- The chances of a fatal collision with a pedestrian are linked to the speed of impact: At 20km/h 4% of collisions are fatal. This rises to 9% at 30km/h, 25% at 40km/h 83% at 50km/h and, in effect, 100 % at 60km/h. Impact speeds can also be related to equivalent drop height, onto a hard surface: 20km/h=1.6m drop height, 40km/h = 6.3m drop height, 60km/h = 14.2m drop height (that is, a drop from a 4th floor balcony) and 80km/h = 25.2m drop height.
- Vehicle frontal design has a slight influence but there is no better countermeasure than reducing (or eliminating) the speed of impact.
- In about half of all pedestrian accidents the motorist has virtually no chance of braking or swerving - the speed of impact is close to the initial speed of the vehicle (see also the 1996 ESV paper by McFadden). In many cases there is just no warning and the motorist would need X-ray vision to be able to brake before an impact! In-depth investigations into 103 child pedestrian accidents in Chicago indicated that at least 72% involved "sudden appearance" of the pedestrian where the driver was unable to take avoidance action (Schofer et al, Accident Analysis and Prev, 1994)
- One problem is that driver's gain a false sense of security because
- VEHICLE SPEEDS SHOULD BE NO MORE THAN 40km/h WHERE THERE IS A HIGH RISK OF A COLLISION WITH A PEDESTRIAN! Particularly at school home times any motorist on the road should expect to have to slow to no more 40km/h when child pedestrians are about, such as outside schools or when passing bus stops.
- NRMAs comments about lower residential speed limits.
Road Safety Tips
Over the last few years I have conducted investigations on several road safety related subjects. There are a couple of points about driving which stand out from this research. They are raised here because they tend to have been over-looked by road safety authorities in road safety campaigns.A. VEHICLE SPEEDS AND PEDESTRIANS
See also Devices to help drivers control their speed.Updated 3 November 97, based on the paper "Vehicle Travel Speeds and the Incidence of Fatal Pedestrian Crashes" by Anderson, McLean, Farmer, Lee and Brooks, J. Acc Anal. and Prev, Sept 1997.
(1) encountering a potential pedestrian collision is (fortunately) an extremely rare event and
(2) the road environment (and caution shown by road users) has generally evolved to cater for typical traffic speeds. These typical traffic speeds are simply too high when the road environment changes (for example, narrow streets with parked cars) or when inexperienced vulnerable road users are about.
B. PARTIALLY RUNNING OFF THE ROAD AND OVER-CORRECTING
During a study of rollover crashes in Australia I analysed dozens of fatal accident reports. A recurring description in these reports was "ran off road then over-corrected". In Australia many rural roads have unsealed edges and there is usually a slight step up from the unsealed edge to the sealed road surface. What appears to be happening frequently is that a motorist (particularly an inexperienced driver) accidentally lets the nearside wheels deviate onto the unsealed edge of the road. They then panic and quickly turn the steering wheel to return onto the sealed section. The problem is that, as soon as the nearside front wheel returns to the tar, the lateral (sideways) forces acting on the vehicle almost double and the vehicle suddenly veers onto the wrong side of the road (see animation). A head-on collision or roll-over is a strong possibility. A vehicle will travel quite safely, and will brake at a moderate level in a controlled manner even if one side is on dirt and the other is on tar - the wheels on the tar will keep you travelling in a straight line. You don't need ABS brakes to slow down in these circumstances, provided you don't brake so hard that the wheels on the tar lock up.IF YOU RUN OFF THE SIDE OF THE ROAD DON'T PANIC - GENTLY SLOW
THE VEHICLE
DOWN AND RETURN TO THE TAR WHEN THE SPEED IS LOWER.
C. ADJUSTABLE HEAD RESTRAINTS
As a guide, the top of the head restraint should be no lower than eye level. This is slightly higher than the typical height of the centre of gravity of the head and so the head restraint should "catch" the head without causing severe rotation in the event of a rear-end collision. Never leave the head restraint pushed fully down. See the Insurance Institute for Highway Safety site for a comprehensive report on head restraints (Status Report).D. CHILD RESTRAINTS IN AUSTRALIA
Note that, for more than two decades, Australia has required
child restraints to have top tethers. In-depth accident studies show
that child restraints with top tethers perform exceptionally well in
severe crashes. Always attached the top tether to the appropriate anchorage in the vehicle and tighten the tether.
Important updates
2021: NeuRA and Kidsafe Australia release updated National Child Restraint Guidelines + National Child Restraint Best Practice Guidelines + Downloads here [comment: while the Guidelines make frequent reference to shoulder heights markers the brochure does not refer to them - these are an important guide to determining whether the child is too small or too large for the child restraint]
2019: Since 2013 Australian child restraints have been required to have shoulder height markers to easily identify whether a child is too small or too large for a particular child restraint. See A Safe Ride Height Line for Child Car Occupants (2009 ESV paper)
2015: ChildCarSeat.com.au - Child Restraint Evaluation Program and other safety tips.
24 Feb 14 NEURA: National Child Restraint Best Practice Guidelines - latest expert advice and the brochure:
Keeping children as safe as possible when travelling in cars. Updated in 2021.