NMAA has recently been cited as calling for higher highway speeds in Fairfax media and
numerous radio stations mainly in Australia. We believe that a sensible
debate is needed regarding higher speed limits on certain roads to
improve safety by reducing fatigue and other factors.
Ironically
the thing that sparked this issue is the recent call by the RTA to
reduce the speed limit on the Newell Highway from 110 to 100 km/h which
made even the very conservative NRMA uncomfortable.
The RTA apparently have a report that recommends such a move based
on the belief that it would likely reduce the road toll, however there
has been virtually no consultation. Furthermore there is research that
suggests lower speeds on good roads may increase fatigue and even
increase the road toll.
This is a very complex debate that for
too long has been dominated by the assumption that "slower is safer".
which fits neatly with the "speed kills" and "feel guilty if you get a
speeding ticket".
Some of the other factors that we believe are relevant include:
- There are many Australian highways that are built to an extremely
high standard yet the maximum speed is only 110km/h (e.g. the M1
between Brisbane and Gold Coast is 8 lanes and could easily sustain
130km/h safely)
- The Australian highway network built in the 1970s had a design speed of 130kph.
- Automotive technology has advanced dramatically over the past 50 years yet the highway speed limits have barely changed
- Since the NT repealed the unlimited highway speed limit and
introduced a 130km/h limit in 2007 the NT road toll has increased
substantially
- In America the Minnesota Department of Transportation compared
July-Sept 1996 with July-September 1997. Driving speed went up from
61mph to 66mph on the Interstate freeways. During the period there was
a 20% reduction in deaths.
- Italy has recently (July 2009) increased the highway speed limit to 150km/h.
- Whilst in the act of overtaking (on the opposite side of the road)
it should be legal to briefly exceed the posted speed limit so as to
complete the manoeuvre more quickly and thus reduce the exposure to
danger of head-on collision. Legally briefly exceeding the speed limit
in that situation can also reduce the frustration leading to poor
driving for drivers who are stuck behind a slow vehicle for a long
period without the opportunity to legally overtake.
- A slight increase in speed over a long journey can significantly
reduce journey times. This and the reduced boredom is likely to reduce
the possibility of falling asleep at the wheel. Indeed NRMA president
Wendy Machin pointed out that a 10km/h change in speed limit (a
magnitude of change little more than walking speed) on the Newell
Highway (which connects Victoria and Queensland through NSW) would add
an hour of journey time travelling between Queensland and NSW. So a
driver going only 10km/h faster could be in bed while another driver
had an hour to go on the road. The implications for driving fatigue are
obvious.
- Canadian brain researchers Hal Weinberg PhD and Michael Gaetz from
the Brain Behaviour Laboratory at Simon Fraser University suggest that
the ability of the brain to react to unexpected events depends on an
optimal range of speed rather than simply going slower. They write "If
events are changing very slowly but something happens suddenly,
requiring an immediate response, the brain may react less efficiently
than if events had already been changing more rapidly. Similarly,
drivers may be able to discriminate and handle distractions better --
another critical form of processing additional information -- when
their minds are already fully engaged, rather than having to shift
suddenly from more automatic behaviour. But again only up to a point."
Are you driving too slow for the unexpected?
- We believe that driver training should be emphasised and this will
never occur when governments can be seen to be doing something based on
the speed kills mantra. Without public pressure there is little
motivation to action this as vastly improved driver training costs
money and enforcing 1940s speed limits makes money.
- With better roads and better driver training we can drive faster and safer.
- Official scare tactics to gag this debate tend to be loose with
facts to promulgate a slower is always safer perception. For example
back in 2002 NMAA secretary Jim Wright pointed out that Queensland
braking distance ads "fudge both reaction time AND stopping distances.
Many use half the typical braking rate and three times the typical
reaction time.” He observed that halving the deceleration and tripling
the typical reaction time to mislead the public and justify its cash
grab is inexcusable .” The ads assume a reaction time of 1.5s. However
study of the average reaction time for stepping on a brake pedal in
response to a light for 20 year olds was .44s increasing to .52s for 70
year olds (Olsen P L. Driver Perception Response Times.; Accident
Reconstruction Journal 1991 Jan/Feb; 3 (1): 16 – 21, 29.) The stopping
distances are calculated based on a deceleration of 4.5m/s/s. That rate
of deceleration is just under half the deceleration of a typical car in
a road test.
- Contrary to braking distance ad innuendo raw speed and crash risk
are not directly related (no linear relationship) as most drivers don't
have a death wish and just want to drive at a reasonable speed. Like
steering the car, choosing a speed is a basic skill. There is a
U-shaped relationship between speed and crash risk. Nuclear physicist
Alex Kuznetsov engaged in a mathematical analysis of speed and crash
risk. His model indicated that deviation from flow of traffic upward or
downward is the primary determinant of crash risk. American researcher
Solomon way back in the 1950s demonstrated this relationship using
crash records of highway traffic. His findings of a U-shaped
relationship have been replicated many times.
- Jurisdictions with a high percentage of speed related crashes
typically use a bizarrely broad definition of speed related which makes
no sense to most people. Prior to the introduction of speed cameras
official statistics of the Queensland traffic authorities indicated
that speed was a factor in only 4% of crashes (the Adelaide In Depth
Study finding was virtually identical). As the percentage curiously
went up after speed cameras were introduced we can't help suspect that
a disingenous broadening of definition is used to support revenue
raising by hiding the reality that speed is a very low contributer to
accidents.
- By comparison NRMA president Wendy Machin pointed out that fatigue
related crashes account for 26 percent of crashes on the Newell Highway.
- Reasonable speed limits can free up enforcement resources to target truly dangerous drivers.
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National Motorists Association Australia 
