduce one’s speed to negotiate the area where the driver will turn (while remaining aware of the risk of being rear-ended by following traffic). One of the key research findings was that it is very difficult to estimate the speed of an oncoming motorcyclist and poor estimation by drivers initiating a turn frequently causes an accident.
A modified version of this article appears on the GT Rider forum.
1. Nobuyuki Uchida, Maki Kawakoshi, Takashi Tagawa, Tsutomu Mochida, An investigation of factors contributing to major crash types in Japan based on naturalistic driving data, 2010, IATSS Research
2. V.L. Neale, T.A. Dingus, S.G. Klauer, J. Sudweeks, M. Goodman, An Overview of the 100-Car Naturalistic Study and Findings, 2005 ESV Paper Number 05-0400.
3. S.Harnen, R.S.Radin Umar, S.V.Wong, W.I.Wan Hashim, Motorcycle Crash Prediction Model for Non-Signalized Intersections, 2003, IATSS Research Vol 27, No 2.