Trucker's view of calming in the U.K.
·
By: Gordon Pye
· Date:
1996-09-09
To use fuel efficiently, the driver of a heavy vehicle needs to store
the energy contained in the vehicle. Traffic calming is perhaps the
greatest waste of fuel ever devised. One new roundabout, causing an
average speed reduction of 30 Kph, traversed five times loaded at 32.5
tonnes, and four times at 11.5 tonnes, used on average 2 gallons extra
fuel per day. This can be proved by mathematical calculation, but I have
never seen the equations in any text book. I have undertaken a rough
calculation of the extra fuel used by causing a heavy vehicle to stop or
slow. The roundabout calculation shows that fuel consumption is doubled
over a certain road section from the start of braking, to the end of
acceleration. This will be true for all vehicles forced to stop or slow.
The same principle applies to all vehicles if the stored energy has to be
wasted through the brakes.
I have recently heard that all new or improved major roads in
Lancashire must have roundabouts at all junctions with less than 1 km
vision in both directions. The roundabout recently constructed on the A59
near Clitheroe is so tight for Heavy Goods Vehicles (HGVs), that it will
reduce speed to under 20 Kph for vehicles traveling up grade. It is also
guaranteed to increase congestion, therefore using extra fuel. Even though
the road is dual carriageway, the roundabout has only one true lane
through it, unless everyone drives a Nissan Micra. If anyone had
deliberately set out to design a death trap for cyclists, it is doubtful
whether they could have made a better job of it. Drivers at a nearby
cement works are experiencing vehicle stability problems at low speed in
the eastbound (empty) direction. Their union representatives have asked
the company to contact the local highway authority in an attempt to get
the roundabout modified into a safer layout.
Miles per Gallon is not a true measure of fuel consumption. The true
measure is grams per kilowatt hour, as used by transport engine
manufacturers. The total amount of time under power is the factor which
determines Mpg. Almost all internal combustion engines are most efficient
at or near full load. This is because the heat lost through cooling and
the exhaust is almost constant under any load condition.
Developments such as power steering, air conditioning and even electric
windows all consume extra fuel. Air conditioning is perhaps the most
environmentally damaging development, as it consumes a vast amount of
extra fuel. Average family cars fitted with power steering may use up 10%
more fuel than non fitted vehicles. The addition of air conditioning may
increase fuel consumption by a further 15% or more?
Factors such as these can make recent theoretical improvements in
thermodynamic and emission performance quite meaningless. Almost all new
cars come with power steering and or air conditioning as standard. If the
public were aware of the extra pollution caused by these extras, perhaps
the manufacturers would be forced to abandon them as standard.
Road safety is usually the reason used to justify traffic calming
schemes, but most are designed to slow the average family car. To the HGV
driver, most new junction layouts cause more potential safety problems
than the ones they replaced. Road design appears to have more to do with
the need to accommodate standard kerb (curb) components, than the physical
needs of long vehicles. Modern road design takes no account of the turning
space that a long or articulated vehicle needs. The junctions and
roundabouts are quite adequate for the needs of a car, but the lanes are
usually impossible for HGV's or buses to follow. Apart from causing
additional safety problems for other road users, bad road design also
increases wear and tear, driver fatigue, and thus the ultimate safety of
the vehicles themselves. I have been reliably informed that new traffic
calming under rail bridges is largely responsible for the recent high
number of bridges hit by high vehicles? The present situation is probably
the result of a whole generation of road designers being taught the
perverse theory that, "making roads more dangerous makes them safer."
Inappropriate traffic calming on routes frequently used by HGV's and
buses causes additional problems. Once wide roads which once caused few
problems are now filled with pinch points and traffic islands. Most new
roads are a series of traps to catch cyclists and incompetent car drivers.
The specified minimum safe distance from the kerb was 18 inches when I
passed my HGV test in 1982 . This distance is impossible to achieve where
traffic calming measures exist. Traveling close to the kerb is bad for
pedestrians, especially when pools of water form in holes or hollows. The
A59 at Copster Green between Preston and Clitheroe carries a large amount
of extra HGV traffic from the cement works, and roadstone quarries at
Clitheroe, and the quarries in the Craven area of North Yorkshire. The
road was improved during the 1960s and did not require resurfacing until
about 1990. Two years ago, Lancashire County Council introduced traffic
calming measures at Copster Green. In addition to a 40 Mph speed limit,
several traffic islands were built into the centre of the wide road. Since
the introduction of central traffic islands, all HGVs are forced to travel
close to the nearside kerb. This has caused excessive damage to the
nearside of the road in both directions. Almost all the drain grates have
been pounded well below the road surface and the surface is cracking up
next to the kerbs. This creates additional dangers for cyclists.
In just a couple of years, the traffic islands at Copster Green have
caused the same amount of damage which one would expect after about 15
years or more for a similar wide road. The extra maintenance of the
carriageway must place extra demands on natural resources. Patching roads
usually means that more material than needed is ordered. The spare
(usually at least a ton) ends up being tipped back at the quarry, unless
the driver can find someone who has a use for it, then only if its the
last load of the day.
Traffic Calming encourages lunatic drivers to attempt an overtaking
maneuver on the approach to pinch points, or roundabouts . It is
impossible for vehicles to follow a true safe line through any of the
obstacles after the road alleged safety improvements. Road design is a
major factor in overall road safety, but is seems as though no one is
prepared to take this important factor seriously. Many accidents involving
goods vehicles are a direct result of poor road design. Adverse cambers
and other ideas designed to slow traffic are built in to almost all new
roads.
Road design appears to be immune from scrutiny by accident
investigators, even though it is the probable cause of many accidents.
Most new road junctions are designed to cut the speed of vehicles using
them. However, designing roads with impossibly low safe speeds is counter
productive in the case of heavy goods vehicles. Being crushed by a goods
vehicle ( or its load ) traveling at 5 Mph leaves you just as dead as one
traveling at 50 Mph. Modern road layouts almost all incorporate features
which can set up a pendulum effect in high vehicles and lead to slow speed
roll-over. The driver can counteract this effect by use of the accelerator
to provide a force to cancel out the effect. Being forced to apply the
brakes, or cut the accelerator at the wrong moment during the pendulum
cycle is extremely dangerous.
Continual braking and accelerating also causes the brakes of HGVs to
rapidly overheat and "fade" thus significantly increasing the stopping
distance in an emergency. This factor is compounded on vehicles fitted
with ABS, but that's another story.
Air pollution could also be reduced by reversing the present theory of
traffic management by traffic calming. In many cases this would cost very
little as it mainly involves altering the phasing of traffic lights. The
replacement of all small diameter roundabouts on major roads would also
produce a useful reduction in emissions from all vehicles. Part time
traffic signals and "free give way" left turns could replace many current
roundabouts and other permanently controlled junctions, without a
significant reduction in safety.
The recent development of speed cameras offers a unique opportunity to
depart from the use of potentially dangerous road layouts to control the
speed of vehicles. Roads could once again be laid out to suit the true
safe turning characteristics of vehicles, as demonstrated when snow
obscures the lane markings. By getting rid of the need for small
roundabouts and any other forms of traffic calming, land, fuel, tyre wear,
and other vehicle maintenance is saved; road maintenance will also be less
frequent and easier. Thus we would likely see cost savings for everyone
and benefit to the environment all round. |